Country Pasture/Forage Resource Profiles
New Zealand - part 2
3. CLIMATE AND AGRO-ECOLOGICAL ZONES

Climate
New Zealand is located in the temperate climatic zone and exhibits a strong oceanic influence which results in rapidly changing and variable weather patterns. Weather is most changeable in spring (Sept-Nov) and early summer and more settled in late summer and autumn (MetService, 2008; NIWA, 2009).

Anticyclones approach from the west across the Tasman Sea and bring settled weather conditions to most of the country. Low pressure troughs (depressions) of varying strength are interspersed between the anticyclones and move up the country from the south. In winter months, these depressions can bring rain, sleet and snow. The majority of snow falls on the Southern Alps of the South Island and Central Plateau of the North Island but may occasionally fall to sea level in Southland, Otago and Canterbury.

The mountainous terrain has a strong influence on regional climates. There is a strong rainfall gradient from west to east, particularly in the South Island (Figure 7). This results from the rain shadow formed by the Southern Alps. Long-term mean annual (1951-1980) rainfall ranges from 360 mm (Alexandra, SE South Island, 45.267°S, 169.383°E) to >6 700 mm at Milford Sound (SW South Island, 44.667°S, 167.917°E). The maximum recorded annual rainfall was 18 000 mm on the West Coast of the South Island (Crop River, Hokitika catchment). Annual rainfall is between 600–1 500 mm for most of the country but large areas of both islands receive >2 500 mm/yr. In most locations, long-term mean monthly rainfall may show slight seasonal variation which is insufficient to replenish the soil water used when potential evapotranspiration increases in summer months. This leads to the development of summer soil moisture deficits that restrict pasture growth. On the east coast of both the North and South Islands these deficits can develop between September and April before autumn rainfall alleviates water stress conditions. 

The gradient in mean annual temperature runs north to south. Mean annual temperatures are 16-18°C in the northern North Island and 8-10°C in the south of the South Island. Mean annual temperatures also decrease by about 2°C for every 300 m increase in altitude. Mean annual sunshine hours (1971-2000) are between 900 and 2600 hours/yr. The lowest sunshine hours (900 to 1 400 hr/yr) occur in Fiordland and parts of the west coast of the South Island. The highest (2 200 to 2 600 hr/yr) occur in the northwest of the North Island and the top of the South Island.

Figure 7. Long-term mean
annual rainfall (right) and air temperature (left) in New Zealand (NIWA, 2009).

[Click to view full images]

Temperature
There is a strong seasonal variation in mean air temperature (Figure 8) which is typical of a temperate climate, but it is moderated by oceanic influence. Temperatures are highest in the summer months (Dec-Feb) and lowest in July. In eastern areas, maximum daily temperatures may be >30°C in mid summer (1-10 days/yr). Nationally, the maximum recorded daily temperature was 42°C in eastern regions of the South Island. The annual temperature range is 8-10°C except for inland South Island (>11°C) districts where there is a maximum difference of 14°C in Central Otago which has a continental climate. At Ophir (Central Otago) the national maximum recorded temperature range was 55°C being the lowest recorded of -22°C in winter and up to 33°C in summer.

Figure 8. Monthly variation in long-term mean air temperature (oC) at selected New Zealand locations as listed. North Island sites: Kaitaia (35.135°S, 173.262°E, 35 m), Taupo (38.683°S, 176.067°E, 376 m), Napier (39.500°S, 176.917°E, 2 m). South Island Sites: Christchurch (43.533°S, 172.617°E, 7 m), Mt Cook village (43.733°S, 170.100°E, 762 m), Alexandra (45.267°S, 169.383°E, 141 m) and Milford Sound (44.667°S, 167.917°E, 3 m) (NIWA, 2009).
[Click to view full image]

This seasonal temperature variation affects the length of the growing season and consequently the potential production that can be achieved in specific regions. Table 4 shows the amount of thermal time accumulated above a base temperature of 0°C from long-term data at selected locations from 1 July to 30 June.  Of these, the longest growing season occurs in Kaitaia (5 730°Cd) and the shortest growing season is at Invercargill which is 40% lower (3 563°Cd) but the growth season here is severely restricted by killing frosts.

Table 4. Accumulated thermal time (above a base temperature of 0°C) at selected locations throughout New Zealand. Data are means from sites having at least five complete years of data.

Location

Accumulated thermal time (°Cd)

Kaitaia

5 730

Gisborne

5 194

Napier

5 269

Wanganui

5 105

Blenheim

4 666

Westport

4 581

Christchurch

4 370

Invercargill

3 563

Rainfall
Geographically, the highest rainfall typically occurs on the west coast of both islands where the mountains are exposed to westerly and north-westerly winds from depressions approaching from the southwest. For a large part of the country, long-term records indicate rainfall is distributed reasonably evenly throughout the year (Figure 9). The greatest contrast is found in the north, where winter rainfall is almost double that which occurs in the summer months. The predominance of winter rainfall diminishes as you travel south but it is still discernible over the northern part of the South Island. In the southern half of the South Island, rainfall is lowest in winter months and a summer maximum occurs inland due to convectional showers. Rainfall is most reliable in spring and least reliable in summer and autumn.

Figure 9. Long-term mean monthly rainfall (mm) at selected New Zealand locations as listed. North Island sites: Kaitaia (35.135°S, 173.262°E, 35 m), Taupo (38.683°S, 176.067°E, 376 m) , Napier (39.500°S, 176.917°E, 2 m). South Island Sites: Christchurch (43.533°S, 172.617°E, 7 m), Mt Cook village (43.733°S, 170.100°E, 762 m), Alexandra (45.267°S, 169.383°E, 141 m) and Milford Sound (44.667°S, 167.917°E, 3 m) (NIWA, 2009).
[Click to view full picture]

Rainfall is also influenced by seasonal variations in the strength of the westerly winds. Spring rainfall is increased west of, and in, the mountain ranges as the westerlies rise to their maximum strength in October. Consequently, there is an unavoidable but complementary decrease of rainfall in the lee of the ranges. Long-term records mask this annual variation. For example, at Lincoln, Canterbury, the long-term (1975-2007) mean annual rainfall is 627 mm/yr but has ranged from a minimum of 308 mm (1988) to a maximum of 1 015 mm in 1978. Average monthly rainfall indicates a reasonably even distribution of ~50 mm/month throughout the year with slightly more rainfall in winter months. However, Figure 10 shows that in July (winter), which has a long-term mean monthly rainfall of 63 mm, the minimum rainfall was 11 mm (2000) and the maximum was 161 mm (1977). In December (summer), with a long-term mean monthly rainfall of 54 mm, the minimum was 1 mm (2003) and the maximum was 157 (1978). Thus, rain tends to fall in large (30-130 mm) events at infrequent intervals throughout any given year.

Figure 10. Total monthly rainfall (mm) in July and December from the Broadfields Meteorological Station located 2 km north of Lincoln University, Canterbury, New Zealand between 1975 and 2007. Long-term monthly rainfall, calculated for the 1975-2007 period, indicate a mean monthly rainfall of 63 mm in July (winter) and 54 mm in December (summer).

Potential evapotranspiration and potential soil moisture deficits
Daily potential evapotranspiration (PET) throughout New Zealand varies between a minimum of 0 mm/d and a maximum of about 12 mm/d. As expected, long-term mean daily PET is highest in summer and lowest in winter. For example, Figure 11 shows long-term monthly PET in winter at Gisborne increases from 1 mm/d in July to 5.2 mm/d in Dec/Jan. In Alexandra, mean daily PET is 0.1-0.7 mm/d between May and August and then increases to >4 mm/d in summer months.

A potential soil moisture deficit (PSMD) can be calculated as the difference between PET and rainfall in a July-June growing season. When potential soil moisture deficits exceed 100 mm pasture production is compromised and significant losses occur when deficits exceed 150 mm (McAneney et al., 1982). In eastern New Zealand potential soil moisture deficits accumulated across the entire growing season commonly reach 300-500 mm/yr. It reaches 100 mm by the beginning of summer and a further 120-150 mm accumulates by the end of summer (Salinger, 2003). In Napier the long-term (1930-2002) mean potential soil moisture deficit is ~450 mm/yr and ranges from 170 to 660 mm/yr (Figure 12). In Ashburton the long-term PSMD is ~325 mm/y and ranges from 120 to 540 mm/yr. Table 5 shows that PSMD exceeded 100 mm by the 1st of December in 85% of years in Napier and in 51% of years at Ashburton. Severe water stress (PSMD >150 mm) occurred by 1st December in 55% of years at Napier compared with 18% of years at Ashburton.

Figure 11. Mean daily potential evapotranspiration (PET) at Gisborne and Alexandra. Gisborne data is for the period 1975-1992 (38.661°S, 177.986°E, 4 m) and Alexandra data is for the period 1975-1983 (45.258°S, 169.389°E, 141 m).

Figure 13a shows the extent of the potential soil moisture deficit, based on potential evapotranspiration (PET) for dryland areas (no irrigation) on the 31 December (mid summer) across New Zealand. The historical average is shown for comparison with the situation in December 2007 (drier than average) and 2008 (drier than average particularly on the west coast of both islands). Note the effect of the rain shadow, from west to east, cast by the Southern Alps in the South Island and to a lesser extent the mountains in the North Island. Figure 13b shows the regional variation in the longterm median number of deficit days which occur annually. This ranges from 0-5 days/yr on the west coast and at higher altitude mountainous sites to > 120 days in areas on inland Otago and coastal areas on the east coast of both the North and South Islands. The soil water storage for plant growth is also affected by soil type (texture, proportion of stones, soil depth to stones or rock), plant water extraction ability (rooting depth, timing of peak seasonal demand) and local variations in rainfall. The variation in soil depth and associated presence of intergrade soils means differences occur over small (< 10 m) distances. These factors are not accounted for in potential soil moisture deficit calculations which are based on potential evapotranspiration, and represent the difference between rainfall receipts and atmospherically driven demand.
Figure 12. Potential soil moisture deficit (mm/y) accumulated over Jul-Jun growing seasons for Napier (top) and Ashburton (bottom) between 1930/31 and 2001/02 (Salinger, 2003).

Table 5. Magnitude of potential soil moisture deficit (PSMD, mm) at Napier and Ashburton from 1930/31 to 2001/02 (Salinger, 2003).

 

Napier

Ashburton

PSMD

No. years

% years

No. years

% years

1 Jul-1 Dec >100

60

85

36

51

1 Jul-1 Dec >150

39

55

13

18

1 Jan-1 Mar >100

61

85

49

69

1 Jan-1 Mar >150

37

52

23

33


Figure 13a. Potential soil moisture deficit, calculated from potential evapotranspiration assuming no irrigation is applied, on 31 December showing the historical average (left), December 2007 (centre) which was a drier than average year and in 2008 (right) which was slightly drier than average particularly on the wetter west coast. The water balance used in the calculation for deficit development within the root zone was based on an “average soil type” with a plant available soil water holding capacity of 150 mm (NIWA, 2009).
[Click to view full image]
Figure 13b. Long term (1971-2002) annual median number of deficit days occurring in different regions of New Zealand. Deficit days are defined as the number of days where the potential soil moisture deficit exceeds 75 mm with potential soil moisture deficits using an “average soil type” with a plant available soil water holding capacity of 150 mm (NIWA, 2009).
[Click to view full image]

 

Winds
The mountain ranges also modify wind patterns but annually mean wind speed ranges between 10 and 18 km/h. The moist westerly anticyclones which result in the high rainfall on the west coast push drier westerly windflows up over the dividing ranges. This results in the development of low humidity (5-30%), warm ‘főhn’ winds which move rapidly across the eastern areas of both islands. As the wind speed increases topsoils of recently cultivated or summer dry paddocks may be blown away and in extreme cases, wind throw of plantation trees and damage to buildings may occur. New Zealand’s location in the southern ocean results in high total wind run in many locations. Figure 14 shows mean daily wind run at four locations in New Zealand tends to be highest in spring and lowest in winter months. For Wanganui the maximum daily wind gust was 111 km/h in Feb 2004 and in Wellington the maximum recorded gust was 161 km/h in Aug 1975. Tornadoes occur rarely but can remove roofs and cause trees and power lines to fall. These events tend to occur when moist anticyclones move across New Zealand in a northerly direction from the subtropics but this is not the dominant weather pattern.

Figure 14. Long-term mean monthly wind run (km/d) at Wanganui (39.9388°S, 175.045°E, 15 m, 1996-2009), Wellington (41.286°S, 174.767°E, 125 m, 1975-1998), Blenheim (41.5231°S, 173.865°E, 35 m, 1990-2009) and Lincoln (43.62622°S, 172.4704°E, 18 m, 1975-2007).

Frost and snow events
Annually, the average number of ground frosts increases from 1 d/yr in Kaitaia (northern North Island) to >90 d/yr in Invercargill (southern South Island) (Table 6). Frosts are generally rare between mid October and April but may occur at any time in some southern and elevated parts of the country. Unseasonal spring frosts can have a large economic cost particularly to the viticulture and horticultural industries. When frost warnings are put in place a range of methods which include helicopters and wind turbines are used to create air movement and prevent damage to fruit. Snow may fall to sea level for short periods of time on the east coast of the South Island and in inland Canterbury and Otago. Serious stock losses may occur in winter if farmers fail to move stock to more sheltered areas especially where grazing occurs at >330 m.

Table 6. Number of ground frosts annually at selected locations throughout New Zealand. Data are means from sites having at least five complete years of data.

Site

No. ground frosts

Kaitaia

1

Gisborne

33

Napier

29

Wanganui

7

Blenheim

60

Westport

26

Christchurch

70

Invercargill

94

Agro-ecological zones
Table 7 quantifies land use based on farming enterprise and dominant land cover classes through New Zealand and the total land area they cover as determined in 2004 (Ministry for the Environment, 2007). Pastoral based production accounts for 37% of the total land mass. Exotic forestry, predominantly from Pinus radiata, accounted for 7.3% of land area use. Agriculturally non productive native forest, tussock grasslands, scrubland, waterways and snow and ice accounted for >50% of land cover.

O’Connor (1993) summarised the main activities and identified 14 distinct landscape areas for New Zealand each of which differ in their dominant land use. More than one activity can occur within any agro-ecological zone. For example, arable production is mostly on flat to rolling land. Consequently, the majority of cereal and herbage seed production occurs in mixed cropping farm systems on the alluvial floodplains of the South Island. Most of the kiwifruit and citrus production occurs in the north of the North Island where higher rainfall and warmer temperatures are suitable for warm climate fruit production. Pastoral production occurs in parts of all landscape regions but the main farming enterprise depends on climate, topography, fertility, and the constraints these factors place on potential pasture and animal production at a specific location. Modifications to the descriptions of landscape areas note the recent increase in conversion of sheep and beef farms to dairying, plus the dramatic increase in viticulture in the South Island (Figure 15).

Within pastoral systems, about 55% of improved pastures are flat to rolling (slope 0-15°). A further 13% are hill country (16-20° slope) while the remaining area is classified as steep hill or high country (>21° slope) (Hodgson et al., 2005). There are nine broad farm classes used to classify ruminant livestock production systems in New Zealand (section 4). Generally, hill and high country farm systems (Farm Classes 1-4, Section 4) include valley bottoms and/or alluvial terraces so at least 5-10%, or more, of these properties can be cultivated.

Table 7. Dominant land use and selected land cover of New Zealand in 2004 (Ministry for the Environment, 2007).

Land-use classes

Hectares

Percentage of total land area (%)

Dairy

1 879 600

7.0

Intensive sheep and beef

3 841 100

14.3

Hill and High country sheep and beef

4 072 100

15.2

Deer

249 700

0.9

Other animals (goats, pigs, poultry, alpaca, emu, ostrich etc)

64 900

0.2

Ungrazed

659 800

2.5

Urban

203 600

0.8

Planted forest

1 957 000

7.3

Arable & Horticulture

43 460

0.2

Land-cover classes

   

Tussock

2 645 200

9.9

Native forest

6 567 200

24.5

Rivers, lakes, snow, and ice

2 094 200

7.8

Scrub

2 543 600

9.5

Total

26 821 460

100.0

Note: The “Arable & Horticulture” category includes cereals, fruit, vegetables and floriculture


Figure 15. Major uses within the 14 landscape areas (Modified from O'Connor, 1993).
[Click to view full image]

Arable and horticultural production
Topography is a major constraint to the area available for arable cropping, vegetable and horticultural enterprises. The Waikato landscape province has the highest proportion of high value soils suitable for food production followed by Southland. Canterbury has the most flat land but its use for arable crops is restricted because many soils are stony and have poor water holding capacity.

Over the last decade, greater diversification of land use has been evident, especially for horticultural land. As an example, the area of land in vineyards increased by 28% from 1997 to 2002 with large areas converted in Gisborne and Marlborough (Figure 16) with additional expansion into parts of Canterbury and Otago. Table 8 shows the area harvested (ha) for the year ending 30/6/2007 of selected outdoor vegetable, fruit, major cereals and herbage seeds (Department of Statistics, 2007).
Figure 16. Vineyards Wairau Valley, Marlborough (Photo: W.R. Scott).

Table 8. Area harvested (ha) of the selected outdoor vegetable, fruit, cereal and herbage seed crops for the year ending 30/6/2007 (Department of Statistics, 2007).

   

Area harvested (ha)

Crop

 

North Island

South Island

New Zealand

Vegetables

Broccoli

1 624

623

2 247

 

Cabbage

598

171

768

 

Carrots

684

635

1 320

 

Cauliflower

648

212

860

 

Green beans

66

658

724

 

Lettuce

1 134

175

1 309

 

Tomatoes (outdoor)

734

23

757

Fruit

Kiwifruit

12 632

618

13 250

 

Wine grapes

8 303

21 313

29 616

 

Apples

6 004

3 244

9 247

 

Pears

357

337

694

 

Stone fruit

1 077

1 216

2 294

 

Berry fruit

270

431

1 222

 

Citrus

453

9

1 834

Cereal and Seed

Wheat

1 737

38 801

40 538

 

Barley

5 772

45 710

51 481

 

Oats

147

5 626

5 773

 

Herbage seeds

424

26 904

27 329

 

TOTAL

42 664

146 706

191 263

Note: Data may not sum due to suppression of confidential data. “Stone fruit” includes peaches, nectarines, plums, cherries and apricots; “Berry fruit” includes: raspberries, strawberries, boysenberries and blueberries; “Citrus” includes oranges, lemons, grapefruit, mandarins and tangelos.


4. RUMINANT LIVESTOCK PRODUCTION SYSTEMS

New Zealand is recognised for its year round grazing systems with a heavy reliance on perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pastures. Livestock systems are pasture based with forage crops and/or conserved feed used to fill in periods when pasture supply is below animal demand. The distance between New Zealand and its main export markets, combined with an environment suitable for pastoral production, has resulted in a focus on efficient sheep, beef and dairy production systems (Hodgson et al., 2005). Table 9 shows the change in stock numbers from 1994-2007.   In 1996 there were over 66 000 farms of which 25% were dairy farms, 36% were sheep and beef, 5% had mixed livestock, 17% were horticultural enterprises, 2% cropping and 15% allocated to the category “Other” which includes small (0.5-20 ha) “lifestyle” blocks and the equine industry.

Table 9. Total livestock numbers (M) from 1994 to 2007 for the main classes of ruminant livestock commercially farmed in New Zealand (Department of Statistics, 2009b).

Year

Beef cattle

Dairy cattle

Sheep

Pigs

Deer

1994

5.05

3.84

49.47

0.42

1.23

2002

4.49

5.16

39.57

0.34

1.65

2003

4.63

5.10

39.55

0.38

1.69

2004

4.45

5.15

39.27

0.39

1.76

2005

4.42

5.09

39.88

0.34

1.71

2006

4.44

5.17

40.08

0.36

1.59

2007

4.39

5.26

38.46

0.37

1.40

Ruminant livestock systems in New Zealand are based on differences in environment, soil fertility, pasture and animal production levels and the main farming operation. There is a high level of integration between production systems with feed sources and livestock frequently moved between them to overcome regional feed deficits and unseasonal weather events.

Table 10 compares the environmental and farm structure differences in the eight farm classes used by Meat & Wool New Zealand Ltd (Matthews et al., 1999; Hodgson et al., 2005) plus a ninth class to describe dairy farms. Descriptions of each farm class follow.

Table 10. Sheep and cattle farm structure for an average farm separated by farm class. Data for rainfall, steep land, number of farms and stock units (s.u.) as sheep were sourced from 1996 data (adapted from the New Zealand Meat and Wool Board Economic Survey, 1997) (Matthews et al., 1999). Data for effective area, stock units per hectare, wool yield, lambing, calving and fawning percentages are for the 2007/08 season (Meat & Wool New Zealand Economic Service, 2009b) and information for dairy systems is for 2007/08 (DairyNZ and LIC, 2009).

Farm Class

Rainfall (mm)

Steep land
(%)

No. farms

Effective area (ha/farm)

Labour (persons/farm)

stock units1 (s.u./ha)

s.u. as sheep (%)

Wool (kg/s.u.)

Lambing (%)

Calving (%)

Fawning (%)

1)  South Island
High Country

739

82

250

10 660

3.3

1.1

81

4.7

85

81

87

2) South Island Hill Country

766

61

900

1 600

1.9

4.0

76

4.7

114

85

85

3)  North Island Hard Hill Country

1 520

77

1 550

790

1.9

8.7

60

4.5

115

76

79

4)  North Island Hill Country

1 408

45

4 500

400

1.6

10.2

56

5.1

120

80

75

5)  North Island Intensive Finishing

1 190

15

2 900

270

1.4

10.1

52

4.6

120

84

-

6)  South Island Finishing Breeding

780

23

4 100

450

1.7

9.3

82

5.0

128

88

78

7)  South Island Intensive Finishing

927

14

2 600

240

1.4

12.5

94

5.3

148

86

100

8)  South Island Mixed Finishing

685

0.7

900

355

2.6

7.5

76

5.0

127

71

-

9)  Dairy

>1 500

0

11 436

126

 

2.83a

 

307 b

-

74 c

-

Notes: dairy information is for the 2007/08 season. Rainfall for dairy systems includes irrigated properties in lower rainfall environments a = cows/ha; b = kg milksolids/cow; c = total number of calves born alive (3.5 M) divided by the total number of dairy cows and heifers in calf, in milk or empty but intended for milk production (4.7 M) as at 30/6/2008.

[1] s.u./ha = stock unit/ha. Stocking units are standardised rates which allow direct comparison of stocking rate regardless of stock class. A stocking rate of 1 s.u./ha is equivalent to one breeding ewe which rears one lamb. Feed allocation is 550 kg DM/y with an average metabolisable energy (ME) content of 10.5 MJ ME/kg DM. The allocation includes lamb feed consumed to weaning at 14 weeks. Ewes weighing 65 kg/head weaning 120% are equivalent to 1.2 s.u./ha. A 300 kg dairy cow with a milksolids yield of 280 kg is equivalent to 6.3 s.u; a 400 kg beef cow weaning 83% is equivalent to 4.4 s.u.; and an adult male red deer is equivalent to 2.1 s.u.. Stocking rate of a farm is usually based on the number of stock wintered on a farm. Specific details can be sourced from the Lincoln University Farm Technical Manual (Fleming, 2003).

South Island high country
The South Island high country farms systems are extensive and dominated by high altitude tussock grassland (Figures 17 and 18). Improved pastures are limited to flat and rolling land on a limited area of valley bottoms and old river terraces. Approximately 80% of feed produced comes from the 20% area of improved pastures on the property (Matthew et al., 1999). Properties can range in size from 3 000 to 40 000 ha. Traditionally, these are fine wool producing properties. The average farm size for farms in this class is 10 660 ha (Table 10). Stocking rates are generally low (1 s.u./ha). but the contribution of improved pastures is marked. Carrying capacity of these properties is strongly influenced by the area of improved pastures present which may carry up to 4 s.u./ha. Consequently, farms with larger areas of improved pastures may have a higher carrying capacity.

Steep hill and mountainous terrain combined with a short growing season means annual pasture production is low and intensification may not be economically viable. Pasture production on high country varies depending on position in the landscape and level of pasture improvement. For example, in a 600-900 mm/yr rainfall environment production from unimproved pastures ranges from 0.3-1.0 t DM/ha/yr; improved pastures on shady faces can yield 2.5-5.5 t DM/ha/yr; on sunny faces improved pastures can produce 2.0-5.0 t DM/ha/yr. Improved pastures on flat land (terraces and valley bottoms) can yield between 4.0-10.0 t DM/ha/yr (Matthews et al., 1999). Farms are stocked with a combination of merino sheep, beef cattle and deer, all of which are seasonally set stocked. Ratios between stock classes are altered depending on the season and commodity prices.

Historically, the main source of revenue has been wool (60-70% of farm income) but recent low wool prices have resulted in a shift to store lamb and calf production to increase farm income. Currently farm incomes are 51% from wool, 21% from lamb and 15% from beef (Figure 19) with a gross farm income of NZ$ 59/ha. Some farms have also run deer to sell weaners for finishing (venison) and for immature antlers (velvet) from a stag herd.

Appropriate stock management in winter and spring is essential in these systems due to the short growing season and harsh environmental conditions for production. Frost can occur throughout the year and snow may lie at altitudes above 1 000 m for several months. Within a grazing area, pasture production is highly variable because of variations in slope, aspect and altitude. In winter months animals grazing at high altitude may be lost due to snow if appropriate measures are not taken to protect vulnerable stock. Long (4-5 month), cold winters mean the active growing season is short. Therefore, these properties are highly reliant on forage crops (e.g. swedes, Brassica napus) and conserved feed from lucerne (alfalfa; Medicago sativa) or pasture based hay or silage, which is generally grown in spring on the limited flat land available in river valleys and old river terraces. These flatter areas are well subdivided and break fenced for feeding out during critical periods when feed demand exceeds supply.

Figure 17. An extensive South Island high country property in the Lindus Pass with native tussock grasslands
(Photo: W.R. Scott).
Figure 18. Sheep grazing tussock grasslands near Lake Tekapo in late winter/early spring
(Photo: W.R. Scott).
Figure 19. Percentage of gross farm revenue per hectare from different sources for a South Island High country property (Farm Class 1) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

Previously, about 80% of land grazed by high country farms was under pastoral lease from the Crown (i.e. owned by the government). These properties have been the subject of recent “Tenure Review” (see below).  The process negotiates for landscapes of value to the nation. Large areas of higher altitude tussock grasslands have been returned to government management (Department of Conservation) and withdrawn from grazing. In the current review cycle higher value is placed on the lower altitude landscapes within this property class. In return, lease holding farmers are able to freehold lower altitude land which is less vulnerable to erosion.

Rangeland on these properties is dominated by native tussock species. These include: Chionocloa spp. (tall tussock or snow grass), Festuca novae-zelandiae (fescue or hard tussock) and Poa cita (silver tussock) interspersed with introduced low yielding but persistent browntop (Agrostis capillaris). Invasion by Hieracium species over the last 50 years has reduced the productivity of unimproved tussock grasslands. The most prostrate of these perennial daisies, Hieracium pilosella, has the greatest effect on productivity. Introduced woody weeds, gorse (Ulex europaeus), broom (Cytisus scoparius), sweet brier (Rosa rubiginosa) and conifers (wilding Pinus spp. from exotic forestry plantations) are also difficult to control under these extensive grazing systems.

South Island hill country
Pasture production is constrained by low temperatures in winter and by soil moisture deficits which develop in late spring and summer. This is compounded by shallow, weakly developed soils that dominate on the eastern foothills of Marlborough, Canterbury and Otago. Unreliable pasture growth in summer months reflects seasonal variation in the rainfall distribution combined with high evapotranspiration and low soil water holding capacity due to a high proportion of stones within the profile and/or shallow depth to underlying gravels. Annual pasture production is 1.0-6.0 t DM/ha/yr (Matthews et al., 1999).

Properties within this land class (Figure 20) produce wool and breed lambs and cattle which are then sold to lowland intensive finishing properties (Farm Class 6). Mid micron sheep (merino x coarse wool cross breeds or Corriedale) are the dominant breeds and they graze modified tussock grasslands. Typically, about 75% of the stock wintered are sheep and 25% are beef cattle at about 4 s.u./ha. These properties are being forced to intensify as dairy conversions displace the intensive sheep and beef finishing properties on the more fertile lowland plains. The gross revenue for farms in this class in 2007/08 was NZ$ 211/ha and contributions from different sources are shown in Figure 21.

Figure 20. South Island hill country property near Hawarden (North Canterbury) showing improved pastures in foreground on cultivatable land and lower producing mixed species pasture on steeper hill country in the background 
(Photo: W.R. Scott).
Figure 21. Percentage of gross farm revenue per hectare from different sources for a South Island Hill country property (Farm Class 2) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

Low input pastures are a mix of low fertility tolerant and lower yielding pasture species which include Notodanthonia spp., browntop, sweet vernal (Anthoxathum odoratum), silver tussock, Yorkshire fog (Holcus lanatus), adventive annual legumes such as suckling (Trifolium dubium) and haresfoot (T. arvense) clovers. Development of improved pastures, which includes grass/legume pastures, areas of lucerne for hay and brassicas for winter feed, depends on the level of investment for improvements. Soils tend to be naturally acidic (pH 4.5-5.5) and fertility can be improved by the application of lime and superphosphate fertilizers on river flats, terraces and easier lower slopes. Improved pasture species include perennial ryegrass, cocksfoot (Dactylis glomerata) white and subterranean (T. subterraneum) clovers. Supplements (predominantly brassicas) are grown on cultivatable land to provide winter feed. Clovers can be introduced to hill slopes by aerial broadcasting of inoculated seed followed by heavy stocking with sheep and cattle to trample in the seed.

North Island hard hill country
These properties are steep hill country (>16° slopes, see Figure 22) with low fertility soils on the east and west coasts and Central Plateau of the North Island. Properties were cleared from native forest in the late 19th Century by burning and broadcasting seed. Further pasture improvement was possible from 1950 with the widespread use of aerial topdressing of superphosphate fertilizer and oversowing with improved pasture species, particularly white clover. These low fertility soils are maintained by regular aerial topdressing with lime and superphosphate when this is financially viable but applications cease if farm returns drop in relation to fertilizer prices. Woody weeds such as gorse and manuka (Leptospermum scoparium) can reduce the productive grazing area and weed control is made difficult by the terrain. Woody weed reversion can be avoided by maintaining intensive grazing management through subdivision.

Annual rainfall for farms in this class is usually >800 mm and temperatures allow year round pasture production although lower rates occur in winter months. Steep hills are prone to soil erosion by mass movement following high intensity, saturating rain events and this is compounded when pastures are overgrazed.

Pasture yields are 2.0-6.0 t DM/ha/yr and properties are stocked at about 8-9 s.u./ha with dual purpose sheep breeds and beef cattle (about 60:40 sheep:beef s.u.). The majority of farm income is from the sale of store lambs, wool, cast-for-age ewes and beef weaners (Matthews et al., 1999; Hodgson et al., 2005). In the 2007/08 season, 63% of total gross farm income (NZ$ 351/ha) was from wool and sheep with a further 31% from cattle (Figure 23).
Figure 22. Example of a North Island hard hill country property visited by Lincoln University students on a field trip
(Photo: W.R. Scott).
Figure 23. Percentage of gross farm revenue per hectare from different sources for a North Island Hard Hill Country property (Farm Class 3) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

Low fertility, low producing species which include browntop, Yorkshire fog, sweet vernal, crested dogstail (Cynosurus cristatus), white clover and adventive annual legumes dominate pasture production. Significant fertility transfer of nitrogen, phosphorus and sulphur (Gillingham and During, 1973; Saggar et al., 1990) can occur on a micro-scale from slopes to sheep tracks and camps (section 5) where perennial ryegrass and white clover can dominate.

North Island hill country
These properties are smaller in area than those on hard hill country and are more productive per unit area. Soils are moderate to high fertility resulting from lime and fertilizer inputs over time. Feed deficits may occur in summer months as pasture production is compromised when summer soil moisture deficits develop.

Lower slopes and flat land are easily cultivated to introduce improved pasture species (Figure 24). Predominantly these are perennial ryegrass and white clover but subterranean clover and cocksfoot use is also widespread. In stock camps high fertility weed species dominate. These include Californian (Cirsium arvense), scotch (C. vulgare) and nodding (Carduus nutans) thistles, barley grass (Hordeum murinum) and nettle (Urtica urens). Nitrogen deficiency often compromises potential pasture production and this is addressed by management to encourage pasture legumes and some use of inorganic N fertilizer when it is economic.

Annual pasture production is 5.0-8.0 t DM/ha/yr (Matthews et al., 1999) from improved species and stocking rates can be 10+ s.u./ha. A high proportion of stock are sold in forward store or prime condition. Income from cattle accounted for 38% of total gross farm income (NZ$ 550/ha) in 2007/08 and a further 41% was from sheep production (Figure 25).

Figure 24. Example of a North Island hill country property
(Photo: W.R. Scott).
Figure 25. Percentage of gross farm revenue per hectare from different sources for a North Island Hill country property (Farm Class 4) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

North Island intensive finishing systems
This farm class can be found throughout the North Island. Farms are high fertility flat to rolling properties that produce 10.0-16.0 t DM/ha/yr from predominantly perennial ryegrass/white clover pastures (Figure 26). These persist for 10-15 years before they undergo renewal. Endophyte status (see section 5) of the perennial ryegrass is determined by the requirements of the systems and the number of life cycles pests such as Argentine stem weevil (Listronotus bonariensis) complete during a year. Recently, novel endophytes such as AR1 and AR37 have been introduced to protect against pasture pests without causing the animal health issues (e.g. ryegrass staggers) associated with use of wild type endophyte infected ryegrass. Leaf turnips are sown as part of the pasture renewal program (see section 5) and provide supplementary feed during periods of summer or winter feed deficit.

Stocking rates may reach 12-13 s.u./ha with the majority sold in prime condition to the freezing works. In favourable environmental conditions pasture production allows purchase and finishing of replacement ewes and store lambs obtained from surrounding hill country farms (Farm Classes 3 and 4). Income is from a combination of beef (including bull beef from the dairy industry) and prime lamb production. Gross revenue was NZ$ 799/ha in 2007/08. Providing grazing for dairy cattle and cash crops provided about 13% of gross farm income (Figure 27).
Figure 26. Example of a North Island intensive finishing farm
(Photo: W.R. Scott).
Figure 27. Percentage of gross farm revenue per hectare from different sources for a North Island Intensive Finishing property (Farm Class 5) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

South Island finishing-breeding farms
Sheep and beef finishing and breeding farms may be >300 ha in size and this is the dominant farm class in the South Island. Properties are intensively managed for finishing and breeding stock. Pastures may be irrigated in drier areas.

Perennial ryegrass/white clover pastures dominate under irrigation while specialist forages such as lucerne and brassicas are sown to ensure the supply of high quality feed particularly on the dryland properties exposed to summer moisture limitations. Perennial ryegrass is generally infected with wild type or a novel endophyte to ensure pastures persist due to combined effects of pest load and periodic exposure to drought. Cocksfoot is more suited to these environments but yields can be below potential due to nitrogen deficiency, which can have a greater effect on total annual pasture production than the periodic summer drought (Mills et al., 2006). In dryland systems, where soil water stress compromises pasture production, white clover also fails after loss of the taproot 12-18 months after sowing. Weed species include browntop, twitch (Elymus repens), barley grass, vulpia (Vulpia spp.), dock (Rumex obtusifolius) and thistles. Pastures are renewed at 6-10 year intervals depending on the level of weed and pest infestation and the need for land to grow winter forage crops. Typically, about 10% of the property is renewed annually to maintain production of high quality forage and ensure winter feed supply. Lucerne can represent 30-40% of the effective farm area and cultivars need to be resistant to blue green aphid (Acyrthosiphon kondoi) and resistant/tolerant of stem nematode (Ditylenchus dipsaci) to ensure production and persistence. Lucerne stands are rotationally grazed to ensure optimum animal performance and stand persistence, and may be conserved as hay or silage.

Perennial ryegrass based pasture yields are generally 7.0-10.0 t DM/ha/yr in the Canterbury and Otago regions. This increases in years with above average summer rainfall. This allows stocking rates on dryland properties to be maintained at 9-10 s.u./ha and replacements are generally bred on-farm. Irrigated pastures may produce 15.0 t DM/ha/yr and carry up to 20 s.u./ha.

Of the NZ$ 670/ha gross income almost half (Figure 28) is generated from sheep production and income may be supplemented by using a limited farm area for vegetable or arable cash crops sown for either processing or seed production. Conversion of suitable sheep and beef farms to dairying occurs when irrigation is available and commodity prices provide a financial incentive.

Figure 28. Percentage of gross farm revenue per hectare from different sources for a South Island Finishing-Breeding property (Farm Class 6) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

South Island intensive finishing farms
These farms are mostly found in summer safe environments in Southland (Figure 29) and parts of Otago where sufficient summer rainfall precludes severe droughts but winters may be severe. Typically, in these farm systems, about 85% of gross farm income is from sheep, 7% from cash crops and about 2% from beef cattle (Matthews et al., 1999). However, in 2007/08, farms in this class actually generated gross farm incomes of NZ$ 1091/ha of which 7% was from cattle and only 2% from cash crops (Figure 30). High production rates (>65 kg DM/ha/d) occur consistently from late spring and through summer with annual yields of 10.0-15.0 t DM/ha/yr capable of carrying 12 s.u./ha. The climate provides reliable rainfall year round but cool temperatures restrict winter pasture growth. Nil endophyte perennial ryegrasses are used as the basis for pasture mixes with white clover because pest incidence is reduced in cooler climates. This avoids potential for animal heath issues. Other pasture species used in these systems include annual and hybrid ryegrasses, timothy (Phleum pratense), red clover (Trifolium pratense) and chicory (Cichorium intybus). Weed species include browntop, crested dogstail and Californian thistle. Pasture renewal intervals depend on management strategies but are usually at least 10 years. Forages such as bulb brassicas (swedes) are essential to provide winter feed (Figure 31). These are sown in late spring to accumulate 15.0-20.0 t DM/ha over summer/autumn before being grazed off behind an electric fence in winter. This outdoor feed supply in the coldest regions of New Zealand means animals are not housed. Equally, the perennial grass pastures are grazed hard in late summer before being left to accumulate pasture cover in autumn that may also be break-fed in winter months (Figure 32), or utilised in spring for lambing.
Figure 29. South Island intensive finishing property near Gore. Note areas sown in brassica left and central mid distances for winter feed
(Photo: W.R. Scott).
Figure 30. Percentage of gross farm revenue per hectare from different sources for a South Island Intensive Finishing property (Farm Class 7) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).
Figure 31. Winter grazing of a swede crop in Southland
(Photo: W.R. Scott).
Figure 32. Example of ‘all grass wintering’ in Southland. Break fencing ensures development of a feed wedge and back fencing is important when re-growth production is expected
(Photo: W.R. Scott).

South Island mixed cropping and finishing farms
These farms are mainly in Canterbury on flat land with deep soils. Irrigation is usually available. The main crops are cereals; wheat (Triticum aestivum), barley (Hordeum vulgare), oats (Avena sativa), herbage seed (ryegrasses, white clover (Figure 33), cocksfoot and tall fescue (Festuca arundinacea), vegetable seeds and process crops such as peas (Pisum sativum), beans (Phaseolus vulgaris); potatoes (Solanum tuberosum) and carrots (Daucus carota). Many run a breeding sheep flock and/or finish bought in lambs which fit into the crop/pasture rotations.

About 70% of gross farm income is derived from grain and small seed production. Revenue sources and contributions to farm income per hectare for 2007/08 (NZ$ 2 348/ha) are shown in Figure 34. The remainder is split between stock finishing and process crops. In these systems specialist finishing pastures of lucerne or red clover, chicory and annual (Lolium multiflorum) or hybrid ryegrass may be used to maximise animal liveweight gains. Permanent pastures are uncommon because the pasture phase is part of the cropping rotation used to increase soil organic matter levels and restore soil structure.

Figure 33. Example of a white clover herbage seed crop grown in Canterbury
(Photo: W.R. Scott).
Figure 34. Percentage of gross farm revenue per hectare from different sources for a South Island Intensive Finishing property (Farm Class 7) for the 2007/08 season
(Meat & Wool New Zealand Economic Service, 2009b).

Dairy farms
Most dairy farms are in ‘summer safe’ areas which include South Auckland, Waikato and Taranaki in the North Island and Southland and the West Coast of the South Island which have a favourable growing environment. These regions usually experience >1500 mm of annual rainfall and periods of water stress are uncommon. There has been recent expansion in dairying (see below) into traditional sheep and beef regions on the east coast of the South Island where irrigation is available (Figure 35). This is due to higher returns from milk than from meat and wool in recent years. These systems may need to provide 450 mm of irrigation water to overcome PSMD in summer.

Dairy systems are high input, and high fertility farms which are intensively managed. Perennial ryegrass pastures dominate with some white clover. Supplementary feed is required (pasture and maize (Zea mays) silage, palm kernel, brassicas) for winter months to complement perennial ryegrass pasture production curves. In the North Island turnips (Brassica rapa) and maize (for silage) dominate supplementary feed which may also be used to supplement pasture in summer. In the South Island, kale (B. oleracea spp. acephala) is the dominant forage crop for winter grazing. Dry stock are often wintered on other properties (e.g. mixed cropping properties described in Farm Classes 6 and 8) off the “milking platform”, particularly in the South Island.

Figure 35. Dairy cows grazing irrigated perennial ryegrass dominant pasture on the Lincoln University Dairy farm, Lincoln, Canterbury
(Photo: W.R. Scott).

Ruminant sector demographics, products and exports

The sheep industry
New Zealand sheep meat has been exported to international markets since 1882. It accounts for 6% of global production but 38% of international sheep meat trade (2006/07). The majority is destined for markets in the European Union. Prime lambs tend to receive the highest prices, and are sold before Christmas to meet market demand. A benefit of this for those farmers that can procure lambs at this time is that they are sold prior to summer dry conditions which compromise pasture production on the east coast of both islands. Currently the average carcass weight is 17.7 kg/hd (Meat & Wool New Zealand Economic Service, 2009a) and the majority of lambs are slaughtered at ~100 days of age.

Total sheep numbers (Figure 36) have decreased from 70.3 million in 1982 to ~50 million in 1994 (MAF, 2009) and declined further to an estimated 34 million in 2008 (Department of Statistics, 2009b). This decrease represents the dynamic nature of the livestock industry which has responded to low sheep meat prices and an east coast drought. The drought reduced the national lambing percentage by 5.3% to 113% because ewes were in a poorer condition than usual at mating. Changes in land use included conversion of sheep farms to dairying, viticulture and cropping which offered higher returns than meat. Breeding ewe numbers decreased almost 10% in 2008, and the greatest reduction (almost 15%) was in Marlborough/Canterbury (Meat & Wool New Zealand Economic Service, 2009a). Dairy conversions occurred on 330 sheep and beef properties in 2008 which displaced 1.3 M sheep and beef stock units. Total conversions in 2008 were second only to the 360 properties converted in 1996/97. In contrast, only 70 farms underwent dairy conversion in 2007.

Despite the >30% decline in sheep numbers since 1990 (MAF, 2009), total national lamb meat production has increased by 12% over the same period. This reflects improvements in on-farm management practices, genetic gains for animals, higher quality pastures, animal and pasture based research and uptake of new knowledge by pastoral farmers.

Figure 36. Total sheep and breeding ewe population changes in New Zealand between 1994 and 2008
(Meat & Wool New Zealand Economic Service, 2009a).

In June 2000 it was estimated that 58% of all sheep were the dual purpose Romney. This was the dominant breed in the North Island and south of the South Island. In Canterbury, Marlborough and Otago the main breeds were Corriedale and Half breed dual purpose sheep which accounted for 6% and 4% of the national flock. South Island high country properties favour merinos (7% of all sheep) for their fine wool production. The other two major breeds are the Coopworth and Perendale which accounted for 10% and 7% of the national flock. The remaining 8% consists of crossbreeds, composites, Texel, Suffolk, Borderdale, Dorper, Poll Dorset and others. As producers move towards dual purpose flocks, genetics from Texel, Finn and East Friesian are being used to increase fertility and the meat production potential of the existing Romney, Perendale and Coopworth based flocks.

Half of New Zealand lamb exports in 2007/08 (volume) and 64% of lamb export receipts (value) were to the European Union. Of this, 30% was chilled lamb and 70% frozen. For the 2007/08 year (Sept) lamb exports accounted for NZ$ 2.52 billion (Meat & Wool New Zealand Economic Service, 2009a).

Wool
New Zealand wool is used in the production of 45% of the world’s wool carpets (Meat & Wool New Zealand, 2008). In New Zealand fleece weights are 4.5-5 kg/hd (clean) compared with a global average of 1.2 kg/hd. In 2006, 14% of global wool production was from New Zealand and this indicates that 89% of all New Zealand wool was exported. Of this, 7% of the wool sold at auction was fine (<24 micron), 6% was medium (25-32 micron) and 87% was strong wool (>32 micron). Clean wool exports totalled NZ$ 613 M for the 2007/08 year, and the price was at its lowest in more than 20 years (Meat & Wool New Zealand Economic Service, 2009a). The majority of New Zealand wool is sent to China (37 300 t clean) which included >40% of the total fine wool. A consequence of the decrease in wool prices since 2005/06 (Figure 37) has been a shift by farmers towards composite sheep breeds to increase income from meat production with the wool component contributing less to total farm income.

Figure 37. Change in wool price and quantity of wool produced between 2003/04 and 2008/09
(Meat & Wool New Zealand Economic Service, 2009a).

The Beef Industry
Over 99% of beef produced in NZ is grass fed and about 70% of the national beef herd is in the North Island. Bull beef is mainly sold for slaughter at 260-300 kg carcass weight (500-580 kg liveweight/hd) when stock are 14-18 months old (Hodgson et al., 2005).

In June 2008, total beef cattle numbers were 4.3 M which was a 3.2% decrease from June 2007 (Figure 38) and 31% of these were breeding cows and heifers. Over 2.0 M head are slaughtered annually with 200 000 t of beef and veal meat exported to North America (54% of total beef exports) and 100 000 t to North Asia (28%). At 30 June 2008, the main beef breeds were Angus (~20%), Friesian (~23%), Angus/Hereford (8%) and Hereford (~8%) and mixed breed (32%).

About 70-80% of all beef cattle are farmed in the North Island (Farm Classes 3, 4 and 5). In Taranaki/Manawatu the 5.6% decrease in beef cattle numbers between 2007 and 2008 was a result of drought and dairy conversion whereas beef cattle numbers on the east coast of the North Island increased 5.3%. In the South Island, dairy conversion of finishing properties in Southland and Canterbury resulted in a 1.2 M head reduction between 2007 and 2008. This decreased weaner cattle numbers by almost 30% in Southland. However, breeding cow numbers increased 6-8% in Southland and Otago. The majority of the increase in breeding cow numbers occurred on Farm Class 2 (South Island Hill Country) properties in Otago, Farm Class 6 (South Island Finishing-Breeding) in Southland and retention of weaners on Farm Class 1 (South Island High Country) land in Marlborough/Canterbury regions.

Figure 38. Changes in the total number of beef cattle and the number of breeding cows (subset of total herd number) in New Zealand between 1994 and 2008
(Meat & Wool New Zealand Economic Service, 2009a).

The Deer industry
New Zealand is now the major exporter of deer products globally and accounts for about 50% of the worldwide farmed deer numbers. The major product is venison meat (~84%) followed by antler velvet (10%) and other co-products including hides and leather with 90% of all venison produced being exported. The majority of venison produced is sent to European markets while velvet and co-products are exported to Asia. Animal welfare regulations on the removal of velvet are strict. Only veterinarians or farmers who have been appropriately trained may administer the local anaesthetic and remove immature antlers.

The NZ Deer Industry Industry was developed from aerial capture of wild red deer from the South Island high country. Deer were initially released in the Southern Alps and foothills of the Canterbury Plains in the mid 1800s for sport. Lack of predation and a suitable environment resulted in significant increases in the feral population. These animals are considered pests that destroy native vegetation. Aerial eradication programmes were used to control numbers in the wild and export of feral venison began in the 1960s.

In the 1970s live capture of feral red deer was initiated and these bloodlines form the basis of the deer industry. Red deer account for over 85% of the national herd with the remainder from Wapiti (Elk; Cervus canadensis) and red deer/wapiti crosses. A small number of fallow deer (Dama dama) are also commercially farmed. Genetic improvements have been made through the import of genetic material from Eastern Europe, the UK and North America.

The total number of farmed deer decreased 28% between 2005 and 2008 to 1.2 M (Figure 39) in response to product prices. About 70% of farmed deer are in the South Island (Department of Statistics, 2009b). In 2002, the total export value of the deer industry was NZ$ 375 M.

Deer farming occurs in a range of farming systems from small herds on lifestyle blocks (10-20 ha) to large herds grazing on extensively managed high country farms (Farm Class 1). In these larger farming systems deer are usually part of a diversified stock portfolio which includes sheep and beef cattle (Deer Industry New Zealand, 2009). Farming systems may focus on 1) breeding, 2) venison finishing or 3) velvet production, but commonly farms run a combination of operations to spread the economic risk. In 2002/03, deer contributed >50% of farm revenue on 2 300 farms nationwide and these farms accounted for 63% of the farmed deer population (Ministry of Agriculture and Fisheries, 2009b).

The red deer gestation period is ~233 days with fawning in November/December. This timing does not match traditional ryegrass/white clover pasture production curves which peak a month earlier in most dryland systems. Feed demand by this class of stock is also highly seasonal. Consequently, the majority of farmed deer sold for venison are slaughtered at 12-15 months of age by which time they have achieved 50-60 kg carcass weight. Target liveweights for commercially farmed stags and hinds of different breeds are presented in Table 11 . Velvet production ranges from 1 kg/head from young animals (2 years age), 2.5 kg/head from stags aged 5-8 years) with a 4.5 kg/hd maximum (Hodgson et al., 2005). 

Most herds graze perennial ryegrass based pastures but specialist pastures of herbs and legumes such as chicory, red clover and lucerne are used to promote high liveweight production. During periods of feed deficit hay, silage and grain may be fed out to maintain feed supply.

Figure 39. Total farmed deer numbers at 30 June between 1981 and 2008 in the North and South Islands of New Zealand. Note: data were not collected in 1997, 1998, 2000 and 2001
(Department of Statistics, 2009b).

Table 11. Target liveweights (kg/head) at different ages for stags and hinds of commercially farmed deer breeds in New Z ealand (Fleming, 2003).

Class

Breed

4 months (weaning)

9 months
(winter end)

16 months
(end summer)

2 years

Mature (summer)

Stags

NZ Red

  53

  67

109

145

200

 

Half bred
Wapiti/red

  75

107

160

180

300

 

Canadian Wapiti

140

168

260

320

400

Hinds

NZ Red

  48

  60

  85

  95

100

 

Half bred
Wapiti/red

  66

  95

130

180

220

 

Canadian Wapiti

120

150

220

270

330

The Dairy industry
New Zealand’s dairy industry has expanded rapidly over the last 20 years. Traditionally, dairy farming was restricted to ‘summer safe’ flat to rolling land in the west of the North Island where mean annual rainfall is ≥2 000 mm/yr. Recent expansion into high risk regions that receive 600-1 000 mm rainfall has occurred in Canterbury, Otago and the eastern North Island. These regions are highly reliant on access to irrigation in summer months. The conversion of sheep/beef properties to dairy has been fuelled by an increase in dairy commodity prices as international demand has increased. Dairy products now account for 37% of the countries merchandised agriculture and forestry exports With the increased potential incomes from dairy products, land prices have increased dramatically from NZ$ 5 013/ha in 1988 to NZ$ 28 035/ha in 2007 (DairyNZ and LIC, 2009).

New Zealand dairy systems are based on year round outdoor pastoral grazing. Direct grazing contributes about 90% of the animal feed demand and means production costs are low by international standards (Hodgson et al., 2005). When pasture production is insufficient to meet stock demand, due to low winter temperatures, or summer drought conditions, or when pasture quality is insufficient to meet the animals’ energy requirements, supplements such as hay, silage, concentrates and/or forages fed in situ are included. The primary pasture is perennial ryegrass/white clover which is high producing in environments with adequate rainfall (annual and seasonal) or where there is access to irrigation. Dairy systems are intensively managed with rotational grazing, twice a day shifts (which are often back fenced) which coincide with milking. Recently some farmers have begun ‘once a day’ milking programs.

Farms are generally run as either 1) owner operated 2) contract milk or 3) share-milking farm structures. Owner operators account for 63% of the national herd (DairyNZ and LIC, 2009). The majority of owner operator and contract milk structures dominate with smaller herd sizes (<200 cows). Almost 80% are based in the North Island. Share-milking is a farm structure in which there is a partnership between a farmer (landowner) and a share-milker (herd owner). Partnerships vary depending on the resources contributed by each of the partners. The 50/50 share milking structure accounts for a further 22% of the national herd while 10% are managed under a <20-29% share-milking structure and <2% are >54% share-milkers. Share-milking is the dominant farm operating structure when herd size is 200-449 cows and reflects the inputs necessary to manage larger herds.

The national dairy herd is >4 M milking cows/heifers and has increased by more than 50% since 1992/93. During this time the average herd size has increased from 180 cows/herd to 351 cows/herd while the number of herds has declined by 20% to 11 436 (DairyNZ and LIC, 2009). The average on-farm stocking rate has increased from 2.5 to 2.8 cows/ha and varies regionally from 2.2 cows/ha in Northland to 3.3 cows/ha in North Canterbury.

Herd sizes varied in 2007/08, with ~3% having <100 cows and ~3% having >1000 cows. About 52% of all national herds have 150-349 cows. The majority of dairy farms (79%) are located in the North Island of which 32% are in the South Auckland/Waikato region and 16% in Taranaki. Farm sizes in the South Island (526 cows/herd and 186 effective ha) are larger than those in the North Island (305 cows/herd and 110 effective ha) with the largest average herd size in Canterbury (>700 cows/herd).

Increased production by the New Zealand dairy industry is a reflection of improvements in on-farm management and genetic gain. Over 70% of the national herd undergo herd testing which allows low producing or disease prone (predominantly mastitis) animals to be identified and culled. The best performing stock are then used for breeding. Since 1998/99 the total amount of milk processed from the national herd has increased 40% from 10.6 billion l/yr to 14.7 billion l/yr. Milk solids (MS) production has increased by ~3.9 kg MS/cow/yr from 653 (1992/93) to 934 kg MS/cow/yr in 2006/07. Figure 40 shows the changes in annual milk solids production in New Zealand between 1992/93 and 2008/08 on a per cow and per hectare basis.

Figure 40. Milk solids production per hectare (excludes runoff) and average per cow milk solids production in New Zealand between 1992/93 and 2007/08
(DairyNZ and LIC, 2009).

Main breeds and production differences. In all regions except Taranaki, Holstein-Friesian is the dominant breed and accounts for almost 45% of the national herd. Holstein-Friesian/Jersey crossbreeds account for ~33% (DairyNZ and LIC, 2009). Other breeds include Jersey (14%), Ayrshire (<1%) and “Other” (7%). The Holstein-Friesian dominates because of its higher average milk production (4 043 l milk/cow/yr) which is 12-43% more than the other breeds and consequently gives higher levels of protein (144 kg/cow/yr) and milk solids (318 kg/cow/yr). The average cow is in milk for ~250 days with Holstein-Friesian/Jersey crossbreeds having the highest average milkfat production (176 kg/cow/yr) while Jersey cows have the highest average milk solids (9.75%) and protein (4.03%) content.

Average cow liveweights differ with age and breed with 2 yr old cows having an average weight of 322-405 kg/cow. Across the three main breeds and all age groups (2->10 years) average liveweights range from 385 kg (Jersey) to 487 kg (Holstein-Friesian).

Since 1999/00, over 75% of the national herd has been mated using artificial insemination (AI). Successful AI requires on average 1.25-1.35 inseminations/cow. Bulls may be put out with the herd post AI with 1 bull/75 cows for a period of 4-5 weeks. To maintain a 365 d cycle all cows must be mated about 80 d after calving with a target body score condition of 5.0. The start of calving varies regionally due to environmental conditions. In Northland the start of calving is in mid July compared with early August in the South Island.

Animal health and welfare
Monitoring, prevention and control of disease and disorders in ruminant livestock is critical to the success of New Zealand pastoral farming systems. The impact and spread of many diseases and disorders which can affect production, and thus income, can be prevented by ensuring livestock are provided with feed of adequate quantity and quality to meet their growth and reproductive requirements.

Prevention is more desirable than control. For example, introducing new feed sources slowly allows the rumen to adapt and can reduce the risk of acidosis, bloat, diarrhoea and photosensitivity (Fleming, 2003). Shearing sheep to remove dags (wool contaminated with faeces) reduces potential for fly-strike. Culling of poor performing or susceptible stock is common practice to ensure the genetic structure of the herd/flock is suited to the system and environment.

Fortunately New Zealand’s isolation, border inspection and quarantine measures have ensured that economy crippling diseases such as Bovine Spongiform Encephalopathy (BSE) and foot and mouth disease (FMD) are not present. The Ministry for Agriculture and Fisheries (MAF) has protocols in place to allow rapid containment of any potential outbreak. Hydatids eradication programs have been highly successful and an eradication program for sheep measles which involves dosing working dogs and preventing access to raw sheep meat is in progress.

Parasites
Internal parasites, especially gastrointestinal parasites are a major cause of decreased production, especially in young stock (<20 months). Liveweight gain may be reduced by 50% and wool production by 25% from stock grazing heavily infested pastures. Widespread use of anthelmintics since their release in the 1960s has lead to the development of resistant populations in some areas. Consequently, an integrated approach is required to reduce infestation. This requires grazing grass based pastures with different stock classes (e.g. sheep then cattle), different ages of stock (e.g. production sheep >20 months in age is less affected than younger stock), providing access to ‘safe pastures’ with reduced infestation (e.g. forage crops, hay or silage) plus strategic anthelmintic applications to reduce development of resistant populations.

External parasites are treated with organo-phosphate dips or synthetic pyrethroids and insect growth regulators. Wool withholding periods following treatment range from 60 d for coarse wool breeds to 180 d for fine wool breeds. Prevalence of fly-strike has increased since the Australian green blowfly (Lucilia cuprina) arrived in New Zealand in 1982 but Lucilia sericata, Calliphora stygia and Chrysomya rufifacies also commonly initiate fly-strike. Ensuring diets have adequate fibre (reduced diarrhoea), and removal of faeces contaminated wool (shearing –crutching) are critical to reducing risk of fly strike. Animals which do become fly-blown require immediate treatment and this is highly successful when affected stock are identified early.

Facial eczema
Facial eczema occurs most commonly in grazing sheep but can also affect cattle. It is caused by the saprophytic fungus Pithomyces chartarum which survives in the base of pastures. Ryegrass, cocksfoot, browntop, Yorkshire fog or dogstail grass dominant pastures have high facial eczema risk from Jan-Apr in regions where warm, humid conditions result in rapid increases in spore numbers. Heavy grazing to low residual yields can exacerbate the scale of the disease and severely affected animals can die within 3-4 weeks. There is no treatment for animals which suffer severe liver damage from the toxins released. Symptoms may be clinical (visual symptoms observed) or sub-clinical (no visual symptoms) so if animals show clinical signs all stock should be removed from the pasture and moved to a ‘safe’ pasture with adequate shade provided. Production levels of affected livestock may be reduced for the rest of their productive lives if not removed immediately. When ingested by grazing animals spores release a toxin (sporidesmin) which damages bile ducts and the liver and stock become photosensitive. In severe cases animals die.

Although the fungus is found in grazed pastures worldwide the most severe problems occur in New Zealand. Exposed skin of infected animals develop weeping dermatitis and scabby skin and these areas can become infected or fly-blown. Furthermore, infected animals can have reduced fertility levels and reduced immunity levels to other diseases. A range of fungicide sprays can be applied to pastures but for control they must be applied before spore numbers increase. When spore numbers reach >200 000/g fungicides are unable to reduce them to safe levels so the risk of infection remains high.

Breeding programs which use disease resistant genetics is a major management tool to reduce prevalence of this disease. Use of rams tolerant to FE will not result in 100% of progeny showing tolerance but fewer progeny will be susceptible which will reduce incidence within the flock. Rams are tested using the Ramguard FE tolerance testing Service. Other management tools to control the disease infected animals include treatment with zinc salts which can help protect susceptible animals as the zinc binds with the toxin which can then not damage the liver or bile ducts. Controlled release zinc treatments are more expensive but offer protection for up to six weeks compared with drenches which do not offer protection for as long. Zinc can also be applied to pasture prior to grazing. Alternative pastures which have high legume content, tall fescue and/or chicory are recommended for grazing during periods of high risk. Forage crops are also a safe option. Spore levels are highest in regrowth from urine patches (more litter and a higher N content).

Johnes disease
Johnes Disease is a chronic disease caused by Mycobacterium paratuberculosis which affects the intestines of grazing ruminants. The disease causes wasting, loss of condition, diarrhoea and thickening of the small intestine. There is no treatment but a vaccine is available. The disease appears to be contracted while stock are young and incubates for 18 months before symptoms appear. Diagnosis is by faecal examination or blood test, but there is no reliable test available. Consequently this disease and its prevention are very difficult. Infected stock should be removed and culled immediately to prevent distress to the animal as the disease develops. Furthermore, the disease can be passed to foetuses and suckling young. Pastures may remain infective for up to 12 months but this is less than the time the disease incubates prior to symptoms being observed.

Footrot
This is an infectious bacterial infection of the hoof caused by Dichelobacter nodosus but Fusobacterium necrophorum bacteria must also be present. Prevalence increases in warm, wet and humid conditions. High stocking rates facilitate the spread so it is important to ensure unaffected stock are prevented from accessing areas where infected stock have been within the previous 10 days. Hooves of infected animals can be pared to increase airflow and footbaths containing formalin or zinc sulphate are used. Culling of susceptible stock is a viable option as it also reduces genetic predisposition to footrot which may carry through progeny. Increasing genetic tolerance in stock is a major breeding objective. Rams can be tested for tolerance with the Lincoln University Footrot Gene-marker test.

Scabby mouth
A viral infection which infects sheep through breaks in the skin. Scabs mainly form on the lips, nostrils and face. Production declines because of reduced feed intake but the disease usually clears within 2-4 weeks. Vaccines are only used on properties where the disease is present as the virus can last for long periods on the ground. Carrier sheep facilitate spread of the disease within flocks. Antibiotics can be administered when secondary infection occurs.

Liver fluke
This disease can cause severe liver damage but infection is limited to damp areas where Lymnaea columella snails are found which allow completion of the fluke’s life cycle. Flukicides are available to treat infected livestock but reducing snail numbers or preventing grazing in wet areas are alternative management strategies to reduce disease incidence.

Dairy herd diseases
Herd testing is used to identify the best genetics for production and to monitor dairy animals for diseases which include Enzootic Bovine Leucosis (EBL). This is a viral disease which affects the immune system and can cause fatal cancer. Tuberculosis (Tb) can also be fatal and may infect humans. Milk companies impose demerit points for a range of required milk quality tests if standards are not met.

Two herds tested positive for EBL in the 2007/08 season and were culled while another two herds were treated (DairyNZ and LIC, 2009). Incidence of EBL is considered low by international standards. Nationally, herd incidence of EBL was <0.17% and no detections occurred in the North Island. For Tb testing, the prevalence of host species which include possums and ferrets determines the vector status of an area. Legally, all movement of cattle must be documented in case of an outbreak. Almost 3.1 M dairy cows were tested in 2007/08 of which 402 tested positive. Most animals (299) were identified in the South Island and 82% of these were found in areas with a known risk. The industry as a whole is proactive in monitoring, treating and preventing the infection and spread of disease.

 

 

Socio-economic limitations of pastoral agriculture
The New Zealand economy has relied on pastoral production for over 150 years. Initially wool, skins and tallow were exported but with the introduction of refrigerated shipping meat and dairy products have been major exports since the late 19th Century. Consequently government policy has normally been favourable to pastoral farmers.

Currently legislation to control pastoral use of land relates to limitations being applied to some high altitude (above 900 m) tussock grasslands and to the extremely erosion prone soils in some steep hill country where tree planting is encouraged.

Land tenure of pastoral farms is mainly freehold. There are however some large areas of Maori land in the North Island which are farmed successfully as incorporations on behalf of iwi (tribal groups). Much of the South Island high country is Crown (Government) owned land which is leased for grazing to individual pastoralists. Some of those leases are currently being renegotiated. There are no communal pastures as flocks or herds are owned by individual farmers or commercial companies. These privately owned livestock do not graze any pasture or natural rangeland in common with domesticated livestock owned by other farmers.

The land tenure systems and lack of communal grazing mean that the New Zealand pastoral landscape is characterised by post and wire fences to maintain individual farm boundaries to avoid mixing privately owned livestock. Subdivision fences within farms form separate paddocks (grazed fields) so that different classes of livestock (species, age, sex) on a farm may be grazed separately. This provides a high degree of farmer control on when and where animals graze. The specific grazing management requirements of pasture species (e.g. lucerne) are more easily achieved with this acceptance of the need for fenced paddocks.

Because most products from pastoral production are exported, market access is an issue of national importance. New Zealand strongly advocates international free trade and the removal of agricultural subsidies in developed countries. The New Zealand government does not subsidise farm production. This ensures that scarce resources of land, capital and labour are used efficiently. This has led to New Zealand pastoral products being able to compete on world markets. However, the profitability of the New Zealand pastoral exports is vulnerable to exchange rate fluctuations and the use of rural subsidies by its trading partners.

More recently (2008/09) the extreme distance of New Zealand from its main markets has resulted in its pastoral products being challenged on the basis of their total energy content when delivered to northern hemisphere consumers. The suggestion that the concept of food miles should disqualify New Zealand pastoral products in environmentally sensitive western markets was shown to be false when the energy cost of livestock production in New Zealand plus its transportation was compared with competing subsidised UK and European local meat and dairy products (Saunders et al., 2006). New Zealand lamb was produced four times more efficiently and milk solids production efficiency was double compared with UK lamb and milk solids production. The greater use of N fertilizers, grain feeding and the need to house animals in winter in northern hemisphere production systems results in higher energy costs of production than the imported New Zealand livestock products. The low energy cost of production of the NZ products are related to the high reliance on N fixation by pasture legumes, relatively low use of N fertilizers, little grain feeding and the fact that grazing livestock are outside all year without winter housing. These production efficiencies allow New Zealand pastoral products to have lower total energy cost even when the cost of delivery to export markets is included.

New Zealand has a declining area in pastoral production. With marginal land being excluded from grazing and the encroachment of urban development the only way to increase pastoral production will be through intensification.

Crown pastoral land act 1998
About 10% of the land area of New Zealand, the remnants of which are predominantly in the South Island High Country, is government owned and leased to farmers for grazing. These leaseholds have tenure in perpetuity and are renewed every 33 yrs. During the tenure review process, which is initiated by the farmer or occurs when a Crown leased property is sold, the land resource is evaluated and some land may be sold to the Crown. The farmer may then have the opportunity to purchase back, as freehold, the more productive lower altitude land. The high altitude land which is valued for recreation and conservation may be retired (Swaffield and Hughey, 2001) and taken over for management purposes by the Department of Conservation. The ability of the farmer to freehold land means the restrictions set on land use which were part of the leasehold tenure are voided. Tenure review is a contentious process as it affects the farmer’s ability to manage their land and public access, nature conservation, wildlife, anglers and game hunting groups.

The resource management act (RMA) 1991
In the mid 1980s government agencies were reformed and this was followed by a major revision of legislation and local government (Ministry for the Environment, 2006). The RMA was the first policy of its type in the world and replaced almost 60 previous resource and planning statutes. The RMA is concerned with the environmental impacts of human activities on land, air, water, coastal, geothermal resources and pollution management. Specifically, it manages the environment while encouraging social, economic and cultural well-being of the people and communities within that environment.

The Act is intended to provide sustainable management plans which will protect the environment for future generations. The RMA states that every New Zealander, resource user and developer has obligations/responsibility to prevent, remedy or mitigate the effects of their actions on the environment.

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