The need to optimize rather than maximize rates of reproduction has been demonstrated for various production situations. In a highly intensive system, incorporating the use of artificial insemination, increasing the calving rate from 75 to 85% did not yield more…
The influence of energy supplementation (2,8 kg maize meal) of beef cows during early lactation and of creep feeding their suckling calves was investigated in two areas (Thornveld and Transitional Highland Sourveld). The cows were bred in spring to calve…
Shorthorn and Bonsmara type beef heifers from two breeding seasons were allocated to a high (H), medium (M) and low (L) level of nutrition after weaning at 7 months of age. The feeding levels were applied for 145 days (1972…
The effect of active immunization against androstenedione on reproductive performance was investigated in a flock of 151 Angora ewes. Although differences occurred between groups in some of the reproductive parameters recorded, the eventual number of kids produced was virtually the…
The effects of supplementary P (phosphorus) on the performance of cattle at two distinctly different experimental sites: one notorious for its P-deficient pastures (Armoedsvlakte), the other (Glen) suspected of being deficient in P, were compared over 5,5 years. The acuteness…
The influence of body parameters on the reproductive performance of Karakul ewes. The influence of body mass, condition and size on the reproduction of mature Karakul ewes was investigated during the seasonal anestrum and breeding periods. Variation in body mass…
Data of the Tygerhoek Merino flock were used to obtain estimates of genetic correlations of 18 months wool and pre-mating live mass traits with average reproduction over two to five lambing opportunities, as well as between pre-mating live mass and…
Six male and 24 female Cherry Valley Pekin ducklings were randomly allocated to each of 12 pens to test the effects of quantitative feed restriction during the rearing period on the subsequent reproductive performance. The three treatments were 50% of…
The efficiency of meat production with regard to kilogram of lamb weaned per kilogram metabolic mass of ewes at mating of six different Fl crossbred populations, viz. Finnish Landrace x Merino (FL x M), Border Leicester x Merino (BL x…
The object of this study was to estimate heritabilities and genetic correlations for reproductive traits in a composite multibreed beef cattle herd using multitrait analysis. A REML procedure fitting a multitrait animal model was used to analyse data. Heritabilities and…
The object of this study was to estimate heritabilities and sire breeding values for stayability and reproductive traits in a composite multibreed beef cattle herd using a threshold model. A GFCAT set of programmes was used to analyse reproductive data…
Seventy-seven mature Tswana goats were used to investigate the effect of supplementation on reproduction of wet season kidding animals. Treatments groups with similar weights were: Unsupplemented Control (UC), Continuous Supplementation (CS), Before Rain Supplementation (BRS) and After Rain Supplementation (ARS)…
Data used for this study were collected on the Carnarvon Afrino flock from 1986 to 1998, and include data records on several subjectively assessed traits, body weight and fleece traits of 3291 animals, the progeny of 127 sires and 772…
This study details the production performance of ewes and lambs that originated from a terminal crossbreeding experiment that involved five Merino type dam lines and two terminal crossbreeding sire lines from 1999 to 2002. Ewe lines were SA Mutton Merino…
The production performance of ewes was assessed in a terminal crossbreeding experiment involving five Merino and Merino-type dam lines and two terminal crossbreeding sire breeds. Dam lines were SA Mutton Merino (SAMM), SAMM rams crossed to Merino ewes (SAMM cross),…
Carcass data of 114 19-month-old Merino sheep descended from two lines that were divergently selected for maternal multiple rearing ability (H and L lines, respectively) were used. In study A only ram progeny of the same age were slaughtered, while…
The effect of early mating on the production and reproductive ability of Nguni heifers was investigated. One group (MN group) of heifers (n = 15) was stall-fed from weaning and mated at approximately 13 months of age. The second group…
A general method is developed for the evaluation of herd efficiency in terms of efficiencies for growth and reproduction. Almost the only requisite knowledge for the application of this method is the value of the allometric slope between the cost…
A primary objective of commercial pig production is lean meat yield in order to satisfy consumer needs. The majority of the commercial pig breeds in South Africa have been selected for high lean growth potential and reduced backfat thickness. There…
Results are presented of a study of a smallholder goat production system in the Boane district, southern Mozambique. Goat keepers (n = 65) were selected and their goats (Landim breed) (n = 770) were recorded and monitored over two years…
