Evaluation of performance of Kagera region herds of cattle

PhD Thesis

This study was carried out to evaluate the performance of Kagera region herds of cattle. Both indigenous and crossbred dairy cattle were studied. Also a survey was conducted on the production environments of Kagera herds of crossbred cattle. Average number of heads of cattle, weaning age and milk yield per cow per day were 4.1, 3.6 months and 9.5 litres, respectively. Farmers that used bulls and artificial insemination (Al), as breeding techniques, were 53.6% and 14.4%, respectively. Mean calf, heifer, cow and bull mortality rates in the indigenous herds were, 24.1, 3.4, 3.2 and 5.4 %, respectively. Calf mortality was remarkably (P < 0.001) influenced by production system, zone, year and Farmers Extension Centre (FEC). The overall calving rate was 37.0%. The mean birth weight of calves was 23.8 ± 0.07 kg. There was notable (P < 0.001) effect of sex, age of dam, season and year on birth weight. The average age at first calving (AFC) was 38.3 ±0.16 months. The influences of season, year and genetic group on AFC were significant. The overall mean calving interval (CI) was 483.4 ± 1.7 days. Year, parity, district and genetic group significantly (P < 0.001) influenced CI. Partial correlation coefficients between mean daily milk yield (DMY) and 100-day milk yield, 305-day milk yield and lactation milk yield (LMY) ranged from 0.51 to 0.92, 0.46 to 0.89 and 0.38 to 0.75, respectively. All correlations were significant. The overall mean 100-day MY, 305-day MY and LMY were 758.7 士 4.1 kg, 2014.0 ± 12.1 kg and 2275.0 ± 11.9 kg, respectively. Parity, year and the interaction between genetic group and district significantly (P < 0.001) affected these traits. The mean lactation length (LL) and dry period (DP) were 355.6 土 1.1 days and 128.8 ±1.4 days, respectively. The mean persistence indices for the middle third (Pi) and the last third (P2) were 0.87 ± 0.01 and 0.79 ±0.01, respectively. Heritability estimates for 100-day MY, 305-day MY, LMY, LL, DP, AFC and CI were 0.33, 0.39, 0.38, 0.01, 0.12, 0.11 and 0.12 respectively. Repeatability estimates for 100-day MY, 305-day MY, LMY, LL, DP and CI were 0.37, 0.41, 0.33, 0.14, 0.18 and 0.12, respectively. Predicted genetic progress in milk yield based on progeny testing and young bull schemes were 84.2 kg and 20.7 kg per year, respectively. It was concluded that the % Friesian crosses were better off in all traits studied compared to other genetic groups and that up-grading should not exceed that 1evel. F2 crosses performed poorly compared to F1 for all traits studied.

SUA-MU ENRECA/PHSL Project