11.0 PASTURES FOR DAIRY PRODUCTION
The amount of milk a cow can produce is directly related to the quality and quantity of food which she eats. If quality and or quantity is lacking the cow will respond by producing less milk. In the short term (say less than one week) the cow may mobilise her own body reserves in order to maintain her production of milk. If she is not fed sufficiently over a longer period both daily production and the length of lactation will be reduced, Also the cow will be in a poor (thin) physical state, the likely consequence of this is an extended post-partum anoestrus (the length of time often calving before a cow is able to get in calf). Therefore the cow will have an extended calving interval - it will be a long time until she has her next calf
Income per lactation includes one calf valued at $500.00
[Allowance of $800.00 has been made for the sale of the cow at the end of her productive life
The cows both calve for the first time at two years of age and leave the herd (sold) at seven
years old Input costs have not been included, it is likely that costs will be slightly higher for the well fed cow although many costs will be the same. All other factors, such as breeding, are held constant]
From this it can be seen that it is very much in the farmers interest to ensure that the cow is well fed and cared for. Sample comparisons including costs and benefits for different situations are included later in this publication.
11.1 Areas Suited to Dairy Production
It is possible to farm dairy cattle in any area where beef can be produced, however high, wet less fertile land should be avoided as should be dry and infertile or very rocky land as the greater levels of supplementary feeding needed to maintain production will have a negative effect on profit. Low altitude moderate to low density coconut plantations (less than 125 20 year old palms per hectare) are ideal for smallholder dairying.
11.2 Choice of Pasture Varieties
Whilst a cut and carry system is possible, most farmers will find that provided they have enough land, a grazing system be it tethered or within a fence is more productive (reef Reynolds S G a 1995). It is most important that dairy cattle be offered well managed pastures consisting of grass and legumes.
As an example, for smallholder dairying in Samoa the most appropriate grass species for most locations and levels of management is batiki grass;Achaemum uristatium, there are however some useful alternatives which are described briefly below. It is widely agreed that in selecting the most appropriate pasture variety for improved production, the important factors to consider are.
Below is an introductory description of some pasture varieties Which are currently used in the
South Pacific for dairy production.
For more information on the characteristics, establishment and management of pasture varieties
consult your local livestock extensionist or pastures advisor.
Batiki grass(Ischaemum aristatum)- see Photo 1.
is easy to establish and grows well in high rainfall areas, it has low drought tolerance. Grows well in moderate shade such as under coconuts. Under good management fair to good animal performance can be obtained, 400 kg beef per hectare/year has been produced in Samoa using a short length rotational grazing regime to maintain pasture quality. Is very competitive -controls weeds well. Usually grown from cuttings.
Signal grass(Brachiaria brizantha)- see Photo 2.
grows well in most places that batiki will grow except the higher, wetter and less fertile lands, it is more tolerant of dry conditions than batiki. Signal is slightly less tolerant of shade than
batiki. Given good management signal pastures will produce more milk and or meat than batiki. May be grown from cuttings.
Splenda setaria(Setaria sphacelata var. splenda) see Photo 3.
is a newly introduced grass which has shown very good potential for dairy production. Reports from Vanuatu and Fiji indicate that splenda gives the highest milk production of any grazing system. Also the author has seen splenda completely suppressing navua sedge (Kyllinga polyphylla) in Fiji, the ability of a pasture plant to compete successfully against weeds is a great advantage. Farmers in all but the drought prone areas, and with good levels of management, who do not have an established improved grass species should consider planting this variety. May be grown from cuttings, or seed.
Guinea grass(Panicum maximum)
An erect tussock grass which can spread by rhizomes at the base.
Very widely used forage in the Pacific, often growing voluntarily on roadsides and fallow cropping land. Suitable for grazing and cut and carry. Young guinea foliage has a high level of digestibility [in-vitro digestibility of 68%, 58%, 54% and 50% have been measured in regrowth of 2, 4,6 and 8 weeks], so is well suited to dairy production, However it does require careful management, particularly during dry periods because its tussock like growth habit is susceptible to overgrazing resuking in weed invasion starting on the bare ground surrounding the plant base.
Can be planted by seed or rooted splits.
Para grass (Brachiaria mutica)
A robust creeping perennial which tends to spread by rooting at the nodes. Stems and leaves are very hairy. The infiorescence is a panicle with up to 20 densely seeded racernes.
Widely grazed in the Pacific particularly well suited to wet climates and swampy areas [it can grow in water]. Does not have good dry area performance. Para is reputed to have higher digestibility than its relative signal grass [B decumbetis], but tends to be more difficult to manage as it does not creep as well as signal and is therefore more susceptible to weed invasion.
Can be planted by seed or lower stem cuttings [which have primordial roots]
Elephant or napier grass(Penisetum purpureum)
A very tall [upto 7m] deep rooting, erect grass with short rhizomes. The plant is bristly with tough cutty leaves. The inflorescence is a spike like panicle, very little viable seed is formed.
Widely grazed in the Pacific particularly by tethered cattle in non-fenced areas. Has great potential for dairy production as a cut and carry variety, especially the hybrid types which have higher production and digestibility than common types. Potential production is the highest of all grasses, figures of 60 000 kg DM/ha per year have been achieved with intensive management and fertiliser use. Has very good drought tolerance. Planted by stem cuttings with 3 nodes.
11.3 Grasses for Drought Prone Areas
Farmers should consider whether or not the locality in which their farms lie are prone to drought. This is characterised by extended periods without rain which cause plant growth to suffer e.g. wilting, low plant growth rates or plant death. In these cases pasture varieties (grass and legume) which are able to survive and or possibly maintain production in dry periods should be selected.
If you are in a drought prone area, you should plant at least some of your pasture area in drought tolerant varieties
Koronivia grass(Brachiaria humidicola).
has better drought tolerance than signal, which it is similar in appearance to but less hairy and tougher foliage with a less erect growth habit.
This grass grows well under moderately shaded conditions i.e. more than 70% light (ref Reynolds S G b 1988) and has good drought tolerance. May be grown from cuttings
Bisset creeping blue grass(Bothriochloa insculpta cv Bisset.)
is newly introduced to Western Samoa and shows considerable promise as a high yielding drought tolerant forage, is similar but so far appears higher producing than hatch grass(Bothriochloa insculpta cv hatch). May be grown from cuttings.
The jointvetch(Aeschynomene americana cv Glenn, and Aeschynomene americana cv Lee)- see Photo 4.
Glenn is an annual to weak perennial sub-shrub which has proven itself to be a highly productive as well as easily established and managed pasture legume in South Pacific grazing systems.
Lee is a more recently introduced variety which has shown Glenn's strong adaptation to local conditions, in addition; being a perennial Lee does not have to regenerate itself each year by seeding. Consequently, being a lighter seed producer, Lee tends to produce leaf all year rotund whereas Glenn dies off in the dry season. Both jointvetches should be included in dairy pastures. Glenn jointvetch has proven itself to be adapted to a very wide range of soil and rainfall environments, both shaded and unshaded. These forages can combine well with grasses such as batiki and signal. Grown from seed.
Greenleaf desmodium (Desmodium intortum)
This is a deep rooted trailing perennial which has been proven (in Samoa) to grow well in all areas except drought prone zones and areas of very low fertility. Sometimes slow to establish, probably due to its small seed size, greenleaf persists well under rotational grazing systems and has been shown to be one of the best pasture legumes in coconut plantations. It is very tolerant of wet conditions. Grown from seed.
Centro (Centrosema pubescens) see Photo 5.
A perennial creeping plant which is vigorous and capable of persisting in grass dominated pastures. Often seeds can be picked from plants found growing on fences. Drought and moderately shade tolerant. Grown from seed.
Hetero (Desmodium heterophylium)
A low growing perennial creeper with small ovate trifoliate leaves and pink flowers. This
extremely adaptable legtime is widely occurring in Samoa and other countries. Hetero is planted as a cutting, planting material is often available on the road sides. It may be planted into dungpats in existing pastures or mixed with grass cuttings in new plantings. It grows well under coconuts and mixes well with improved grasses.
Siratro (Niacroptihum afropurpureum)- see Photo 6.
now found in many Pacific island countries. This twining perennial is deep rooted, quite easy to establish, combines well with grasses and will grow in a variety of soil types but not heavy clays. Has quite good drought tolerance but does not tolerate very wet conditions, as all the foliage will collapse very quickly with fungal leaf rot[Rhizoctonia solani]. Established from seed does not generally require rhizobial inoculation.
Stylos (Stylosanthes species)- see Photo 7.
below are notes on 2 stylos which have been grown with success in the Pacific:
I. seca stylo
2. verano stylo(Stylasanthes hamata) this is a low growing short lived perennial with many branches. Leaves are trifoliate with narrow pointed leaflets which are bright green and silvery on the underside. Has similar drought tolerance and growing requirements as seca.
Pinto peanut (Arachis pintoi)- see Photo 8.
a very strongly creeping stoloniferous perennial which roots at the nodes. Not yet widely grown throughout the Pacific but has a lot of potential due to shade tolerance and ability to combine well with grasses and tolerate heavy grazing. Foliage has very good digestibility
Some problems have been encountered with establishment due to poor seed quality and moculation. Recommended to first establish a small nursery and to transplant rooted stolons.
Glycine (Neonotonia wightii)
A perennial twining herb with a woody crown and pinnately trifoliate leaves bow on slender stems. The deep tap root gives good drought resistance. Best suited to areas with rainfall of 1000 to 2000 mm., does best on well drained soils. Varieties Tinaroo and Cooper prefer better soils whilst var. Malawi will tolerate acid and low fertility soils.
Glycine is very strongly growing and combines well with tall grasses, will smother weeds and fences if ungrazed.
Planted by seed treated with cow pea strain moculant.
Sensitive plant (Mimosa pudica)- see Photo 9.
This low branching, creeping, thomy perennial is widespread. Sometimes considered a weed, sensitive has a useful role as a pasture legume providing it does not dominate a pasture due to overgrazing. It is widely adapted to a range of conditions including under coconuts. Tolerates very heavy grazing. Not recommended for planting.
11.5 Shrub Legumes
Shrub legumes have great promise in improving the quality of diet for dairy cattle. The ability to produce large amounts of digestible, high protein feed at low cost makes them an important component of the dairy feeding programme. Shrub legumes may be grazed in-situ; planted in rows (plant density of 2 000-4 000 plants per hectare) or in a high density feed bank (approx. 10 000 plants per hectare, or 2 000 6 000 pants/ha plus elephant grass). Many shrub legumes are well suited to cut and carry, this includes locally occurring varieties such asAlbizia chinensis.
Calliandra (Calliandra calothyrsus) see Photo 10.
A high yielding shrub legume capable of growing to around 7 metres. This tree legume has been shown to persist well in rotationally grazed pastures, provided that it is cut to about 1 metre after grazing. Plant persistence can be adversely affected by damage by stock especially when grazed by large and boisterous animal such as bulls. Well suited to cut and carry systems. The foliage has quite high tannin levels, therefore cattle need to be "forced" [given no choice of feed] to eat it initially however after the first grazing, they will eat it happily. Calliandra is tolerant of high rainfall (5000 mm pa) and low fertility but is not drought tolerant. Usually planted as seedlings.
Leucaena (Leucaena leucocephala)- see Photo 11.
There are two varieties of this shrub legume species proven for Western Samoan pastures:
Cunningham leucaena and leucaena K636.
Whilst these varieties are considerably lower yielding than Calliandra, they are extremely persistent once established and offer higher quality forage. Leucaenas are proven to grow in rainfalls of around 3500 mm pa, however they probably have their strongest role to play in the drought prone areas due to their ability to thrive in dry conditions. Leucaena leucocephala can be heavily damaged by insect [psyllid] attack, leucaena hybrids such as KX2 have been developed which have a greater resistance to psyllids and are potentially higher producing. KX2 and KX3 are currently being evaluated in Samoa . Usually planted as seedlings which have been raised in a nursery.