Factors Affecting the Reproductive Efficiency of Artificial Insemination Programmes in a Seasonal Breeding Pasture‐based Dairy System with the Aid of Milk Progesterone

• DOI: 10.1046/j.1439-0531.2001.00254.x
• Publication Date: 2003-03-12T19:10:12Z
• Authors: D Cavestany; CS Galina
• Keywords: 2. Zero hunger; Time Factors; Reproduction; Postpartum Period; Radioimmunoassay; 0402 animal and dairy science; 04 agricultural and veterinary sciences; Breeding; Anestrus; 3. Good health; Dairying; Parity; Milk; Animals; Uruguay; Cattle; Female; Seasons; Birth Rate; Estrus Detection; Insemination, Artificial; Progesterone

To determine the factors affecting reproductive efficiency in a seasonal breeding artificial insemination (AI) programme dairy herds Uruguay, field trial was conducted on three farms. Lactating cows (n=328) intended to be bred at following period were selected. The started 1 week before beginning of and lasted 80 days or until first service. Milk samples obtained biweekly for 12 weeks, starting prior season progesterone concentrations. Data indicated that 12.5% anoestrus remaining this condition throughout trial. Most anoestrous animals first‐calf heifers. A varying number cycling (8.5%) each farm never reported heat. Oestrous detection rate cycling, as determined by patterns, evaluated periods 21 resulted an overall 46.9%. Main oestrous farm, with effect parity (67.8%, mature 33.2%, heifers) no postpartum. Mean interval from 27.4 days, which also affected farm. Neither nor postpartum parameter.