Abstract:
This study was carried out to evaluate the current performance of dairy cattle at
ASAS and Kitulo farms in the Southern Highlands of Tanzania. The objective was to
assess the effects of genetic and non-genetic factors on lactation and reproductive
performance, calf mortality rate, longevity traits and constraints affecting
performance of dairy animals. Ayrshire and Friesian cows were involved in the study.
Data were analysed using General Linear Models procedure of Statistical Analysis
System (SAS). Average ages at first calving (AFC) at ASAS farm were 1059.5 }19.41
and 1105.7 }12.99 days for Ayrshires and Friesians, respectively. Breed and calving
period significantly (P < 0.05) influenced AFC. At Kitulo farm AFC was
1151.7 }9.63 days. Both parity and period of calving significantly (P < 0.001)
influenced CI. Mean calving intervals (CI) at ASAS farms were 410.8 }8.1 and
423.4 }6.8 days for Ayrshire and Friesian cows, respectively. At Kitulo farm mean CI
was 421.6 }1.43 days. Mean lactation milk yields (LMY), lactation lengths (LL) and
dry periods (DP) at the ASAS farm were 2696.8 }75.4kg, 305.8 }5.7 and 92.9 }2.6
days, and 3000.1 }62.9kg, 318.7 }4.8 and 96.3 }2.2 days for Ayrshires and Friesians,
respectively. Breed (P < 0.001), parity (P < 0.001) and period of calving (P < 0.05)
significantly influenced LMY and DP. At Kitulo farm mean LMY, LL and DP were
2608.3 }24.0 kg, 322.3 }1.4 and 91.2 }0.52 days. Only period had a significant (P <
0.01) effect on LL. Overall abortion, stillbirth, pre-weaning and post-weaning
mortality rates were 4.8, 3.7, 6.5 and 11.0% for ASAS farm. Corresponding rates at
Kitulo farm were 11.2, 7.6, 12.1 and 13.0%. Mean lifetime milk production at ASAS
farm for Ayrshires and Friesians were 11 303.6 and 13 517.5 kg while at Kitulo farm
it was 13 481.2 kg. Management improvement including testing and vaccination of
heifers against brucellosis and rehabilitation of infrastructures is therefore
recommended.
