Abstract
Abstract Average conception rate (C.R. = 49-day non-return rate) from semen of 12 bulls in one region was 68.3% compared with 59.8%, for the same in another region. C.R. differences between the regions were less for sires of above-average fertility than for below-average sires. C.R. increased by 0.14% per day in one region and by 0.17% per day in another region from early September to mid December, accounting for over 40% of variation in C.R.s for individual collections. Sire differences in fertility accounted for only 9% of variation in one region and 17% in the other. Records for 51 208 inseminations using semen from 19 sires were classified into: cows diagnosed in oestrus before or during an evening milking on the day before insemination (p.m. cows); and cows diagnosed before or during the morning milking on the day of insemination (a.m. cows). Almost all cows were inseminated between 8.00 a.m. and 12 noon. C.R.s were highest when a.m. cows were inseminated with semen from sires of above-average fertil...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
