Factors affecting the reproductive profile of cattle in the semi-arid region of Algeria

Reproduction is one of the most important factors limiting dairy cattle production. Early resumption of ovarian cyclicity postpartum is important to helps cows to conceive early in this critical period. This study aimed to investigate the profiles of resumption of ovarian cyclicity postpartum in Montbeliarde dairy cows under semi-arid environment .Milk samples taken thrice weekly from 30 to 60 days postpartum and progesterone concentrations in skim milk were determined by Chimiluminescent Immuno Assay. Onset of luteal activity (OLA) was defined as the first day milk progesterone concentration ≥ 1 ng.mL-1for two successive measurements. Progesterone profile were classified as: Normal cyclicity; 52.3 % (n = 68/130) and delayed resumption (delayed first ovulation) 47.7 % (n = 62/130). The body condition score (BCS) of cows, class pf parity, calving season and class of conception rate are factors of variation that affect (p<0,000) the profiles of postpartum resumption ovarian activity.