Ruminal degradation of crude protein from feedstuffs was determined in steers that were fed diets based on either maize (whole, meal or flakes) or on by-products of the milling industry. In addition to the in sacco degradation study, fractional outflow…
Optimal levels of crude (CP) and undegraded (UDP) dietary protein were studied in feeding systems based on whole maize fed free-choice and on complete mixed diets composed from by-products of the milling industry. On the whole maize free-choice system, animal…
Twelve steers fistulated in the rumen and duodenum were allocated to one of three diets and fed 80 g DM/kg W0.75/d. The diets consisted of about 80% maize meal, 11% cottonseed hulls and either 1.44% urea (Treatment A), 0.96% urea…
This experiment was conducted to determine whether selection for fleece weight is accompanied by changes in the efficiency of nitrogen utilization, using Angora and Boer goats as models of animals bred for fleece or meat production respectively. A diet, containing…
It has been proposed that the abortions, cold-stress fatalities, and slow growth rates typical of the South African type of Angora goat can be explained by congenital adrenal hypofunction incident to genetic selection for hair production. The aim of this…
The performance of 92 Holstein-Friesian bulls, which were accepted for progeny testing under the South African National Dairy Animal Performance and Progeny Testing Scheme during 1982, 1983 and 1984, was compared. Bulls which were locally bred for more than one…
Samples of 150 different cowpea cultivars, used in the breeding trials of the Summer Grain Institute at Potchefstroom, were analysed and found to have an average crude protein content of 28.4 ± 1.8% (range 24.5 to 33.9%). From these samples,…
The influence of sire breed and breed genotype of dam on birth and weaning mass in calves of Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as F1 and two- and three-breed rotational crosses between Afrikaner, Hereford and Simmentaler were…
The influence of sire breed and breed genotype of dam on calving interval (CI) and cow productivity (CP) in Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as in Fl, and two- and three breed rotational crosses between Afrikaner, Hereford…
The experiment was carried out to compare fababean with lupin crop residues for summer grazing by young Merino wethers. The crude protein (CP) and dry matter (DM) degradability as well as chemical composition of fababean and lupin seed and stalks…
Breeding values of production traits, relative to a genetic control flock, were estimated for 40 registered Merino studs. Breeding values, expressed as a percentage deviation from the control flock, varied from -16.7 to 31.2 for body mass, -6.4 to 28.1…
The nutritional value of Geotrichum candidum, produced on an acid effluent from Sasol, was determined. Analysis of G. candidum revealed (on an air-dry basis) a crude protein content of 53.4% and a true protein content of 38.8% with a favourable…
The aim of the study was to examine the effects of the substitution of lucerne hay by untreated, urea-enriched and urea-ammoniated wheat straw on (i) dry matter intake (DMl), digestibility and nitrogen balance, (ii) in situ degradability, (iii) rate of…
The experiments reported in this series were designed to investigate the metabolism of lysine, leucine and methionine in lambs fed roughage diets supplemented with various levels of protein. and to compare these amino acids as tracers of whole-body protein metabolism…
The effect of protein supplementation of a wheat straw diet on the metabolism of lysine, leucine, methionine and urea, and on whole-body protein turnover rate was investigated in lambs. The metabolism of lysine and leucine is reported elsewhere (Cronje et…
The aim of this experiment was to distinguish between the effects of dietary roughage: concentrate ratio and rumen ammonia concentration on rumen in situ degradation in sheep. Three diets with roughage: concentrate ratios of (Eragrostiscurvula hay:maize) 75:25, 50:50 or 25:75…
Dormer (n = 166) and SA Mutton Merino (n = 147) ewes were observed continuously during lambing in the autumn lambing seasons of 1989-1991. Although SA Mutton Merino ewes had larger (P ≤0.01) litters at birth than Dormers (2.08 vs…
