Skim milk progesterone profiles in relation to repeat breeding syndrome and conception in crossbred dairy cattle

Abstract

Role of progesterone deficiency in repeat breeding and conception failure in crossbreeding cattle was studied. Normal (10: G 1) and repeat breeding (20; G 2) cows were examined per rectally and inseminated at standing estrus with good quality frozen thawed semen. Milk samples were collected from each animal on days 0, 4, 6, 8, 12, 16 and 20 or 22 post~in5emination for progesterone (P) through RIA. All cows ofG 1 and 45% cows ofG 2 revealed normal skim milk P" profiles i.e. Pol concentration rose to I ng/ml or higher within 5 days of insemination and then steadily increased to 2 ng/ml or higher at mid luteal phase. Eight (40%) cows ofG 2 had Pol deficiency (OAO±O.06 to 0.60±0.06 ng/ml) in early luteal phase (within 6 days post-insemination) whereas, 10% cows of G 2 were late (from days J2- J6 post- insemination) luteal deticient (0.29±0.5 to O.59±O.11 ng/ml). One animal (5%) was P4 deficient (0.53 to 0.9 ng/ml) during mid luteal phase I.e, from day 6-12 post-insemination. The conception rate was 60% in G I and 20% in G 2 cows. It is concluded that luteal insufficiency appears to be an important cause of repeat breeding in cattle.