The management of bovine reproduction in elite herds.
The management of bovine reproduction is the cornerstone of health provision in elite herds. Aims and objectives for reproductive performance should be herd specific and data to monitor progress should not only be frequently collected, but also analysed and reported. Strategic monitoring of animals should include a vaginal examination for evidence of uterine disease, as well as transrectal ultrasonography of the genital tract. There has been considerable advancement in our ability to intervene in the reproduction of cattle during the last 50 years. However, it is salutary to note that during this time fertility has consistently declined, despite increasing veterinary intervention. Most elite herds use artificial insemination and success depends on accurate detection of oestrus expression, but this appears to be less overt than 25 years ago. In addition, half the cattle have abnormal oestrous cycles after parturition and conception rates are decreasing by 1% per year. Risk factors for abnormal oestrous cycles include puerperal problems, negative energy balance, which can be evaluated by body condition scoring, and uterine disease. Bacterial contamination of the uterus is ubiquitous after parturition in cattle and disease disrupts ovarian follicle growth and function. Reproduction is also disrupted by stress associated with clinical disease, pain or a sub-optimal environment. The challenge for veterinarians providing reproduction control programmes to elite herds is to transfer our knowledge of the problems underlying subfertility to the farm, in order to provide effective solutions.
Sheldon
I Martin
IM
Department of Veterinary Clinical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, UK. msheldon@rvc.ac.uk
Wathes
D Claire
DC
Dobson
Hilary
H
D000818:Animals; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000503:physiopathology*; D004972:Estrus Detection; D005260:Female; D005298:Fertility / Q000502:physiology; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D008297:Male; D012098:Reproduction / Q000502:physiology*; D012307:Risk Factors