Studies on productive and reproductive performance of crossbred dairy cattle in selected Urban and Peri Urban Areas of Tanzania

Abstract

In Tanzania, urban and peri urban dairying is commonly practiced by people from different socio-economic and cultural groups. This provides them regular income, employment opportunities and alleviates poverty. The demand for milk and milk products is high and this motivates farmers to increase their cattle herds in urban and peri urban areas. Despite the high demand for milk and milk products, the average daily milk yield, quality of milk and reproductive performance of crossbred dairy cows is low due to management factors, poor quality feeds and feeding of the dairy cattle. In order to address some of the challenges to high milk production and reproduction performance of cows, a series of studies were undertaken in urban and peri urban areas of Dar es Salaam city and Morogoro municipality. In this study an in-depth literature review on urban and peri urban dairy farming in East African cities was done (Paper I). The results revealed that urban and peri urban dairy production system is very common in all East African cities but significantly varying in intensity. Dairy cows were fed on forages that contained 6 to 6.8%CP and produced average milk yield that ranges from 5.7–17.1 litres/cow/day. The range for lactation lengths, ages at first calving, calving to conception interval, calving interval and number of services per conception of crossbred dairy cows were 8.8 to 11.2 months, 29.7 to 46.0 months, 123 to 276 days, 406 to 562 days and 1.7 to 2.3, respectively. The trend in average milk yield and reproductive performance of the dairy cows was not clear. The major constraints hindering dairy production in East African cities differed between and within countries and production systems due to differences in data collection, physical locations, dairy breeds kept and seasons of the year.

In the second study (Paper II and III), a cross sectional study using a random sample of 153 dairy farmers in Dar es Salaam city (71) and Morogoro municipality (82) was done by collecting data on management and production levels of dairy cattle. The two study sites fall under the same agro ecological zone and were meant to compare the performance of dairy cows. The results showed that one third of farmers practised free grazing system and dairy cows were mainly fed low quality forage and energy concentrate. Forage/fodder was collected from communal areas and dairy farmers in Dar es Salaam city covered significantly longer distance (14.7±1.2 km) than Morogoro municipality (3.07±1.2 km). Steaming up of dry cows was fairly common among dairy farmers in Dar es Salaam city but rarely done in Morogoro municipality. Artificial insemination service was not a common breeding method in the study areas. Over half of the cattle sheds had high stocking density and were poorly designed (Paper III). Dairy cows produced significantly higher average milk yield in Dar es Salaam city (10.5±1.2 litres/cow/day) than in Morogoro municipality (6.2±0.4 litres/cow/day). One third of the dairy farmers (29.2 percent of 153 respondents) planned to decrease their cattle herds, many of them from Morogoro municipality (16.0 percent of 153 respondents) due to shortage of feeds.

The third study (Papers IV) was based on a longitudinal study design in which 60 dairy farmers with a total of 309 dairy cattle were monitored for nine (9) months to assess effect of management on chemical composition of milk and to quantify the microbial load of raw milk. Dairy cows were monitored during the wet and dry seasons to capture seasonal effect on milk yield and quality. The results showed the average milk yield to be 7.0±0.1 litres/cow/day and was significantly affected by parity, stage of lactation, season of calving, employment status of the farmers and means used to collect forage from the sources to the dairy units. However, milk yield was not influenced by grazing systems, breeds of the cows and types of farm labour. Dairy cows in the third parity, dairy cows owned by self-employed farmers and dairy farmers who used bikes to collect forage produced 7.8±0.2, 7.5±0.5 and 6.7±0.5 litres/cow/day higher than dairy cows in other parities, dairy cows owned by government-employees and dairy farmers who used cars to collect forage, respectively. The wet season had significantly higher total bacterial counts (5.9±0.04 log10cfu/ml) and coliform counts (2.4±0.08 log10cfu/ml) than 5.7 ±0.04 log10cfu/ml and 2.0±0.08 log10cfu/ml bacterial counts and coliform counts, respectively observed in the dry season. However, grazing systems had no significant effect on microbial load. Stocking density significantly influenced total bacterial counts but not coliform counts. Further, employment status of the dairy farmers and source of farm labour had no effect on bacterial loads.

Lastly, study four (Paper V) evaluated the effects of pre partum concentrate supplementation on milk yield, milk chemical composition and reproduction of crossbred dairy cows. The cost of concentrate supplementation of different treatment groups was also analysed. In this study, 48 dry crossbred cows in their last stage of gestation were used and divided into three groups according to concentrate supplementation and lasted for 24 weeks of lactation. The first treatment group was fed 4 kg/day of home-made ration during pre- and post-partum period (HMR-PPP) while the second group was fed a similar amount as the first group, but during the post-partum period (HMR-PP) only. The third group was a control and was fed maize bran 4 kg/day during the post partum period only (MB-PP) and simulated the farm’s feeding practice. The results on this study have shown that dairy cows supplemented with home made ration during pre and post-partum had significantly higher (8.5±0.3 litres/cow/day) milk yield followed by post-partum supplemented cows (6.2±0.3 litres/cow/day) with home-made ration. The control group which simulated farm's feeding practices had the least milk yield (4.5 litres/cow/day). Concentrate supplementation had significant effect on percent total solids but not on percent butter fat and percent solids not fat. Effect of breed was significant on percent butter fat and percent total solids but not on percent solids not fat. Parity had a significant influence on percent total solids but not on percent butter fat and percent solids not fat. Breed had no significant effect on milk yield while parity significantly influenced milk yield. The supplementation regime and breed of dairy cows had no significant effect on number of services per conception, interval from calving to first insemination, interval from calving to conception and calving interval. Supplementing dairy cows with home made concentrates during both pre and post-partum periods was cost effective and economical compared to post-partum concentrate supplementation alone. It is concluded that the production levels are lower than 15 l/cow/day expected to be produced by crossbred dairy cows. However, the production levels can be improved through strategic concentrate supplementation coupled with good husbandry practices. The microbiological quality of the milk was relatively poor. There is a need therefore to train dairy farmers on dairy cattle husbandry and the importance of clean milk production in order to safe guard the consumers of milk and milk products.