PLASMA PROGESTERONE AND BLOOD METABOLITE PROFILES IN POSTPARTUM SMALLEAST-AFRICAN ZEBU COWS

Plasma progesterone profiles were used to monitor post-partum reproduc tive activity in 12 Small East African zebu (Bos indicus) cows allocat ed to either supplementary or no supplementary feeding (control) with continuous or restricted (twice daily) suckling regimes. Intact bulls were used for breeding. Blood samples were collected 3 times a week fo r 33 weeks to determine plasma progesterone levels. Weekly blood sampl es were also used to determine blood metabolite concentrations. Plasma progesterone levels remained below 1 ng/ml in all cows until week 12 post-partum. Only 5 cows showed ovarian activity over the 33 week peri od. Cows that cycled expressed irregular and short-lived progesterone rises (> 1 ng/ml) lasting 8 to 12 days prior to establishment of norma l patterns of progesterone secretion where progesterone levels ranged from 8 to 10 ng/ml in cows with normal cycles. Plasma total protein, a lbumin, globulin, blood urea nitrogen and glucose levels varied over t ime without consistent trends, and were not influenced by either suppl ementary feeding of suckling regimes, nor differed between cyclic and acyclic cows. It was concluded that extended post-partum anoestrus, co nception failure and early embryonic mortality were responsible for lo wered reproductive efficiency in zebu cows. Blood metabolite concentra tions were not good indicators of nutritional status and were not rela ted to post-partum ovarian activity.