Forty-five ewes (29 Romanov X Dorper, 9 Karakul, and 7 Dorper) were divided into four groups, synchronized using progestagen sponges and superovulated with 1000 IU pregnant mare serum gonadotrophin. Sponges were withdrawn on days 13, 14, 15 and 16 (in…
Fat provides essential fatty acids and a concentrated source of energy for dairy cows. The energetic efficiency of milk production is therefore also improved. Of the numerous fat sources that are available, oilseeds, especially cottonseed, probably offer the best opportunity…
Mean daily milk yield for 478 Holstein-Friesian cows from two herds, recorded between 1984-1985, and for 218 Jersey cows from two herds, recorded between 1984-1985, were used to estimate lactation curve parameters for Wood's gamma function: Yn = A nbe-cn.Yn…
It is suspected that feeding large amounts of whole cottonseed and cottonseed meal to dairy cows can cause gossypol intoxication. It has also been shown that male antifertility is probably the first physiological effect of free gossypol. The objective of…
Grain sorghum, forage sorghum, sunflower and maize were ensiled on laboratory scale. Sunflowers, harvested at the milky seed stage of maturity, resulted in silage containing only 13,54% dry matter (DM). Maize, grain sorghum and forage sorghum silages, contained approximately 30%…
Microwave-processed full-fat soy beans for use in broiler diets. An experimental microwave oven, delivering microwaves of 1,3 kW (frequency of 2450 MHz), was used to process air-dry (9,13% moisture) and moistened (23,08% moisture) full-fat soy beans. The processed beans were…
Supplementation of early and mid-season Italian ryegrass (Lolium mu/tiflorum cv. Midmar) with maize meal, maize meal with NaHC03 buffer, or maize meal plus combinations of slowly degradable protein was studied. Supplements were administered via a rumen fistula. The effect on…
The effect of feeding level on puberty development in Nguni, Bonsmara and Drakensberger heifers: The growing interest in the Nguni and the need for reliable data on the breed led firstly to an investigation of puberty development in Nguni, Bonsmara…
Supplementation of untreated, urea-supplemented or urea-ammoniated wheat-straw diets with sources of readily fermentable energy (maize-meal; 0 and 20% of the total diet) and rumen-undegradable protein (fish-meal; 0 and 5% of the total diet) was investigated in a 3x2x2 factorial experiment,…
Efficiency or early selection or Merino rams on a selection index. Production traits of 196 unselected young Merino rams were measured at two consecutive shearings with six months' wool growth, at the age of 12 and 18 months. The correlation…
Mechanisms that have been proposed to account for (i) premature regression or (ii) subnormal secretory activity of corpora lutea (CL) in cows or in ewes are reviewed. Processes which occur prior to, at the time of, or following, ovulation are…
Seventy-eight pigs (40 boars and 38 castrates) were used in a growth trial to study the effect of high oil class FH sunflower seed on the long chain fatty acid composition of backfat in baconer pigs. Three diets were formulated…
Forty-eight Dorper lambs, comprising 24 ram and 24 ewe lambs, were divided into four groups of six ram and six ewe lambs each and were allocated to one of the following feeding levels: ad libitum, 80%, 65% or 50% of…
The experiment was conducted (a) to determine the relationship between in vitro digestible organic matter (IVDOM) and in vivo digestible organic matter (DOM); (b) to quantify the monthly variation in chemical composition and digestibility of medic pasture; and (c) to…
Numerous studies have shown that in the acyclic ewe, the fIrst corpus luteum (CL) after administering gonadotropin releasing hormone (GnRH) will lead to inadequate progesterone (P4) concentrations or will be short-lived. An attempt was made to promote the function…
No difference in protein quality was noted between three species of earthworms, as evaluated by net protein utilization and relative nutritive values in growing chickens. Similar growth responses per g nitrogen intake were obtained for the earthworm meals, a broiler…
Sixty Dorper lambs, comprising 30 ewe and 30 ram lambs, were divided into six groups of five ewe and five ram lambs each. Each group received, on an ad libitum basis, one of six diets consisting of a concentrate: roughage…
No experimental evidence exists on the biological advantages of frequent or maximum reproduction compared to lower or optimal levels of reproduction. Twenty unrelated rats, divided into two groups, were thus used in the biological comparison between optimum and maximum reproduction…
Selection for production and reproduction in South African Merino sheep is always combined with selection based on visual appraisal and will, in all probability, remain so for many years to come. Heritabilities for acceptability were estimated using a threshold model…
Imbrasia belina is utilised as a food item by certain ethnic groups of southern Africa, but little is known of the genetic structure of this resource. The aims of this study were to determine whether the limited flight ability of…
