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On-site research for the estimation of the nutritional status of sheep and goats grazing at El-Omayed pasture area

M.A. Naga and H. Abd El-Salam
Faculty of Agriculture, University of Alexandria
Alexandria, Egypt


Summary
Introduction
Materials and methods
Results
Discussion
References


Summary

A governmental resolution which allowed the Bedouins of the Matrouh Governorate to export sheep and goats resulted in significant movement of flocks from the Nile delta to the Marsa Matrouh area. The number of heads of small ruminants moving to the new area was almost double that of the normal and led to overgrazing and a deterioration of many parts of pasture land.

Research was initiated to determine the present nutritional status of sheep and goats at El-Omayed, 90 km west of Alexandria. Two university of Alexandria employees introduced the research team to Bedouins at the site. Experiments to determine forage preference, feed intake, grazing periods, the nutritive value of consumed material the present and the proper carrying capacity were all conducted using flocks of one influential Bedouin. His flocks were managed by his five sons.

The grazing period and DM intake of goats in summer were between 1/3 to 1/2 their corresponding values in winter. Sheep did not show such degree of difference between summer and winter. The studied pasture area was capable of supplying the existing sheep with 77 and 85% of their TDN requirements in summer and winter. The corresponding values for goats were 37 and 100%, respectively. The proper carrying capacity of the studied area was about 5 feddan/head in summer and 2.5 feddan/head in winter.

1 One feddan = 0.42 ha

Treatments for improving the nutritional status of animals were suggested. A mineral mixture was formulated to compensate for the recognised local mineral deficiencies. It was manufactured in the form of licking blocks. This supplement improved the performance of animals during summer by 22%. The first co-operating Bedouin helped in extending the distribution of these blocks to neighbours. Two years later, the number of clients using the blocks reached 14.

Introduction

The pasture area at the northern coastal zone of the western desert of Egypt (administratively known as Governorate of Matrouh) was lately overgrazed due to the doubling of sheep and goats there, during the last 10-12 years. This was a result of the Government's action allowing the Governorate of Matrouh to export sheep and goats. Export price was higher than the local market price. However, during this period, feeds became scarce and the Bedouins of Matrouh had to import feeds from the Nile delta where feeds were also in short supply.

The present study aimed at studying the nutritional status of the animals in El-Omayed (90 km west Alexandria) as a sample area of the Matrouh Governorate. Means of improving the present situation were also investigated. The implications of such a study in a desert environment are described with emphasis on the social and economical value of the results.

Materials and methods


Identification of co-operating Bedouins


El-Omayed has a temperature range of between 10 - 20°C during the winter and 30 - 40°C in summer. Rainfall averages 150 mm annually, two thirds of which falls between November and February. Rainfall is more intensive along the coastal region, diminishing rapidly inland. Sandstorms occur during the spring, frequently lasting three days over a 50-day period, called El-Khamasin. Relative humidity during the summer may reach 72% decreasing to 16% in the winter.

The soil at the experimental site is calcareous alluvium with a high content of limestone (30-35% CaCo3). The soil texture is fine and it is moderately affected by salts. However, it is very poor in contents of organic matter, phosphorus, nitrogen and most microelements.

The animals at the experimental site were mainly sheep and goats (dark coloured) with very few donkeys. Animals under the site conditions have one breeding season per year. Sheep at the site were of the Barki breed. They were white coloured with black head. Flock size ranged between 40 and 200 heads per person. In 1965 sheep exceeded goats by 2.7:1. This number now is moving towards a lower sheep/goat ratio. Veterinary service was almost negligible in the area. Mortality rate, especially around the age of weaning, was quite high (25-50%) with a peak in summer.

The recognised (prevailing) plants on site were Cutandia dichotoma, Asphodelus microcarpus, Thymelaea hirsute, Plantago albicans, Helianthemum lippii, Canducellus spp, Convolvulus lanatus and Rumex spp.

Identification of co-operating Bedouins

The research group was introduced to the inhabitants of the experimental area through two University workers who are from this area and are well-known by the Bedouins there. Both individuals had maintained close contact over the years with their friends and relatives at the research site. They also observed the social traditions of the district and were therefore viewed as solid personalities. They did not exhibit the paternalistic behaviour characteristic of many non-Bedouins. These University employees also knew and understood the research staff and the purposes of research in question. They were pleased to demonstrate to their employers their influence in the district. Through them, the Sheikh, his five sons and thereafter, 12 other Bedouins at the site were convinced to cooperate with the research team. This approach was required since it is obligatory in Bedouin society to move under the umbrella of the most influential person on site.

The Bedouin participation consisted of providing the animals for the research team to carry out its observations and tests. Their involvement was obtained under the following conditions:

a) A basal payment of 100 EGP*/month to the head of the family. In addition, frequent gifts (mainly of sugar, tea, flour and clothes) were made, depending on the occasion.

b) A rental fee of one EGP/head/month for each animal studied.

c) A salary (30 EGP/month) for the person (one of the Sheikh's sons) who shepherded the experimental flock.

d) At the beginning of each experiment, the head of the family received between 15 and 30 EGP depending on the type of experiment.

e) Salaries were provided for assistants as needed. These assistants were always women or girls since the boys did not agree to work. Each young girl employed for collecting range plants was paid 0.35 EGP per 25 kg bag filled with a certain plant species. The 12 to 16-year-old girls who assisted in the experiments such as digestibility trials received 20 EGP/week.

f) Any veterinary care was preceeded by some payment to the head of the family in addition to those who actually assist in adminishing the treatments.

* EGP = 1 Egyptian pound = 0.45 US$

Experimental design; The oesophagally-fistulated sheep and goats (as described by Schutte et al. 1971) were hired from the Sheikh. Three sheep and two goats were selected. surgery was made at the experimental station of the Faculty of Agriculture, University of Alexandria. After recovery, the animals were returned to the site to be used in determining grazing preference and feed intake.

The actual grazing period was determined by observation using four research assistants who followed grazing animals (one observer per animal) measuring the grazing time with a stop watch. Sixteen sheep and sixteen goats were observed on four consecutive days each month over the whole year.

Digestibility and mineral balance trials were conducted on three sheep and three goats during both the winter and summer seasons. These experiments were conducted according to conventional methodologies.

The forage production of each feddan of rangeland was estimated by using randomly - selected quadrat measurements from 10 locations per feddan. For each quadrat, the consumable plant parts were collected manually, weighed, and the dry matter content was estimated. These measurements were made monthly over a complete year.

The number of feddans required to feed an animal was then calculated by using standard feed requirement data and measuring feed availability at the experimental site.

Studies on the effect of feed supplements were conducted on two separate flocks of the Sheikh, each of 48 heads of sheep and goats. The supplements were combined in a block manufactured at the University laboratory. The carrier material was ground maize stalks bound by molasses. The additives (minerals and vitamin A) were dissolved in the molasses. Performance of the treatment was measured indirectly by the willingness of the Bedouin to continue using the blocks in subsequent years.

Logistics of field research: The experimental programme in El-Omayed lasted for two consecutive years (two winter and two summer seasons). A research assistant (Ph.D. student) with four technicians visited the site twice weekly. They used a Jeep for transport from the faculty location to the experimental site, a distance of about 180 km round-trip. Transport costs were about 0.10 EGP per km. Two weighing balances were left on site, one for the animals and the other for preparation of rations for the digestibility trials. Bags, rubber funnels and tubing with harnesses were required for the digestibility and balance trials to collect the faeces and urine. A specific building for housing the fistulated and experimental animals was constructed on-site.

The costs of such facilities were as follows:


USD

1. Vehicle

9,000

2. Bags, funnels and harnesses

800

3. Oesophagal fistula (3 pieces)

300

4. On-site building

200

5. Chemicals and glassware

1,000

6. Weighing balances

700

Results

Consumed feed by eosophagally-fistulated animals would either drop through the fistula into the fitted bag, or it passed directly to the rumen. The amount of consumed dry matter (DM) which dropped into the fistula was found to be higher in goats than sheep as indicated in Table 1. The actual DM consumption of feed during a 30-minute period can then calculated as follows:

Botanical analysis of the material collected from the fistula (Table 2) indicated that species preference was similar for sheep and goats in summer. During the winter, sheep grazed more Asphodelus microcarpus and less Thymelaea hirsuta, than goats.

Table 1. Distribution of consumed DM (g/33 min.) between the fistula and the rumen.

Type of animal

Season

Consumed

Dropped in the fistula

Passed to the rumen



g

%

g

%

g

%

Sheep

Summer

160

100

60

38

100

62


Winter

66

100

16

24

50

76

Goats

Summer

55

100

26

48

29

52


Winter

56

100

21

37

35

63

Table 2. The percentage distribution of consumed pasture plants by sheep and goats during the summer and winter seasons.


Sheep

Goats

Plant species

Summer

Winter

Summer

Winter

Asphodelus microcarpus

85

85

85

70

Thymelaea hirsuta

6

10

6

25

Rumex spp.

-

1

-

1

Canducellus spp

-

1

-

1

Helianthemum lippii

4

1

4

1

Plantago albicans

4

1

4

1

Cutandia dichotoma

-

1

-

1

Convolvulus lanatus

1

-

1

-

Table 3 indicates that the daily DM consumption by sheep and goats was almost similar in the winter while during the summer, goats had a much smaller intake of DM. On an energy intake basis (Table 4) goats suffered more than sheep in the summer season, obtaining only 36.7% of their required total digestible nutrient (TDN). This suggests the importance of giving goats priority in the use of government-distributed concentrates. In addition, providing goats with some overhead shelter during the summer season would be desirable.

The results in Table 4 indicated that the pasture conditions in winter would enable a carrying capacity of one small ruminant per 2.5 feddans (Table 5). It may be assumed that the yield of feed per feddan during the summer was actually the residual of the pasture, that was not consumed during the winter season. In summer season the carrying capacity must be at least 5 feddans per animal if they were to obtain all their requirements from the pasture alone.

Table 3. DM consumption, digestible protein and TDN content of summer and winter pasture diets grazed by sheep and goats.


Sheep

Goats

Season

Grazing period

Consumed DM period

Grazing

Consumed


(h/day)

(g/hd/day)

(h/day)

(g/hd/day)




%

%



%

%



DM

DP

TDN


DM

DP

TDN

Summer

3.25

1264

4.6

59

2.5

550

4.5

63

Winter

4.25

1338

2.3

73

5.0

1529

2.1

66

Table 4. Ability of local pastures to meet TDN requirements of grazing sheep and goats at the El-Omayed site during the summer and winter seasons.

Season

TDN % in consumed DM

Consumed TDN (kg/head/day)

Required TDN (kg/head/day)

TDN intake as percentage of requirements


Sheep

Goats

Sheet

Goats

Sheep

Goats

Sheep

Goats

Winter

70

68

0.936

1.040

1.1

1.0

85.1

100

Summer

61

60

0.771

0.330

1.0

0.9

77.1

36.7

* sheep body weight of 45 kg and goats of 40 kg.

Table 5. The carrying capacity (fed/animal) of grazing land at the El-Omayed site for sheep and goats.


Available feed

TDN requirement

Carrying capacity

Season

kg DM/feddan

kg TDN/feddan

Sheep

Goats

Sheep

Goats

Summer (6 months)

70

42

201

191

4.8

4.7

Winter (6 months)

118

82

201

191

2.5

2.4

The patterns of mineral balances indicated (Table 6) positive balances in sheep and goats during the winter season. Some problems (specially in sheep) of mineral deficiencies were identified in the summer season (if the animals were not supplemented with concentrates). Calcium balance was unusually high especially with sheep. When a mineral mixture was composed (Table 7) and given to the animals to compensate for the level of deficiency, the TDN content of the same amount of consumed DM was increased by 22% (Table 8). Feed intake increased by an average of 18%. These results indicated that providing grazing animals during the summer season with some licking blocks containing the deficient minerals could raise the adequacy of their TDN intake (given the present levels of DM intake) to 98 and 50% instead of 77% and 37% of their requirement (see Table 4) for sheep and goats, respectively.

Table 6. Mineral balance patterns (g/head/day) of sheep and goats grazing the El-Omayed site in the summer and winter seasons.


Sheep


Coats


Mineral

Summer

Winter

Summer

Winter

N

1.55

4.60

1.05

0.70

Cu

0.01

0.03

-0.05

0.00

Fe

-0.08

0.44

0.47

0.65

Zn

0.08

0.03

0.08

0.03

Mn

-0.01

0.04

0.03

0.01

Ca

7.01

28.56

6.18

0.74

Mg

1.52

0.40

1.73

0.08

S

-2.91

0.20

1.42

1.90

P

-0.02

0.80

-0.48

0.13

Na

10.76

1.07

13.19

1.73

K

0.69

1.15

12.07

1.91

Table 7. Composition of the supplemental mineral mixture for grazing sheep and goats in the summer season.

Mineral salt

G/Head/day

Sulfur

3.368

Ammonium phosphate

1.104

Zinc sulphate

0.092

Ferric sulphate

0.340

Manganese oxide

0.032

Total

4.936

Table 8. Effect of the mineral supplement on the digestibility of nutrients for sheep fed summer pasture plants


Coefficient of digestibility (%)

Item

Without supplement

With supplement

DM

66

80

CP

44

52

EE

65

73

CF

85

89

N-Fext

70

86

TDN

62

73

DP

2.86

2.63

Discussion

The preference of Asphodelus microcarpus and Thymelaea hirsuta, although both contain colchicine and caumarine (Tockholm et al, 1956), is not explainable within the limits of the present work. However, it may be speculated from the chemical composition of the individual plant species that these two selected plants had less content and relatively more balanced calcium/phosphorus ratios. The ash content of these two plants averaged 10% while it was 15 - 22% in other plants.

The animals were selecting the more digestible fractions of the plant. This would explain the high TDN content of consumed DM (see Table 3) in both winter and summer.

The failure of goats to manage enough feed intake during summer (Table 4) as compared to sheep may be explained on the basis of body colour. Goats were either black or dark brown which may have resulted in higher heat stress. Sheep were of a white body colour.

The yield in kilogram of consumable feed per feddan is mainly dependent on rainfall rate as claimed by Field (1980). The same author indicated that soil fertility and rate of water evaporation from the plants are also contributing factors to pasture yield. Field (1980) found that DM yield at pasture increases threefold by rainfall increase of 60%. Accordingly, the carrying capacity presently found (Table 5) should not be taken as a fixed estimate. Every year such a parameter should be revised and adjusted. The mineral mixture supplement (Table 7) should be also formulated according to the deficiencies found in each location. Results of Yassen (1958) and Van Eys (personal communication) emphasise the significant role minerals play on feed intake and animal performance. Naga (1984) indicated that a combination of vitamin A, urea and minerals significantly improved the performance of adult and growing animals. The excessive Ca retention (Table 6) could be adjusted to normal by feeding a calculated amount of wheat bran (Naga, 1987). Phytic acid in the bran would chellate the extra Ca in the diet and then prevent its absorption.

The above information was used for manufacturing licking blocks in the Faculty's laboratory. The licking blocks contained mineral mixture, urea, Vitamin A, wheat bran, sodium chloride, molasses and cement. The blocks were used for the Sheikh's flocks only. The shepherds observed the crowding of animals around the blocks in summer, the fast drop of placenta after the dam's delivery (2hrs instead of 2-3 days), and the significant reduction in offspring mortality. The research team was asked to provide some licking blocks without mentioning that the blocks would be passed onto neighbours. The licking blocks were given free at the beginning, and later at a cost when neighbours expressed more interest. The number of clients which started with four, gradually reached 14 in 1.5 years. The positive side in this activity is the continuity of purchasing the blocks although the research team left the site when the clients were 11.

References

Field, D.I. 1980. Grazing capacity of rangelands. Somali Range Bulletin No. 10 Nov. 1980. p 6.

Naga, M.A. 1984. In Better utilisation of crop residues and by-products in animal feeding: Research guidelines-state of knowledge. FAO Publication No. 50. FAO, Rome.

Naga, M.A. 1987. In: Isotope-aided studies on livestock productivity in Mediterranean and North Africa, countries. IAEA (International Atomic Energy Agency), Publication. Vienna. Austria.

Schutte, J.A., Wilke, P.I. and Compaan, J.P. 1971. Surgical procedure for the creation of an oesophageal fistula in sheep. J. Agronmalia 3:99.

Tockholm, V., Drar, M. and Abdel Fadeel. 1956. Student's Flora of Egypt. Anglo-Egyptian Bookshop, Cairo.

Yassen, A.M. 1958. M.Sc. thesis. Univ. of Alexandria, Alexandria, Egypt.


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