Assessment of reproductive performance of smallholder dairy cattle in Rungwe district, Tanzania and possible interventions
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Date
2006
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Sokoine University of Agriculture
Abstract
A study was conducted aimed at establishing causes for suboptimal reproductive
performance in smallholder dairy cattle and investigate on possible interventions.
Experiment 1 was carried out to identify management, productive and reproductive
status of the animals. The data were analysed using descriptive and Chi-square
test. Monitoring was done (Experiment 2) to evaluate nutritional, productive and
reproductive status of animals. Body weight (BWT), body condition score (BCS),
plasma urea nitrogen (PUN), calcium (Ca), phosphorus (P) and copper (Cu) were
determined. Several reproductive performance indices were calculated and
association between them and the nutritional parameters were determined by
Pearson’s correlation coefficients. Effect of supplementation on productive and
reproductive performance was evaluated (Experiment 3) using similar parameters
as in experiment 2. General linear model was applied for analysis of variance of
variables in experiments 2 and 3. Chi-square test was used to determine the
relationship between proportions of animals in categories of reproductive
parameters and diseases in different seasons and treatment groups. Experiment 1
showed that most respondents practised zero grazing, bred animals by natural
mating and dried cows 1-3 months precalving without steaming up. On average
farmers fed 1.9 kg of concentrate per day for 19.2 days in a month with 23.8 g/day
of minerals included in 13.7 days in a month. The observed (Means ± SD) ages at
puberty, first mating, first calving (AFC) and CI were 20.5±1.0, 21.5±1.8,30.8±1.8 months and 526±123 days, respectively. In experiment 2, BWT and BCS
(Means ± SEM) were 320.8 ± 3.9 kg and 2.2 ± 0.0, respectively. Concentrations
(Means ± SEM) of PUN, plasma Ca, P and Cu were 8.4 ± 0.2, 7.7 ± 0.1, 4.3 ±0.1
mg/dl and 0.44 ± 0.01 pg/ml, respectively. Ovarian cyclicity resumed before 90 days
postpartum in 29.4% of the animals and days to first visual oestrus (DPO) were 178.7
±19.6 (Mean ± SEM) with 22.9% of cows showing visual oestrus before 90 days
postpartum. Mean (Mean ± SEM) SC and CI were 1.5 ± 1.2 and 485.7 ± 20.1 days,
respectively. The DPO was significantly correlated with BWT (r = -0.315; P<0.05),
BCS (r = -0.424; P<0.01) and body condition score at calving (BCSC) (r — -0.348;
P<0.05) while CI was significantly correlated with BCS (r = -0.394; P<0.05).
Supplementation significantly (P<0.05) reduced DPO by 43.6 days and significantly
(P<0.001) improved BWT, BCS, PUN, and milk yield by 37.9 kg, 0.3, 2.2 mg/dl, and
2.5 L/day, respectively. In addition, supplementation significantly (P<0.05) increased
BCSC, plasma P, Cu, and calf birth weight by 0.4, 0.6 mg/dl, 0.07 pg/ml, and 2.6 kg
respectively. Reproductive performance of the cattle was suboptimal and was
attributed to nutritional deficiencies. Concentrate supplementation and body
condition scoring were recommended but further research is needed to refine the
feeding strategy in relation to plasma P and Cu and to establish the optimum body
condition score for daily cattle production and reproduction in the area. More
research is also needed to identify risk factors that contribute to cattle dystocia in
Rungwe district.
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Keywords
Assessment of reproductive, Smallholder, Dairy cattle, Rungwe district, Tanzania