Rumen fermentation was studied during three years in lactating Dorper and Merino ewes, supplemented daily with crude protein and/or energy via rumen fistulae on veld. Herbage, collected with oesophageally fistulated wethers, and maize meal were incubated in sacco in the…
Kikuyu pasture (Pennisetum clandestinum) was evaluated as forage for milk production during the 1985/86 and 1986/87 grazing seasons at the Bathurst Research Station in the seaboard area of the Eastern Cape. The effect of different rotational grazing cycle lengths on…
A study was conducted to estimate the response to selection on BLUP of breeding values for mature body weight (BW), clean fleece weight (CFW) and mean fibre diameter (MFD) in a commercial Merino stud with a high culling rate on…
The relationship between pre- and post-weaning performance of lambs on Italian ryegrass was investigated by grazing lambs at different stocking rates. A positive correlation was found between both the pre-weaning stocking rate (P = 0.008) and weaning mass (P =…
The reproductive performance of cows with post parturient metritis treated systemically with long-acting oxytetracycline was compared with normal herd mates in four South African dairy herds. The incidence of metritis for all calvings in these herds was 7.5% (of 1838…
To determine whether suckling of calves late at night would prolong lactation anoestrus, 51 Hereford-type cows (21 – 29 days postpartum) were divided into three treatment groups. In treatments 1 (night suckling) and 2 (day suckling) cows suckled their calves…
Three diets were formulated to contain 16% crude protein (CP), 12.8 MJ/kg digestible energy (DE) and 0.9% lysine on an air-dry basis. The diets either contained 8.3% fishmeal, 20% faba beans plus 7.9% soybean oilcake meal (SBOK) or 20% low…
Productivity of Simmentaler heifers, first mated at 14 months of age (2 M) compared to the traditional system of mating at 26 months of age (3 M), was investigated under extensive farming conditions. Both first calving (60.8 vs. 79.5%) and…
The effect of migration on inbreeding is modelled for small populations with immigrants from a large unrelated population. Different migration rates and numbers for the two sexes are assumed, and a general recursion equation for inbreeding progress derived, which can…
In conservation and breeding, large populations are important for evolutionary viability and selection progress. On the other hand, practical and economic reasons may exist for population subdivision. These populations (islands) may be tied together to form effectively a single population…
Twenty sheep, ranging in body mass from 25 to 62 kg, were slaughtered to compare two methods of estimating the chemical composition of the carcass. One half of each carcass was ground in a carcass grinder equipped with a 6…
The effect of different shelters, that is, a shade structure (3.5 m high) in a dry lot and a tie-stall barn in comparison to a dry lot with no protection against climatic conditions (rain and wind), on the milk pro¬duction…
The influence of two scenarios of mortality rates (assumed average and observed) on total herd efficiency of the four main breed types in South Africa (Sanga/Zebu, composite, British and European), as well as all the individual breeds participating in the…
The influence of replacement rate (R), price (c/kg carcass weight) and two production systems on total herd efficiency was investigated. R was assumed to be either 15% (minimum), 19% (point in between) or 23% (maximum). Percentage differences (minimum, point in…
A study was undertaken to compare the effectiveness of three different selection strategies in increasing weaning weight of a Dorper flock under natural conditions. Data were analysed by mixed model procedures. Direct selection for weaning weight under natural conditions proved…
Data, consisting of 4235 lamb records, obtained from the Foundation Afrino Sheep Stud at the Carnarvon Experimental Station, were used to investigate factors influencing birth weight, weaning weight, monthly body weight from five to 12 months, body weight at 18…
Water intake, efficiency and consumption of 30 growing individually fed Blackhead Persian, Dorper and South African Mutton Merino (Mutton Merino) ewe lambs were investigated. Average daily water intakes were 2.2, 4.6 and 5.4 litre for the Blackhead Persian, Dorper and…
Four laying strains were evaluated with regard to henday egg production, egg mass, feed conversion, mortality, Haugh units, shell thickness and percentage soiled, cracked and broken eggs produced under a battery, floor house and free-range system. This was done to…
Nitrogen (N) retention and wool growth rate (WGR) responses to various amino acids and derivatives as well as protein sources were determined with six ruminally and six abomasally fistulated Merino wethers in two balanced cross-over design experiments. The six treatments…
In each of three consecutive years (1987/88 to 1989/90), 108 weaner steers (average live mass = 192.5 and standard deviation = 1.9 kg) were divided into three groups of 36 steers and fed to achieve growth rates of 0, 0.3…
