Twenty five smallholder dairy farmers and other stakeholders, through a Participatory Rural Appraisal in three wards of the Tanga township of north east coastal Tanzania, ranked their perceived constraints in descending order of importance: Low milk price and marketing, feed shortage in the dry season, poor management, low animal productivity, poor reproductive performance and diseases. Tick borne diseases were reported on a majority of farms. An Economic Opportunity Survey revealed wide ranges in management indices and improvement in annual milk production, age at first calving and lactation length to represent the best potential for gain. Performance generally was below locally set targets. Farmers spent on average in the three wards between 39% and 77% of income from milk on feed costs yearly. Interventions were instituted emphasising those that farmers could afford immediately. They included farmer training, dry season feed supplementation, tick control, improvement of animal shed/ house cleanliness and the formation of a cooperative for milk marketing. Partial budgeting is being used to monitor success. Follow-up meetings and regular visits to farms by field officers are disseminating information on outcomes to encourage farmers to continue with interventions and spread useful knowledge to friends and neighbours.

The objectives of this study were to assess changes in nutritional status/body condition score, percentage pregnancy and calving rate in Zebu cows and to establish the relationship between body condition score loss and postpartum interval to resumption of ovarian activity. A total of 198 cows and postpubertal heifers of the Tanzanian Shorthorn Zebu kept under a traditional management system were randomly selected from 200 smallholder herds. Factors investigated during bi-weekly visits include body condition score (BCS), heart-girth circumference, milk yield and reproductive status of the animals, pregnancy/nonpregnancy and cyclicity/non-cyclicity. Local weather conditions and dates of occurrence of other reproductive events such as calving were also recorded. Calvings occurred all year round but with a strong seasonal distribution characterized by annual peaks observed between April and July. The annual calving pattern was closely related to rainfall, with peak precipitation occurring a few months before peak calving. The overall percentage pregnancy varied from 30% to 50% throughout the year. Postpartum cows exhibited minimum mean BCS and heart-girth circumference 12-14 weeks after calving, and cows with BCS loss >1 point exhibited the longest time interval from calving to onset of ovarian activity.

The objective of this study was to monitor the reproductive performance of dairy cows in smallholder farms under the Tanga Dairy Development Project (TDDP). The findings can be used to improve reproductive efficiency. Dates of oestrus, artificial insemination (AI) or service by bull and calving were recorded, and pregnancy was diagnosed by rectal palpation. Daily milk yields, monthly body condition score (BCS) measured on the scale of 1-9, feed availability, calf rearing, and diseases were also recorded. Milk progesterone (P4) concentration was measured by radioimmunoassay (RIA) in 1327 sequential samples collected between day 15 and 120 in 46 post-partum Zebu x Friesian crossbred dairy cows. The mean interval from calving to first P4 rise above 2 nmol/L (cyclicity) was 66.1 +/- 6.8 days. Resumption of ovarian activity postpartum was early (< 60 days) in 45%, and late (> 60 days) in 55% of the cows. In about 45% of the cows the first post-partum ovarian cycles were short (< 14 days) and had low P4 concentrations. Oestrus was missed once or several times in 34.7% of the cows, most likely indicating poor oestrus detection, silent oestrus, or farmers deliberately not taking or reporting their cows for insemination. The mean interval to conception was within 130 days postpartum. Average daily milk production was 5.7 +/- 2.2 L and the mean BCS Was 3.1 +/- 1.3. Both milk production and BCS had no clear influence on the measured reproduction parameters. Clinical uterine involution was complete within 29 +/- 2.6 days of calving in the majority of cows. Progesterone profiles and rectal palpation revealed various causes of infertility, which included anoestrus, silent oestrus, irregular oestrous cycles, and infection of the uterus. The major causes of animal culling, death, slaughter or sales include tick-borne diseases and trypanosomiasis, which have high prevalences in the area, infertility, low productivity and old age. Greater attention should be focused on reproduction and its interaction with nutrition and disease control.

The effects of calcium (Ca), phosphorus (P) and zinc (Zn) supplementation on reproductive performance of grazing dairy cows was studied. Forty-eight cows in their first to third parity were allocated to eight groups of 6 animals each, based on stage of lactation and milk yield. Groups 1 (control), 2 (Ca), 3 (P) and 4 (Zn) received, respectively, no mineral supplement, 10 g Ca, 8 g P and 400 mg Zn. The rest of the groups received a combination of Ca/P, Ca/Zn, P/Zn or Ca/P/Zn. Animals were drenched daily. Ovarian activity was determined by progesterone concentrations in milk. Prepartum body condition score (BCS) measured using scale 1-5 was 2.5-3.5. Reproductive problems were observed in all groups except that supplemented with Ca. Cows supplemented with Ca, P, Ca/P, Ca/Zn and Ca/P/Zn had significantly (p < 0.05) shorter interval (30 days) from calving to resumption of oestrus as compared to control (69 days). Intervals from calving to conception and between calvings did not differ significantly between groups (p > 0.05), but were shorter in Ca-supplemented cows. Furthermore, cows in groups 2 and 3 needed an average of 2 services per conception against 3 for cows in other groups. Hence, supplementation with Ca, P and Zn of deficient dairy cows appears to improve reproductive performance.

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