S.M. DasLivestock Production Research Institute
Private Bag
Mpwapwa
Tanzania
Summary
Resume
Introduction
Materials and methods
Results
Discussion
Conclusions
Acknowledgements
References
A 1 yr study to evaluate blended dairy goats was conducted in the semi-arid areas of Tanzania at Kongwa and Malya stations. For 83 blended does bred at Kongwa apparent fertility was 59.0%, fecundity 83.1% and prolificacy 140.8%: these figures were 68.3%, 89.9% and 131.6% for 139 does at Malya. Breeding weights were 29.4 ± 0.96 kg at Kongwa and 32.1 ± 0.55 kg at Malya. Birth weights were 2.53 ± 0.07 kg at Kongwa and 2.44 ± 0.04 kg at Malya and weaning weights 8.7 ± 0.29 kg and 10.0 ± 0.18 kg at the 2 stations. Birth type and sex influenced weaning weight (P < 0.01) at both sites. Lactation yield at Kongwa was 120.3 ± 8.72 kg and lactation length 266.0 ± 2.66 d, butter fat content being 2.7%. Age at kidding and birth type did not influence lactation yield.
L'étude de la productivité d'une race laitière caprine synthétique s'est déroulée pendant 1 an sur les stations de Kongwa et de Malya dans la zone semi-aride tanzanienne. Pour les 83 chèvres élevées à Kongwa, la fertilité apparente était de 59,0 p.cent, la fécondité de 83,1 p.cent et la prolificité de 140,8 p.cent. A la station de Malya ces paramètres étaient respectivement 68,3 p.cent, 89,9 p.cent et 131,6 p.cent (n = 139). Le poids des reproductrices étaient de 29,4 ± 0,96 kg à Kongwa et de 31,2 ± 0,55 kg à Malya. Les poids à la naissance étaient de 2,53 ± 0,07 kg et de 2,44 ± 0,04 kg à Kongwa et à Malya tandis que les poids au sevrage atteignaient 8,7 ± 0,29 kg et 10,0 ± 0,18 kg. Le type de naissance et le sexe influencent significativement le poids au sevrage (P < 0,01). La production laitière à Kongwa atteignit 120,3 ± 8,72 kg en 266,0 ± 2,66 j avec un taux de matière grasse de 2,71 p.cent. L'âge à la mise bas et le type de naissance n'ont pas d'influence sur la production laitière.
The current annual increase of meat and milk consumption in Tanzania is 67%, due to rises in population and in national income. The increase greatly exceeds the annual national herd growth rate of 2.14%. Per capita milk consumption was estimated at 22.4 litres in 1983 (Anon, 1983) and is expected to rise to 28.0 litres in 1990. There are thus acute shortages of animal protein despite the national livestock population of 12.5 million cattle, 6.4 million goats, 3.0 million sheep, 0.3 million pigs and 13.6 million poultry (Anon, 1986).
Cattle are the main source of milk but in some areas goats are also milked. In the early 1960s exotic dairy goats were introduced with the objective of supplying milk in hilly or semi-arid areas where rearing dairy cattle may not be economical. The preliminary results of a study carried out to evaluate milk production by blended goats are presented in this paper.
Study sites
The 2 sites, Kongwa (central Tanzania) and Malya (western Tanzania), have a semi-arid climate. Natural vegetation is savanna grassland (Commiphora and Combretum woody species and Eragrostis, Aristida, Bothriochloa, Hyparrhenia, Themeda, and Cynodon grasses). Paddocks at Malya are sown to Chloris gayana, and to Cenchrus ciliaris with a few plots of Siratro and Leucaena leucocephala at Kongwa.
Animals and management
Blended goats are 3-way crosses with 55% Kamorai, 30% Boer and 15% indigenous blood (Des, in press). Phenotypically they have large pendulous ears and resemble Anglo-nubians. A total of 222 blended does (139 from Malya and 83 from Kongwa) were randomly selected, within the age range of 1 yr to 8 yr.
Does were bred twice a year with mating seasons of 70 d each in the dry (Sep-Nov) and wet seasons (Mar-May). Buck: doe ratio was 1:30. Kids were allowed to suckle in the morning and milking was done in the evening. Does were milked twice a day after kids were weaned. Kids were reared indoors and were provided with fodder, water, and concentrates ad libitum until weaning at 16 wk. After weaning, kids grazed natural pastures (08:00 to 15:00) and were given a daily concentrate ration (maize bran and cotton seed cake) of 50 g. Routine disease control measures included vaccination, dipping and deworming. Does were bred for the first time at 18 mot
Data recording and analysis
Kids were weighed at birth, weaning, 24 wk. 48 wk and 72 wk. Does were weighed at mating and kidding. Pre-weaning daily milk was estimated by doubling evening milk yield. Parameters measured included reproductive performance, weight at age and lactation performance. The reproductive indices were:
A linear model (Snedecor and Cochran, 1980) was used for analysing weight at age and milk yield. The linear model included the fixed effects of birth type (single, twin), sex (male, female), dam age (2-3 yr, 4-5 yr, > 5 yr) and interactions of some of the main effects.
At both sites older does had better reproductive performance than younger ones (Table 1). Weights of does at Malya (32.1 kg) exceeded those at Kongwa (29.3 kg) by 9.0% at mating and by 11.5% (34.3 kg v 30.3 kg) at kidding (Table 2). The differences in mating and post-partum weights between the age groups of does were significant (P < 0.05) within each centre.
Mean birth weight of all kids at both sites was 2.47 ± 0.03 kg (Table 3). Kids born at Kongwa were heavier than those at Malya by 3.55%. Twins were lighter than singles except for birth weight at Kongwa. Males were heavier than females at birth at Malya but not at Kongwa. Males were heavier than females at both stations at weaning. The age of the dam did not influence the weight of her offspring. There was a significant (P < 0.01) interaction between dam age and type of birth on birth weight at Kongwa: neither of the interactions, type of birth x sex and sex x dam age, were significant.
Table 1. Reproductive indices of blended does at two stations in Tanzania.
|
Station and trait |
Doe age (yr) |
Overall |
||||||
|
n |
2-3 |
n |
4-5 |
n |
>5 |
|||
|
Kongwa |
|
|
|
|
|
|
|
|
|
|
Apparent fertility rate (%) |
53 |
50.9 |
19 |
73.7 |
11 |
72.7 |
59.0 |
|
|
Fecundity rate (%) |
53 |
52.8 |
19 |
115.8 |
11 |
172.7 |
83.1 |
|
|
Prolificacy rate (%) |
27 |
103.7 |
14 |
157.1 |
8 |
137.5 |
140.8 |
|
|
Litter size (no) |
27 |
1.04 |
14 |
1.57 |
8 |
1.38 |
1.41 |
|
Malya |
|
|
|
|
|
|
|
|
|
|
Apparent fertility rate (%) |
48 |
45.8 |
64 |
78.1 |
27 |
85.2 |
68.3 |
|
|
Fecundity rate (%) |
48 |
54.2 |
64 |
103.1 |
27 |
122.2 |
89.9 |
|
|
Prolificacy rate (%) |
22 |
118.2 |
50 |
132.0 |
23 |
143.5 |
131.6 |
|
|
Litter size (no) |
22 |
1.18 |
50 |
1.32 |
23 |
1.43 |
1.32 |
Table 2. Weights (kg) at mating and postpartum of Tanzania blended does.
|
Station and doe age (yr) |
Mating weight |
Postpartum weight |
|||
|
n |
x |
n |
x |
||
|
Overall |
222 |
31.1 |
144 |
32.9 |
|
|
|
s.e. |
0.43 |
|
0.65 |
|
|
Kongwa |
|
|
|
|
|
|
|
2 - 3 |
53 |
19.9a |
27 |
26.5a |
|
|
4 - 5 |
19 |
32.4b |
14 |
32.2b |
|
|
> 5 |
11 |
35.4b |
8 |
32.3b |
|
|
Average s.e. |
|
1.47 |
|
0.71 |
|
Malya |
|
|
|
|
|
|
|
2 - 3 |
48 |
28.1a |
22 |
29.6a |
|
|
4 - 5 |
64 |
30.2b |
50 |
33.2b |
|
|
> 5 |
27 |
34.5b |
23 |
36.2b |
|
|
Average s.e. |
|
0.52 |
|
0.65 |
Within stations, and in the same column, values without a suffix letter in common differ (P < 0.05).
Milk recording was done at Kongwa only: 48 does were milked during the first 112 d (pre-weaning) but only 36 does were milked during the postweaning period. Mean preweaning milk yield was 37.6 ± 2.65 kg, postweaning yield was 85.3 ± 7.36 kg and total yield was 120.3 ± 8.72 kg. Lactation length was 266.0 ± 2.14 d and butter fat content 2.71%. Type of parturition and age at kidding did not affect any of the components of the lactation.
Table 3. Birth and weaning weights (kg) of blended kids at two stations in Tanzania.
|
Variable
|
|
Kongwa |
Malya |
||||||
|
Birth weight |
Weaning weight |
Birth weight |
Weaning weight |
||||||
|
n |
|
n |
|
n |
|
n |
|
||
|
Overall |
|
69 |
2.53 |
53 |
8.7 |
125 |
2.44 |
122 |
10.0 |
|
|
s.e. |
|
0.07 |
|
0.29 |
|
0.04 |
|
0.18 |
|
Type of birth: |
single |
28 |
2.84a |
27 |
9.0a |
60 |
2.61 |
60 |
10.8a |
|
|
twin |
41 |
2.32b |
26 |
8.5b |
65 |
2.29 |
62 |
9.3b |
|
Average s.e. |
|
|
0.09 |
|
0.38 |
|
0.09 |
|
0.25 |
|
Sex: |
female |
25 |
2.57 |
21 |
7.7a |
59 |
2.36a |
57 |
8.2a |
|
|
male |
44 |
2.56 |
32 |
9.3b |
66 |
2.52b |
65 |
11.6b |
|
Average s.e. |
|
|
0.08 |
|
0.39 |
|
0.05 |
|
0.27 |
|
Age of dam: (yr) |
2 - 3 |
28 |
2.50 |
21 |
9.0 |
26 |
2.51 |
25 |
9.1 |
|
|
4 - 5 |
30 |
2.63 |
21 |
8.7 |
66 |
2.40 |
64 |
10.0 |
|
|
> 5 |
11 |
2.47 |
11 |
8.3 |
33 |
2.48 |
33 |
10.7 |
|
Average s.e. |
|
|
0.09 |
|
0.50 |
|
0.07 |
|
0.34 |
Within variable groups, and in the same column, values without a suffix letter in common differ (P < 0.05).
Daily yield of blended does milked over 266 d was 0.4 kg/d, which is much lower than that reported for Indian goats (Barbari 0.87 kg, Jamnapari 1.01 kg; Mittal and Pandey, 1972) and for Sudanese-Nubian goats (1.01-1.25 kg; Sands and McDowell, 1978). Lactation yield in the present study is lower than that reported for Jamnapari (544 kg in 250 d) and for Barbari goats (592 kg in 177 d; NDRI, 1976). Variation in yield by parturition type was not observed in this study although a positive correlation between number of kids born and milk production has been noted elsewhere. Effect of doe age on milk production was not significant in the current experiment, in contrast to other studies where age had a significant effect on milk production with lowest yield in the first lactation (Mackenzie, 1970). Low lactation milk yield of blended goats could be due to low genetic potential for milk production from the mainly Boer blood which went into this breed. Average fat content from milk of blended goats (2.71%) is lower than that of West African goats (3.34-7.78%; Sands and McDowell, 1978).
Most livestock farmers in semi-arid central and northern Tanzania depend mainly on indigenous cattle milk as goat lactation yield is low (50-150 kg). With the introduction of crossbreds it is hoped that goat milk production can be made adequate throughout the year for family consumption and also provide a marketable surplus to improve the economic status of goat keepers.
The International Foundation for Science financed part of this study. The Director General, Tanzania Livestock Research Organization, is thanked for his support.
Anon 1983. The livestock policy of Tanzania. Ministry of Livestock Development, Dar-es-Salaam, Tanzania.
Anon 1986. Unofficial draft of livestock census (1984). Ministry of Agriculture and Livestock Development. Dar-es-Salaam, Tanzania (mimeo).
Das S M. in press. Growth and reproductive performance of blended goats in Malya, Tanzania. Tanzania Veterinary Bulletin.
Mackenzie D. 1970. Goat husbandry (3rd edition). Faber and Faber Ltd. London, England.
Mittal J P and Pandley M D. 1972. The yield and chemical composition of milk in Barbari and Jamnapari goats. Agra University Journal of Research (Science) 20(3): 7-12.
NDRI 1976. Management practices for goats. National Dairy Research Institute, Karnal, India.
Sands M and McDowell R E. 1978. The potential of the goat for milk production in the tropics. Cornell International Agriculture Mimeograph No. 60. Cornell University, Ithaca, USA.
Snedecor W G and Cochran G W. 1980. Statistical methods (8th edition). Iowa State University Press, Ames, USA.
