Factors affecting calving intervals, extracted milk yield and lactation length of Teso cattle and their crosses with Sahiwal and Boran
The current study was aimed at evaluating factors that influence reproductive performance and extracted milk yield of Teso (T) cattle and their crosses with Sahiwal (S) and Boran (B) using data collected between 2000 and 2002. We used General Linear Models procedure of SAS for analysis. The overall mean calving interval was 453±1.06 days and that of F1(BxT) and F1(SxT) crosses were 44.6 and 61.3 days longer than the pure Teso cows. The overall means for extracted lactation milk yield and lactation length were 120+-3.4 litres and 173.6+_5.0 days, respectively. F1(SxT) crosses had longer lactation length than F1(BxT) crosses and pure Teso cows by 34.2 and 17.2 days, respectively. F1(SxT) crosses had significantly (p<0.01) higher extracted lactation milk yield (178.0 litres) than pure Teso cattle (127.7 litres) and F1(BxT) crosses (125.9 litres). No significant (P>0.05) difference in extracted milk yield was observed between F1(BxT) crosses and purebred Teso cattle. Cows calving in the dry season had higher (p<0.05) extracted lactation milk yield than those that calved in the wet season. Extracted milk yield of the third month after calving had high and significant correlations of 0.80 and 0.93 with 100-days milk yield and lactation milk yield respectively. We conclude that with respect to calving interval, Teso cows were better than the other genetic groups while F1(SxT) out-performed the others in extracted milk yield and lactation length.
Keywords: calving interval, extracted lactation milk yield, 100-days milk yield, lactation length
Tanzania Vet Journal Vol. 25 (2) 2008: pp. 96-105