An experiment was conducted to measure the response of goat kids to supplementary feeding of their dams with protected fat (calcium soap of fatty acids). At birth, 22 single male goat kids were distributed in two groups according to the dams’ diet supplemented with 0 (dam control diet, DCD) or 100 (dam protected fat, DPF) g/day of protected fat through lactation. Higher energy intake of dams given protected fat caused higher fat content of their milk (P < 0·01) and the fatty acid profile was affected with a reduction of lauric acid (P < 0.01) and myristic acid (P < 0.01) and an increase in palmitic acid (P < 0.01). Goat kids were suckled by their dams from birth until the end of the experiment and had access to a creep food from 7 days of age. Kids were slaughtered at 45 days of age. There was no significant response (P > 0Ό5) in terms of kid mean live-weight gain, being 172 g (DPF) compared with 148 g (DCD). Fatty acid composition of the perirenal fat showed some differences between groups. Fat composition of group DPF was significantly higher in palmitoleic, oleic and linoleic acid content. In addition, myristic, palmitic and stearic acid had lower values. Fat of goat kids of the DPF group was more unsaturated (43·3 g per 100 g) than fat from animals of the DCD group (32·5 g per 100 g). In the DPF group, oleic acid comprised most of the unsaturated fatty acid due to its important increase compared with fat composition of the DCD group. In conclusion, fatty acid composition of fat depot in goat kids can he modified by feeding of the dams through lactation, which could be useful for possible changes according to market demand.

The Maasai of Kenya are typical of many pastoral communities in that they rely on milk as a major part of their diet. Milk production in three herds of Maasai cattle was studied from 1991 to 1996. Weekly measurements of milk extracted for human consumption were used to estimate lactation length, total offtake and mean daily production. Calf live-weight data were used to estimate total milk yield. Least-mean squares regression and analysis of variance tests were adopted to assess the effect of a number of variables on milk production parameters.

Data from a total of 650 lactations and 383 calvings were collected. Mean daily offtake was 891 ml. The length of lactation of frequently milked cows was 372 (s.e. 7·96) days. Total lactation offtake was estimated at 305 I. Herd, parity level and year of calving differences were observed. Multiple regression analyses indicated that some of the variation in daily offtake could be explained by stage of lactation, season of milking, herd, parity and year of calving. An average total yield of 2·73 I/day was estimated for the first 90 days of lactation. Of this, approximately 0·4 was used for human consumption. Overall, seasonality was seen as the major variable influencing production.

A 28-day experiment with 12 9-month-old cattle (275 kg initial weight, M1), used a 2 × 2 arrangement of treatments to compare the effect of doubling the ad-libitum quantity of long barley straw offered daily (25 or 50 g dry matter (DM) per kg M1) and sex/genotype (Limousin × Friesian steers or Friesian heifers) on intake and selection. All animals received a protein concentrate at 20 g DM per kg M10·75 per day. Prior to the experiment the cattle had grazed for 6 months and were given no pre-experimental change-over period. On day 1 animals were weighed (M1), allocated to treatment and penned individually. Animals were weighed on day 28 (M2). Doubling the amount offered did not affect straw intake (g DM per kg M3 per day; M3 = mean of M1 and M2) during days 22 to 28 (steers: 17·9, 17·2; heifers 14·3, 13·3; s.e. 0·50) but increased the proportion (g DM per kg DM offered) refused (steers: 258, 635; heifers: 412, 721; s.e. 22). During days 22 to 28, at each level of offer (25, 50), refused straw contained (g DM per kg DM) less leaf-plus-sheath than offered straw (25 g steers: 251, 430, s.e. 16·7; 50 g steers: 393, 450, s.e. 19·7; 25 g heifers: 304, 420, s.e. 7·2; 50 g heifers: 405, 446, s.e. 9·6). The sex/genotype effect on intake was attributed to differences in growth potential. Straw intakes increased significantly over the first 14 days, but there were no differences between days 15 to 21 and days 22 to 28. It is concluded that an excess-feeding strategy, involving a doubling of the ad libitum amount of barley straw offered did not result in growing cattle consuming more straw, in contrast to published results with sheep and goats. However, the cattle did show a limited ability to selectively consume leaf-plus-sheath in preference to stem but the improvement in diet digestible organic content (estimated in vitro) was presumably insufficient to stimulate intake.

The disappearance of neutral-detergent fibre (NDF) from six fibrous foods (lucerne hay, NaOH-treated barley straw, olive leaves, paprika meal, soya-bean hulls and sunflower hulls) when incubated in the rumen of sheep in nylon bags was investigated. Source of fibre, time of incubation and its interaction had a significant (P < 0·01) effect on NDF degradation. Stepwise regression analysis showed that the best single predictor for NDF degradation rate was the hemicellulose fraction of NDF (HEMndf). The variables selected to predict potential degradability and degradability of NDF at 72 h were the proportions of acid-detergent lignin in NDF (ADLndf, first step) and of acid-detergent cutin in ADL (ADCadl, second step). For NDF degradability at 12 h, the variables selected were the proportions of HEMndf, ADLndf and ADCadl, in the first, second and third step, respectively. The results showed that ADC is an important component to understand NDF degradability at both 12 and 72 h.

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.