Effect of Physiological Status and Season of Calving on Milk Yield, Milk Composition and Blood Constituents

Abstract

Experiments were performed, between (August 2004) and (November 2005) at a Dairy Farm, Shambat, area Sudan, to study the effects of parity number, stage of lactation and season of calving on milk yield, milk .composition and constituents of blood Milk yield varied significantly (P<0.01) with the parity number and stage of .lactation (P<0.01) only Milk total solids, fat, total proteins, solid not fat, Na, K, and Po4 varied significantly (P<0.05) with the stage of lactation as well as with the season of calving, while the milk ash, moisture and calcium content were not affected by stage of lactation and season The highest concentrations of blood total proteins, albumin (P<0.01) and glucose (P<0.05) were obtained from animals at the first and second stages of lactation and the lowest were obtained from animals at late stages of lactation . The opposite was true for blood content of Na, K, Mg and Po4 Second parity animals had significantly higher values for haemoglobin concentration(P<0.01) and packed cell volume (P<0.05) than the first parity animals. Erythrocyte and total leucocyte count were not affected by the parity .number