title: An investigation into the causes of low calving percentage in communally grazed cattle in Jericho, North West Province.
abstract: The communal grazing system is generally understood to have a low input, low output type of management. However, the actual inputs and outputs of the farmers are not well known and the farmers are often unaware of their problems. Although the causes of low calving percentage are well understood in commercial beef farming enterprises in South Africa, the same is not true for communal farming systems. The aim of this study was to determine the reproductive performance of beef cattle on a communal farming system in Jericho, North West Province. Ten farmers from five villages with a total of 265 cows and 13 bulls were purposively selected. The selection criteria were that each farmer had to have a minimum of 10 breeding cows and a bull and be willing to participate in the study. This was followed by a 12-month longitudinal study with monthly herd visits where cows were examined rectally and bulls (n = 13) were subjected to a single breeding soundness evaluation. The calving percentage was found to be 37.7%. This is lower than the recorded percentages for commercial beef cattle on extensive grazing. The factors playing a role in low calving percentage were ranked using field data. From this it appeared that failure of cows to become pregnant was the main cause of poor calving percentage as opposed of loss of calves through abortion or resorption. Sub-fertility of the bulls was found to be of great significance and it is proposed that this be included in extension messages and that bulls be fertility tested routinely. Poor body condition score of cows, mainly caused by poor management, was also considered to play a major role in reducing pregnancy rates. Infectious diseases like trichomonosis, campylobacteriosis and brucellosis played a much leser role than anticipated.
authors.affiliation: Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa.
authors.forename: E
authors.initials: E
authors.lastname: Mokantla
authors.forename: C M E
authors.initials: CM
authors.lastname: McCrindle
authors.forename: J P
authors.initials: JP
authors.lastname: Sebei
authors.forename: R
authors.initials: R
authors.lastname: Owen
mesh_terms: D000034:Abortion, Veterinary / Q000453:epidemiology; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D000831:Animals, Newborn; D001824:Body Constitution / Q000502:physiology; D002417:Cattle / Q000502:physiology*; D005260:Female; D007246:Infertility / Q000209:etiology / Q000662:veterinary*; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D011270:Pregnancy, Animal / Q000502:physiology*; D012098:Reproduction / Q000502:physiology; D013019:South Africa; D013094:Spermatozoa / Q000502:physiology