The aims of this work were first to evaluate nutritional requirements of early weaned kits (23 days of age), more especially fibre (experiment 1) and protein (experiment 2) needs. In experiment 1, 276 early weaned rabbits were offered from 23 to 50 days of age one of the three experimental diets containing increasing acid-detergent fibre level (160, 190 or 220 g/kg). Fibre was substituted by starch and fat to obtain three isoenergetic diets. In experiment 2, 306 early weaned rabbits were offered from 23 to 50 days of age one of the three experimental diets containing increasing crude protein (CP) level (150, 180 or 210 g/kg). Protein was substituted by starch and fat to obtain three isoenergetic diets. These studies revealed no effect of the dietary fibre level and the dietary CP level on health status. But from 23 to 36 days of age rabbits given diets containing a fibre level over 190 g/kg or a CP level under 180 g/kg showed the lowest growth rate as compared with other respective treatments. Secondly, this research aimed to evaluate the interaction between age at weaning (23 days or 35 days of age) and food (RD and RY diets) on digestive health and performances of young rabbits (experiment 3). RD diet was formulated to contain (per kg) 170 g starch, 160 g fibre and 180 g CP (according to the nutritional requirements of does) and RY diet was formulated to reach 110 g starch, 160 g fibre and 210 g CP (according to the results of experiments 1 and 2). 39 litters of nine pups per litter were assigned at 18 days of age to one of four experimental groups in a 2×2 factorial design: RD23 (no.=84 rabbits), RY23 (no. =85 rabbits), RD35 (no. =86 rabbits) and RY35 (no. =74 rabbits). Food intake and live weight were not influenced by feeding strategy. Between 23 and 35 days of age, mortality was higher in RY than in RD group (20·4 v. 6·8% respectively; P<0·05). During this period growth rate was proportionately 0·584 higher in conventionally weaned than in early weaned rabbits ( P<0·001). After 35 days of age, food intake and growth rate were proportionately 0·104 and 0·097 higher respectively in conventionally than in early weaned rabbits ( P<0·05). Consequently, live weight was higher in conventionally weaned rabbits at both 35 and 53 days of age (proportionately +0·113 and +0·267 respectively; P<0·001). Mortality rate between 23 and 35 days was 21 points higher ( P<0·001) in early weaned than in conventionally weaned pups and 43 points higher ( P<0·001) from 35 to 53 days of age. These data suggest that the removal of milk feeding by early weaning leads to detrimental effects on health and growth of the young, which were not compensated by a diet meeting better their nutritional needs.

Twenty-five New Zealand White × Californian lactating doe rabbits were used to study the effect of different dietary fibre concentrations on the amino acid contribution of soft faeces to the total amino acid intake. Five isoenergetic diets containing 312, 334, 360, 384, and 412 g/kg neutral-detergent fibre (DM basis) were formulated. All diets were designed to maintain the same amino acid pattern. Soft faeces production showed a trend to increase (P = 0·07) as dietary fibre increased. The content of isoleucine (P < 0·01), glutamic acid, leucine and alanine (P < 0·05) in soft faeces decreased as the dietary fibre increased. A trend to decrease with the increase of dietary fibre was also observed for aspartic acid (P = 0·06), lysine (P = 0·07), methionine and valine (P = 0·1). As a consequence, the soft faeces contribution to the total intake of individual amino acids did not vary with the type of diet. The average contribution of soft faeces to the total amino acid intake for the most limiting amino acids of lactating doe rabbits under practical conditions, methionine, threonine and lysine, were 0·17 , 0·21 and 0·18 g/g, respectively.

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.

One hundred and twenty crossbred gilts and sows were used in an experiment with three differently composed pregnancy diets in order to study the effects on performance during three reproduction cycles. Treatments during pregnancy were: (1) a standard diet; (2) 500 g sugar-beet pulp per kg diet; (3) 500 g mixture of green grass-meal, wheat bran and oat hulls per kg diet. Sows were given similar levels of estimated daily net energy (NE). All three groups were given the same standard lactation diet semi-ad libitum in two daily meals. Recordings were made of food intake during pregnancy and lactation, body weight of sows at mating, farrowing and weaning, days until first mating, litter size, and mean piglet weight at birth and weaning. Pregnancy food intake (kg) was highest in diet 3 and lowest in diet 1 (P < 0·001). Food intake was lower for sows given diet 2 than for sows given diets 1 and 3, when measured in NEfor pigs (P < 0·001). Food intake during lactation was higher for sows given diet 2, than for sows in the two other diet groups (P < 0·01). Results were consistent during all three experimental rounds. Mean body weight of sows was the same for all diet groups both at mating, farrowing and weaning. Weight gain during pregnancy and weight loss at farrowing was significantly higher in groups 2 and 3 than in group 1 (P < 0·001). Litter size was not affected by the different pregnancy diets, neither total number live born nor weaned. Both mean piglet weight and total mean litter weight at birth were negatively influenced by diet 2 (P < 0·001) and (P < 0·05) respectively. This indicates that a diet with a high content of soluble dietary fibre and a large capacity to induce satiety may have a negative effect on piglet weight at birth. At weaning, however, the mean weights of piglets were the same for the three diet groups. It was concluded, that it is possible to feed pregnant sows very differently composed diets without detrimental effects on performance.

The effects on the production of indoles of dietary fibre, lactose and antibiotic were examined in a factorial design using 16 crossbred pigs (eight boars and eight gilts) from 40 to 90 kg live weight. The control diet was based on wheat and soya-bean meal which was partially replaced either by sugar-beet pulp (400 mg/g) or lactose (25 mg/g) or both. All diets were offered with or without the antibiotic tylosin phosphate (200 mg/kg diet). Animals were penned individually and the diet restricted to provide 1·3 M] digestible energy per kg M0·75. All faeces were collected for two 4-day periods at about 60 and 75 kg live weight. Animals were slaughtered on completion of the experiment and subcutaneous fat was sampled. Faeces and carcass fat were analysed for skatole and indole. There were no significant effects of treatments on growth rate but killing-out proportion was reduced (P < 0·05) on fibre or lactose diets with an additive effect (P < 0·001) of the combined ingredients. Dietary fibre significantly increased the daily elimination of skatole and indole and the concentration of indole in faeces but because of greater faecal bulk on the fibre diet the concentration of skatole in faecal dry matter was higher (P < 0·05) on the control diet. Dietary lactose had no effect on indole in faeces but significantly reduced the concentration and daily output of skatole. Levels of both skatole and indole in faeces tended to be reduced with dietary antibiotic which had a significant interaction with the fibre treatment on indole levels. The concentrations of skatole or indole in subcutaneous fat were neither affected by dietary treatment nor significantly correlated with concentrations or outputs in faeces.

During two experimental periods, eight non-lactating, rumen fistulated Simmental cows were given 2 kg/day of a cereal based concentrate and fescue hay ad libitum. The hay differed in neutral-detergent fibre concentration (LNDF: low; HNDF: high) and physical form (L: long; C: coarsely chopped). The rumen degradability of the dietary ingredients and of an extracted soya-bean meal was studied using the polyester-bag method.

The estimated effective rumen degradability <DG) of dry matter (DM) was significantly higher for LNDF than for HNDF hay (0·490 v. 0·401; P < 0·01). The DM DG of the extracted soya-bean meal and the dietary concentrate were higher when incubated with LNDF than with HNDF diets (0·630 v. 0·581, P < 0·05, and 0·541 v. 0·514, respectively).

Chopping the hay significantly increased the daily DM intake for HNDF diets (from 9·9 to 11·6 kg; P < 0·05), while no statistical differences were found between the other diets (10·2 and 9·6 kg, respectively for L-LNDF and C-LNDF diets). Cows given HNDF hay drank less water (42·4 v. 51·7 I/day) and total water consumption, expressed per unit of DM intake, was lower for the HNDF diets (4·1 v. 5·3 I/kg DM; P < 0·01).

Dietary treatments did not affect the estimated rumen turn-over rate of hay (0·027 per h on average, k1), hay post-rumen turn-over rate (0·069 per h on average, k2) or the estimated rumen liquid turn-over rate (0·100 per h on average, kj. The calculated outflow from the rumen was lower for the HNDF diets (159·4 v. 198·7 I/day). The daily amount of estimated saliva secreted did not differ between treatments, although saliva expressed per kg DM intake was significantly lower for the HNDF diets (10·8 v. 14·8 I/kg DM; P < 0·05).

The HNDF diets gave a lower post-feeding rumen pH (6·29 v. 6·58; P < 0·01), a higher concentration of n-butyrate (9·58 v. 8·32 mmol/l; P < 0·05) and a lower concentration of ammonia nitrogen (NH3-N) (80·5 v. 128·5 mg/l; P < 0·05). Of the C4 and C5 iso-acids, the rumen liquid from cows given HNDF diets had significantly lower concentrations of isobutyrate, isovalerate and n-valerate (P < 0·01). Hay physical form did not affect rumen pH, NH3-N and volatile fatty acid concentrations.