Changes of Stayability, Milk and Calf Production in Friesians, in Egyptian Environments

Abstract

Data on 1691 lactations of 407 Friesian cows during the period l978-1988 were classified into two groups. The  first was composed of the dams imported from Holland. The second included their female offsprings locally bom in  Egypt. Records were analysed by general linear models for stayability, first lactation milk yield (FMY), total  milk yield and calf production up to five years of age (TMY5 & CPS) and total milk yield to five years without  first lactation milk yield (TMY5-1). The results showed that the averages of survival rates up to 48, 60, 72 months of age were 50, 41 and 22 % for all Friesian cows studied. The stayability values were lower in locally born than in the  imported animals, but the differences were not significant eitha for 36-48 or 60-72 months of age. The regression coefficients of stayability for 36-48 months on age at first calving and FMY were negative (-016 and  -0.0002, respectively) and significant (P<0.01 and 0.05, respectively). FMY and CP5 were non significantly and  TMY5 and TMY5-1 were significantly (P<0.01) higher in imported than in locally bom cows. Year-season of first calving  showed highly significant (P<0.01) effects on FMY, TMY5, CPS and TMY5-1. The FMY, TMY5, CPS and TMY5-1 decreased  between the years 1981 and 1985. The regression coefficients of FMY of offspring on those of dams in Holland,  Egypt and both together were not significant. The effect of age at first calving on TMY5 was significant (P<0.05) and  the effect of FMY on each of TMY5 and TMY5-1 was highly significant (P<0.01).