Milk production potential of free ranging shall East African goats.

Abstract

Analyses of milk production ability of the Small East African goats were performed on data collected at Isiolo Animal Production Station in Isiolo District of Kenya. The data were collected from 93 does which kidded in 1984 and 1985, and 140 kids (70 singles and 35 twins). All the lactations were analysed but only 56 were complete. The animals from which the data were collected grazed and browsed on the natural rangeland pasture in the Livestock Marketing Division holding ground. The liveweights (kg), milk yields (ml), and vegetation condition assessment data were recorded fortnightly while birth and deaths were recorded as they occurred. The analyses carried out were normal distribution statistics, analysis of factors affecting the daily milk yield and fitting of an algebraic function to the lactation data for the purpose of describing the lactation curve of the Small East African goat. The least squares methodof analysis was used for the factor analysis and the fitting of the curve. The function fitted was, Yt=Atbe-ctft, where Yt is the daily milk production in period t of lactation. A is the general level of production. band c are constants describing the rise and decline of daily milk production. e is the natural logarithm. ft is an adjustment factor for the variation in daily milk yield in period t of lactation. The mean daily milk yield of the does was 287.86 + 5.42 mI. The mean lactation yield was 55.41 ± 5.103 litres in an average lactation period of 31.4 + 1.5 weeks. The daily milk yield was significantly affected by litter size (P<O.OOl), vegetation condition (P<O.OOl), year (P<O.OOl), survival of the single kid (P<O.OOl), dam age (P<0.05), dam weight (P<O.OOl) and period of lactation (P<O.OOl). Sex of the kids and dam weight change did not significantly affect the daily milk yield. The mathematical function which was fitted to the lactation data produced a good fit. The multiple coefficient of determination was 99.2% before adjusting for the intercept and 46.28% after. The least square estimates of In A, b, and c were 0.92, -0.0098 and 0.00238 respectively. The b value was close to O. The study indicated large variation in the milk production potential of Small East African goats.