The Effect of Some Reproductive and Productive Traits on Lactation Performance of Butana Cattle at Atbara Reseach Station

Abstract

This study was conducted to assess the effect of calving interval, age at first calving, lactation length and parity number on lactation yield, first 100-day milk yield & first 180-day milk yield on the 2nd and 3rd lactation of Butana cattle of the Sudan at Atbara Research Station covering the Years (1990-2001). The records were analyzed using spss computer programmes. The least square means for lactation milk yield, first 100-day milk yield, first 180- day milk yield, age at first calving, calving interval and lactation length were 1942.49 ± 117.65 kg, 812.52 ± 50.66 kg, 1363.18 ± 78.08 kg, 45.09 ± 3.56 month, 382.38 ± 8.30 days and 268.17 ± 5.56 days respectively. The analysis of variance revealed that the calving interval, age at first calving and lactation length influenced the second lactation milk yield (p<0.05). While calving interval has significant effect (p<0.05) on 2nd lactation first 100-day milk yield and highly significant (p<0.01) effect on 2nd lactation first 180-day milk yield. Age at first calving had no significant effect on 2nd lactation first 100-day milk yield and first 180- day milk yield. Lactation length did not significantly affect the 2nd lactation first 100-day milk yield but affected the 2nd lactation first 180-day milk yield. The statistical analysis showed that the calving interval did not significantly (p>0.05) affect the third lactation milk yield, first 100- day milk yield and first 180-day milk yield. Age at first calving had a significant (p<0.05) effect on 3rd lactation milk yield and first 180- day milk yield but non significant effect on first 100- day milk yield. Regarding, lactation length and lactation number the result showed documented highly significant (p<0.05) effect on first 100- day milk yield and first 180- day milk yield on the 3rd lactation. The linear and quadratic regression on age at first calving and lactation length revealed a significant influence on the lactation yield & first 180- day milk yield in both 2nd and 3rd lactation, but a non significant effect on first 100- day milk yield in 2nd lactation. The lactation length on the other hand exerted a highly significant effect on the first 100-day milk yield in the 3rd lactation. Parity number had a significant effect on total milk yield, first 100- day milk yield and first 180- day milk yield for the 3rd lactation. The overall correlation co- efficient between milk yield, lactation length, first 100- day milk yield , first 180- day milk yield and calving interval were found to be 0.68, 0.63, 0.79, and 0.11 respectively. While the correlation between lactation length, first 100- day milk yield, first 180-day milk yield and calving interval were 0.20, 0.35 and 0.16 respectively