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A study was conducted to investigate changes in the development of the gastrointestinal tract (GIT) in relation to body growth of growing ostriches. There was an 11-fold increase (P < 0.001) in body weight between 3 and 72 days of age. The relative (to body weight) weight of the proventriculus/gizzard, caeca and colon also increased (P < 0.001) with age. The relative weight of the small intestine peaked at 41 days of age and then tended to decline (P < 0.05) subsequently. The relative weight of the pancreas peaked at 27 days of age and remained fairly stable thereafter. The activities of chymotrypsin and lipase declined (P < 0.001) with age between 3 and 72 days. At 3 days of age, the protein content of the duodenal mucosal homogenate was higher (P < 0.001) than that of the jejunum or ileum, but at all subsequent periods the jejunal protein content was the highest. The protein content of the intestinal brush-border membrane was higher (P < 0.001) at the jejunum than at the duodenum or ileum. The specific activity of maltase declined (P < 0.001) with age in all three regions, most especially between 3 and 27 days of age. The activity of alkaline phosphatase (AP) at 41 and 55 days of age was higher (P < 0.001) in the duodenum than in the jejunum or ileum. The activity of AP fluctuated with age in the duodenum but there was a more defined decline (P < 0.001) with age in the jejunum and ileum. The relative protein content of the liver increased (P < 0.001) with age, with two peaks at 27 and 55 days of age. Arginase activity was not detected in the liver of 3-day old chicks and was not significantly affected by age between 27 and 72 days of age. The pattern of development observed is similar to that in growing poultry. There is, however, a need for evaluation at closer intervals in early life as well as an in-depth assessment of the morphometry of the intestinal mucosa.

The primary selection objective in the South African Mutton Merino is meat production, while wool plays a secondary role. The Merino, on the other hand is selected for wool production. Respectively 20 and 23 of each genetic different type of ewes were used in a 15-week indoor study to quantify the influence of nutrient intake on certain production traits when fed at different levels of their respective requirements during late pregnancy (last 6 weeks) and lactation (first 6 weeks). Results were used to provide production parameters for the two types of ewes and their lambs at different levels of nutrition. Lambing percentage (per ewe lambed) of SA Mutton Merino ewes was 171% compared to 135% for Merino ewes. Live weight gains for meat-wool and wool-type ewes during late pregnancy amounted to 15.9 and 21.9%, with corresponding live weight losses of -8.3 and -1.1% during the first 6 weeks of lactation. Greasy wool production during the last 9 weeks of pregnancy and the first 6 weeks of lactation amounted to 1.57kgewe(-1) (meat-wool type ewes) and 2.84kgewe(-1) (wool-type ewes). Milk production 17 days post partum was 2.33kg/day and 1.84kg/day for the two types of sheep. Lambs of the meat-wool type ewes had a mean birth weight of 4.1kg and an average daily gain (ADG) of 270g/day to 42 days of age. Lambs of the wool-type ewes had a mean birth weight of 4.9kg and a 42-day ADG of 192g/day. There were clear differences in production traits of the two types of Merino sheep, which were in accordance with their genetic differences. The study gave practical production norms for meat-wool and wool-type Merino ewes and their lambs when subjected to different nutritional levels.

The grazing behaviour and diet selection by Dorper sheep, as well as other related aspects (pasture intake, walking habits and trampling) is reviewed. It was clear that Dorper sheep are less-selective grazers, compared to Merino-type breeds. Dorpers utilised shrubs and bushes to a greater extent, but grass to a lesser extent in relation to Merino sheep. The Dorper also utilised a larger number of different plant species than Merinos. Dorpers walked less to select food, or a suitable spot to graze, which consequently led to a shorter grazing time and less separate grazing periods. Dorpers consumed less herbage per metabolic size compared to Merino-type sheep. No uniform pattern in the walking distance of Dorpers was observed when compared to other sheep breeds. The relative trampling factor for Dorper sheep was less than that of evaluated Merino-type sheep. The review revealed a lack on information on the grazing behaviour and diet selection of Dorper sheep under more intensive grazing conditions. There is also a total lack of scientific information on other behaviour aspects of this unique breed.

1. The true metabolisable energy (TME) of canola oilcake and full-fat canola seed was determined for ostriches to broaden our knowledge of canola as a potential protein and energy source for ostriches. 2. Both test materials were diluted with a basal diet, fed to ostriches and TME-values estimated by multiple regression analysis. 3. The TME values for canola oilcake meal and full-fat canola seed for ostriches were respectively 13.76 MJ kg(-1) and 22.5 MJ kg(-1). 4. The TME values obtained for these 2 important protein sources will assist in the more accurate formulation of diets for ostriches.

Increased dietary protein consumption is thought to cause calciuresis, a negative calcium balance and increased bone loss that may result in skeletal deformities and fracture. To explore this hypothesis, 40 approximately 100-day-old meat-type Merino ram lambs were fed, for 6 months, diets with an increasing crude protein (CP) content (114, 142, 171 and 190 g/kg DM) but approximately on an iso-nutrient basis with regard to metabolisable energy, calcium and phosphorus. Increased protein consumption modestly (NS) enhanced calciuresis and resulted in significant (P < or = 0.01) limb skewness. This could not, however, be ascribed to osteopaenic bones, and compared with animals consuming lower protein rations, the bone mineral density (BMD) and vertebral trabecular bone volume of animals fed high protein diets were significantly increased: the BMD of thoracic vertebrae was positively related to the CP intake (r = 0.62; P < or = 0.001). In animals consuming higher protein diets, skeletal radiology and quantitative bone histology revealed no evidence of increased bone turnover as would be expected in animals that are in negative calcium balance. No relationship existed between limb skewness and the growth rate of lambs. However, the ratio of Ca:P in the forelimb (r = -0.98), vertebrae (r = -0.72) and rib (r = -0.42) was found to be inversely correlated with increased protein intake and resulted from an increase in the phosphorus content of bone, while the amount of bone calcium was unaffected. We conclude that qualitative micro-architectural abnormalities, and not mere bone loss, may underlie the skeletal deformities induced by increased protein consumption in sheep.