Department of Animal Sciences-Journal Articles
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- ItemOpen AccessThe Effect of Environment on Reproductive Performance of Dairy Cattle in South Western Nigeria(Faculty of Agriculture, University of Ife, 1982) Somade, B.The effect of environment on the reproductive performance of 50 Holstein cows at the Iwo Road Dairy Farm of Oyo State, Nigeria, was evaluated by summarising and analysing data collected on the cows over a seven year period (January 1970 to December 1976).Two main seasons were discernible from the rainfall and temperature data: (i) the dry season with a mean rainfall of 36mm and mean maximum and minimum temperatures of 31.6oC and 22.3oC respective1y;and (ii) the wet season with a mean rainfall of 176 mm and mean maximum and minimum temperatures of 29.s0c and 22.7% respectively. These seasonal variations adversely affected reproductive performance. Data collected for the dry and wet seasons respectively were: services per conception, 3.7.and 2.5; number of conceptions, 35 and 121; first oestrus after calving, 61 and 50;days from first service to conception, 64 and 52; and number of claves born, 53 and 91.
- ItemOpen AccessEffects of Age of Cow at First calving, Period of Calving and Calving Sequence on Calving Interval of N’dama and Keteku Cattle, and their Crosses in Southwestern Nigeria(Faculty of Agriculture, University of Ife, 1982) Akinokun, O.Calving records of N'darna and Keteku cows on range in the humid tropical environment of southwestern Nigeria were analysed to determine the effects of cow age at first calving, period of calving and calving sequence on length of calving intervals. Cow age at first calving and calving sequence significantly affected calving intervals (P < .01). Heifers calving for the first time at 3.6 - 4 years had an average calving interval of 511 days while heifers calving for the first time before 3.6 years had intervals that were 36 days longer. Those calving for the first time at over four years had average calving intervals that were shorter by 73 days. There was a progressive decrease in length of calving interval as calving sequence increased. Period of calving had no significant effect on length of calving interval.