Abstract

1031 lactation records produced by 304 Friesian cows during 1978- 1982 at the April 7th State Farm were analysed by the le a st squares method* The cows included those imported as pregnant heifers from Holland and their locally-born daughters* Their 305-day milk yield averaged 3983 and 3028 kg resp ective ly ( p < * 0 l) , and was affected by age at first calving (p < *0 5 ), and each of proceeding dry period service period and calving interval (p < *0 1 )* Maximum y ie ld was associated w ith ages at f ir s t ca lvin g o f 781-850 days, dry periods o f 31—60 days, service periods o f 30—6© days and calving intervals of 481-540 days* Yield increased t i l l the 4th lactatio n (p < * 0 l) and was affeoted by month and year of calving (p < *0 1 )* Whereas, the effect of calving interval lacked significance * 60- and 305- day yields were correlated (r= *75, p <*01) and th e ir re p e a ta b ility were *287 and *18 3 respectively* 

K. H Juma, S. H Jajo

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume XI. Genetics of reproduction, lactation, growth, adaptation, disease, and parasite resistance., , 520–523, 1986
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