title: Influence of suckling and continuous cow-calf association on the resumption of post-partum ovarian function in Bos indicus cows monitored by plasma progesterone profiles.
abstract: The effect of suckling on post-partum ovarian function was monitored by weekly plasma progesterone determinations using enzyme immunoassay in 16 Small East African Zebu (Bos indicus) cows maintained with a fertile bull. Five cows continuously suckled their calves (COS), but starting 30 d after calving 6 cows remained with their calves which were prevented from suckling using nose plates (NOS) while 5 calves were separated and penned (PEN). The mean (+/- SE) interval from calving to first behavioural oestrus was 81 +/- 11 d and was significantly (P less than 0.001) shorter for PEN (43 +/- 10 d) than NOS (72 +/- 9 d) or COS cows (133 +/- 11 d). COS cows nonetheless weaned heavier (P less than 0.001) calves at 5 months. Ovarian activity determined by plasma progesterone levels greater than or equal to 1.3 ng/ml indicated that "silent ovulation" was initiated in 44% of cows by 40 +/- 6 d post-partum. The results indicate that continuous suckling or constant cow-calf interaction extend the post-partum anoestrous interval in Ethiopian Zebu cows. However, early-weaned calves or those on restricted suckling would need extra nutritional supplementation to ensure continued growth.
authors.affiliation: Animal Reproduction and Health Section, International Livestock Centre for Africa (ILCA), Addis Ababa, Ethiopia.
authors.forename: E
authors.initials: E
authors.lastname: Mukasa-Mugerwa
authors.forename: A
authors.initials: A
authors.lastname: Tegegne
authors.forename: R
authors.initials: R
authors.lastname: Franceschini
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D007774:Lactation / Q000502:physiology*; D008425:Maternal Behavior; D010053:Ovary / Q000502:physiology*; D049590:Postpartum Period / Q000502:physiology; D011374:Progesterone / Q000097:blood*; D013997:Time Factors; D014886:Weaning
chemical_list: D011374:Progesterone