Authors : Ogundu , Uduak E., U. Herbert and M. U. Iloeje
Abstract: Using records of a total of 472 daughters, comprising 237 and 235 daughters with 25% and 50% Friesian inheritance respectively, 18 widely used bulls were evaluated by modified contemporary comparison (MCC) for first and second lactations. The daughters were classified into three age classes 24-28 months, 29 - 33 months and 34-38 months. The mean predicted differences for first and second lactation yield (PDLY1 and PDLY2) for the age class 24-28months was 2.8 (0.19) (PDLY1) and 3.8 (4.73) (PDLY2) for 25% and 50% Friesian inheritance respectively. The results obtained show that daughters of the 24-28 months age range had higher mean values for lactation yield when compared with their contemporaries suggesting that they could possibly transmit this superior milking ability. The linear response in PDLY2 to rate of change in PDLY1 in 25% (50%) Friesian inheritance indicated a significant (P<0.05) linear relationship between PDLY1 and PDLY2. The regression model accounted for 65% (20.1%) of the total variability in PDLY2. Prediction of PDLY2 from PDLY1 in 25% Friesian group shows that selection of sires on the basis of their daughters` higher first lactation yield could bring about a higher second lactation yield. Hence, judging from the performance of the age group 24-28 months, selection within PDLY1 forthat group could bring about an improvement in PDLY1.
Ogundu , Uduak E., , U. Herbert and M. U. Iloeje , 2004. Modified Contemporary Comparison of First And Second Lactations In A Herd with Crossbred Bunaji X Friesian Cows . Journal of Animal and Veterinary Advances, 3: 670-673.