An analysis of the variation of the lactation curve of small East African goats

Abstract

Lactation curves were fitted to 267 lactations from Small East African goats kept under arid and semi-arid pastoral conditions. The lactations were recorded over a period of 4 years between 1984 and 1987. Parameters obtained from fitting the equation of Wood (1967) (Y(t) = Atbe−ct) were subjected to statistical analysis. The factors analyzed included vegetation, parity, year, litter size, weight and age of the doe. The parameters described various sections of the lactation curve, that is, the level of yield (intercept) (A), the ascending phase to a peak (b) and the descending phase to drying up (c). Vegetation (P < 0.01) and year (P < 0.05) significantly influenced the three parameters of the lactation, while parity, litter size and doe weight only influenced (P < 0.01) level of production. Lactation curves were constructed from the parameters obtained from fitting the equation