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.
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.
Mukasa-Mugerwa
E
E
Animal Reproduction and Health Section, International Livestock Centre for Africa (ILCA), Addis Ababa, Ethiopia.
Tegegne
A
A
Franceschini
R
R
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
D011374:Progesterone