Properties of the non-carcass parts in combination with empty body and half carcass weight (EBW and CCW; kg) were used to generate equations for predicting empty body chemical composition. Therefore, chemical composition of the non-carcass parts and weight of the depot fatty tissues were determined on 18 Belgian Blue double-muscled fattening bulls. Very high coefficients of determination (R2) were found between the empty body composition and on the one hand the non-carcass parts composition and on the other hand the weight of the fatty tissues. Fat in the empty body was most difficult to predict. The very high coefficients of determination are partly caused by the large variation in slaughter weight (309 to 723 kg). Therefore equations to estimate proportional composition of the empty body are discussed. Although R2 values are strongly reduced, residual standard deviations remain very low and the precision of prediction is good. The proportion of protein is most difficult to predict, as it shows a very small variation. Estimations based on composition of the non-carcass parts are mostly a little more precise than the estimates based on weight of the fatty tissues but as the latter are much easier to determine, these equations will be more appropriate for practical use. Similarly the little improvement of the estimation based on EBW instead of CCW, cannot account for the extra costs and time to determine EBW. The results of the homogenizations have proven that there is very little variation in composition, despite the large range in slaughter weight. As the Belgian Blue double-muscled animals are very deviant from other breeds, the equations found in this study can only be applied for this breed type.

In west Asia, it is traditional for sheep to gain body condition when low-cost native pastures are available and to mobilize reserves thus built up at other times. With diminishing shares of native pasture, crop by-products and food grains are increasing in sheep diets, and facilitate feeding for constant body condition.

In a 2 × 2 × 2 factorial experiment, 48 Awassi ewes were individually fed indoors, nursed single lambs for 42 days, and were hand-milked from day 29 after lambing. Dietary treatments were imposed at different times: level of feeding (i) in the last 24 days of pregnancy (Lconstv. Lmob), (ii) in days 18 to 60 after lambing (Lconstv. Lmob), and (iii) level of fibre in days 60 to 102 after lambing (Fhigh v. Flow). Rations Pconst, Lconst, Flow and Fhigh were calculated to maintain body condition. Fhigh provided the calculated maximum ingestible quantity of barley straw and Flow provided 0·08 kg barley straw per kg diet. Live weights (M) of ewes and lambs, milk yield and milk quality were recorded.

With Pconst, and Pmob (0·51 and 0·33 MJ metabolizable energy (ME) per kg M0.75 per day), M gains were 140 and 23 g/day (P < 0·001). Lamb birth mass and subsequent maternal milk yield were not affected. With Lconst and Lmob (0·81 and 0·61 MJ ME per kg M0.75 per day), M changes were -28 and -70 g/day (P < 0·001) and milk yields (calculated in part from lamb growth) were 1042 and 892 g/day (P < 0·01). Fhigh and Flow (385 and 170 g acid-detergent fibre per kg dry matter) were compared in a two-period change-over design experiment. Milk yields were similar (414 and 427 g/day), milk fat concentrations were 64·8 and 72·9 g/kg (P < 0·001) and milk fat yields were 26·5 and 31·1 g/day (P < 0·001) but solids-not-fat and protein yields were not affected.

There were benefits and costs in manipulating body reserves in Awassi sheep. M at lambing affects milk yield and body condition around mating is known to improve lambing rate. The existence of body reserves also allows body condition to be lost in late pregnancy and early lactation without affecting health or apparent welfare, which simplifies management of pregnant ewes, permits feeding of milk-fat-increasing high-fibre diets but the ME to maintain increased body reserves must not be ignored.

This experiment studied the effects of body condition, long- and short-term levels of nutrition and trypanosomosis infection on the productivity of N’Dama cows using a 2 x 2 × 2 factorial cross-over design. Pre-partum, 23 cows received supplements for 6 months (H), the other group of 20 for 2 months (L). Both groups grazed native pastures. Two days post partum, half the cows from each group were placed on a basal (B) or supplemented (S) plane of nutrition. The diet of concentrate, groundnut hay and andropogon hay was the same, only the quantities differed. Four weeks post partum half the animals in each group were inoculated with T. congolense organisms (I), the others acted as controls (C). The trial continued for a further 6 weeks.

Pre-partum nutrition (H, L had no effect on dry-matter intake (DMI) but pre-partum feeding (H) improved post-partum productivity, evident by higher dam live weights (P < 0·05), body condition (P < 0·001), calf birth weight (P < 0·05) and calf live-weight gain (P < 0·01). Post-partum nutrition had no effect on productivity. Trypanosomosis infection caused a reduction (P < 0·05) in total DMI. The decline in groundnut hay and concentrate intake was proportionally (P < 0·001) greater in the S-I group than in the B-I group. A low plane of nutrition pre-partum depressed milk yield but increased fat concentration (P < 0·05). Infection significantly reduced milk offtake (P < 0·05). The reduction in milk offtake (P < 0·01) and calf live weight (P < 0·05) were proportionally larger in the B-I than in the S-I group. Infection caused a decline in milk protein concentration (P < 0·05) and protein yield (P < 0·01) which was independent of dietary effects. Infection reduced (P < 0·01) the packed-cell volume but there were no interactions with diet. None of the cows was pregnant 150 days post partum but seven were cycling, 3(5) in the H-S-I group, 2(7) in the H-B-I group, 1(5) in the L-B-I group and 1(5) in the L-S-C group. These results suggest that S-I cows attempted to maintain milk yield at the expense of live weight whereas the B-I cows had insufficient live-weight reserves that could be mobilized. This suggests the nutritional balance and changes in weight at the time of infection might be more important than historical planes of nutrition.