Ninety of each of New Zealand White (NZW) and Californian (Cal) male weaned rabbits at 5 weeks of age with nearly similar average live weights were used during two periods of the year (mild and hot, each of 9 weeks), in a trial to evaluate their adaptability as meat animals to the subtropical conditions of Egypt. The results showed that NZW surpassed Cal, in most of the traits studied. The increase was significant in final live weight, daily weight gain, final body solids, daily body solids gain, body water concentration (ml per 100 g body solids) and pre-slaughter weight. Meanwhile, Cal significantly surpassed NZW in daily water consumption. The temperature-humidity index (THI) values indicated absence of heat stress in the first period and exposure to moderate (but very close to severe) heat stress in the second. The hot conditions induced significant decline in final live weight, daily weight gain, food intake, final body solids, daily body solids gain, plasma tri-iodothyronine (T3) hormone, total proteins, albumin, globulin, total lipids, glucose, electrolytes (Na, K, Ca, Mg and P), pre-slaughter weight and kidneys with fat weight. In contrast, the hot conditions were accompanied by significant increases in water intake, body water concentration, plasma urea-N, creatinine and physiological body reactions (respiration rate and temperatures of rectum, skin and ear). Drinking water containing high levels of salt (3000 p. p. m. and more) caused significant decreases in final live weight, daily live-weight gain, final body solids, daily body solids gain, plasma T3 hormone, total proteins, albumin, total lipids, glucose, pre-slaughter weight and kidneys with fat weight. At the same time, significant increases occurred in water consumption, body water concentration, plasma urea-N, creatinine, electrolytes (Na, K, Ca and P), respiration rate and rectal and skin temperatures. Estimations of adaptability to the subtropical environment of Egypt and tolerance to drinking saline water under the same conditions were found to be proportionately 0·844 and 0·876 and 0·821 and 0·803, in NZW and Cal, respectively.

The purpose of the study was to investigate the rôle of novel mitochondrial uncoupling proteins UCP2 and UCP3 in the poor efficiency of energy utilization observed in piglets offered a low protein diet. Eight male piglets (Landrace × Large White) from different litters were allocated randomly to one of two groups; a high protein group (HP) was given restricted amounts of a diet containing 270 g/kg of crude protein whereas the low protein group (LP) was offered ad libitum a diet containing 27 g/kg of crude protein. The experimental period extended over 4 weeks, including an initial period of 1 week for adaptation. Live weights were recorded weekly and food residues were weighed daily. During the 2nd and 3rd weeks, faeces were collected for measurement of digestible energy intake. Over the last 2 weeks whole body oxygen consumption was measured by indirect calorimetry before, 1·5 h after and 3·5 h after the start of feeding. The piglets were killed at the end of week 4 and tissue expressions of UCP2 and UCP3 were measured by Northern blot analyses using a partial length pig UCP2 probe that had high homology to both UCP2 and UCP3. The HP group maintained their live weight during the experimental period whereas the live weight of the LP group increased significantly (P < 0·01) but only slightly despite a digestible energy intake that was more than twice that of the HP group (P < 0·01). Whole body oxygen consumption of the LP piglets was about three times that of the HP piglets (P < 0·05), with similar increases 1·5 h after feeding (P < 0·05) in both groups indicating increased thermogenesis. A marked increase in the expression of UCP2 and UCP3 was observed in the skeletal muscle, adipose tissue and spleen of the LP piglets. The results are consistent with a rôle for UCP2 and UCP3 in diet-induced thermogenesis in piglets and specifically in the regulation of efficiency of energy utilization in pigs.

Twenty pregnant Comisana ewes were divided into two groups of 10. One group was allowed to graze a vetch pasture (grass). The second group of animals was housed collectively in a pen and was given hay and concentrates (concentrate). After lambing, all the ewes were allowed to stay with the respective lambs between 18:00 h and 07:00 h of the following day in two different pens. Therefore all the lambs were raised exclusively on maternal milk. The lambs were slaughtered at 38 days of age. Milk and lamb meat (longissimus dorsi muscle) fatty acids were analysed. Ewes on grass produced milk with a lower (P < 0·001) proportion of saturated fatty acids and with a higher proportion of both monounsaturated (P < 0·05) and polyunsaturated fatty acids (P < 0·01) than ewes given concentrates. Trans-vaccenic acid was significantly higher (P < 0·001) in milk from grass-fed animals compared with ewes given concentrates. Linoleic acid (C18: 2 n-6) tended to be higher (P = 0·06) in milk from ewes on concentrates while linolenic acid (C18: 3 n-3) was significantly higher (P < 0·001) in milk from animals grazing pasture. Conjugated linoleic acid (cis-9, trans-11 C18: 2) was almost double in milk from grass-fed ewes compared with animals given concentrates (P < 0·001). Regarding lamb tissue, trans-vaccenic acid (C18: 1 trans-11) was higher (P = 0·01) in the fat from lambs raised by grazing ewes. Linoleic acid (C18: 2 n-6) was at higher concentration (P < 0·001) in the fat from lambs raised by ewes given concentrates. Linolenic acid (C18: 3 n-3) was increased three-fold (P < 0·001) in the fat of lambs from the grass group compared with lambs suckled by ewes given concentrates. The isomer cis-9, trans-11 of conjugated linoleic acid was present at double concentration (P < 0·001) in the fat from animals raised by grazing ewes. Eicosapentaenoic (C20: 5 n-3; EPA) and docosaesaenoic (C22: 6 n-3; DHA) acids were higher (respectively P < 0·001 and P = 0·01) in the intramuscular fat from lambs from the grass group compared with animals from the concentrate group. The n-6/n-3 ratio was lower (P < 0·001) in the meat from lambs raised by grazing ewes. Overall this trial showed that ewe feeding system strongly affects intramuscular fatty acids even in lambs raised exclusively on maternal milk.

Abstract One hundred and twenty multiparous does were synchronized to give birth the same day (initial kindling). The trial lasted until the successive (final) kindling. Immediately following initial kindling, 22 does were selected for comparative slaughter. The remaining does were assigned to three reproductive rhythms and mated 2 (R2), 11 (R11) or 26 (R26) days post partum. Within each rhythm, the does were further divided into two groups with litters weaned at 21 (W21) or 25 (W25) days of age. A total of 54 does were pregnant and were slaughtered soon after final kindling. By increasing the kindling-to-mating interval from 2 to 26 days, total milk production was increased (5590 to 6065 g for R2 and R26, respectively; P < 0·05); voluntary food intake during lactation was not affected (356 g/day on average), but during the dry period was reduced (182 to 169 g/day; P < 0·05) in this way accounting for a decrease during the experimental period on the whole (299 to 249 g/day; P < 0·01). At the final kindling, the number of kits born per litter was lower in does submitted to the R11 than to the R26 rhythm (P < 0·01). By increasing the kindling-to-mating interval, doe body water concentration decreased, while fat and energy increased (P < 0·01) and higher empty body gain was recorded (from −123 to −4, and to +97 g, in R2, R11 and R26 does, respectively; P < 0·001). As a result, body protein, fat and energy balances changed from negative values to approach equilibrium as reproductive rhythm became extensive (energy balance: −0·14, −0·02 and +0·01 of the initial body content in R2, R11 and R26 does, respectively; P < 0·001). At 28 days after kindling, blood leptin concentration was higher (P < 0·01) and IGF-1 lower (P < 0·05) in R26 does. Daily food intake throughout the experiment was lower (P < 0·05) in W21 does due to the longer dry period. Increasing weaning age from 21 to 25 days increased both number of kits born alive per litter (from 7·4 to 9·6; P < 0·05) and doe body water concentration, while body energy tended to decrease (P < 0·1). At 28 days after kindling lower blood leptin concentration was recorded in W21 than W25 does (1·87 v. 2·76 μg/l, P < 0·05).

Five castrated male pigs (100±2 kg mean live weight) fitted with T-shaped ileal cannulae were used to determine ileal digestibility of raw or autoclaved (136°C, 3 min, 2·3 bar) kidney-bean seed meals, which were included (536 g/kg) in the diet as the only protein source. A protein-free and a diet based on hydrolysed casein were used to estimate endogenous protein secretion. Apparent ileal digestibility of dry matter was lower (P < 0·05) for raw compared to autoclaved kidney-bean meal. Apparent and true ileal digestibilities of raw kidney-bean meal were not only lower (P < 0·05) than those of autoclaved kidney beans, but negative or close to zero for N and some amino acids. Ileal N (36·9 g/kg food ingested) and sialic acid (3·5 g/kg food ingested) flows in pigs given the raw kidney-bean-based diet were higher (P < 0·05) than those of pigs given the autoclaved kidney-bean diet (respectively 8·9 and 1·4 g/kg food ingested). Autoclaved kidney beans contained 364 and 143 g/kg of starch and non-starch polysaccharides respectively, the ileal digestibilities of which were 0·79 and 0·26. Among individual non-starch polysaccharide sugars, apparent ileal digestibility values were between 0 (rhamnose) and 0·38 (arabinose). Ileal apparent digestibility of total oligosaccharides in the autoclaved kidney bean diet was 0·52, and total amounts of oligosaccharides digested was 18·6 g/kg food. Among individual short-chain fatty acids in ileal contents, only propionate values were signifi cantly (P < 0·05) different between pigs given raw or autoclaved kidney-bean diets. Lactate concentration in ileal contents was higher (P < 0·05) in pigs given autoclaved compared with raw kidney beans. Ileal digestibility of autoclaved kidney-bean meal in the 10-kg pigs was poorer than that of other raw legume-seed meals such as lupins and chickpeas in other studies. The potential health implications of these results are also discussed.

Abstract A study was designed to determine if pig performance and lysine conversion ratio would be improved by phase feeding a series of diets with either the same, or with reduced overall mean crude protein (lysine) content, compared with providing a single diet throughout the growing-finishing period. Four hundred and forty-eight group-penned pigs (no. = 32 groups) were assigned at random to one of four treatments: single diet (SD: 11·1 g lysine per kg), high lysine (HL: 12·2, 11·6, 11·1, 10·5 and 10·0 g lysine per kg), medium lysine (ML: 11·1, 10·5, 10·0, 9·5 and 8·9 g lysine per kg) and low lysine series of diets (LL: 10·0, 9·5, 8·9, 8·4 and 7·8 g lysine per kg). The mean lysine contents of the treatments were 11·1, 11·1, 10·0 and 8·9 g/kg for SD, HL, ML and LL respectively. There were five 2-week phases from 38·3 kg to slaughter at 97·3 kg live weight. LL pigs had lower carcass average daily gain (709 v. 742 g/day; P < 0·05) and poorer carcass FCR (P < 0·05: 2·95 v. 2·84 kg/kg) than SD pigs. Daily lysine intake was lower for pigs on HL (P < 0·05: 22·5 g/day), ML (P < 0·001: 20·9 g/day) and LL (P < 0·001: 18·2 g/day) compared with SD (23·4 g/day). Live weight lysine conversion ratio was better for HL (P < 0·05: 26·9 g/kg), ML (P < 0·001: 24·5 g/kg) and LL (P < 0·001: 22·6 g/kg) pigs compared with SD pigs (27·6 g/kg), but carcass lysine conversion ratio was only better for pigs on the ML (P < 0·001: 27·9 g/kg) and LL (P < 0·001: 25·7 g/kg) treatments compared with SD (31·6 g/kg). Nitrogen intake was lower for LL pigs than SD pigs (P < 0·001: 3·45 v. 4·03 kg). Estimated nitrogen excretion was lower for ML (P < 0·01: 2·16 kg) and LL (P < 0·001: 1·85 kg) pigs than SD pigs (2·47 kg). Nitrogen deposition rate was lower for pigs on the LL compared with the SD treatment (P < 0·05: 22·3 v. 23·2 g/day). Although phase feeding diets with the same mean lysine content (11·1 g/kg) as a single diet over the growing-finishing period resulted in similar pig performance, reduced overall daily lysine intake and improved lysine conversion ratio, there was no effect on carcass characteristics or carcass lysine conversion ratio. Reducing the overall mean lysine content to either 10·0 or 8·9 g/kg improved lysine conversion ratio and reduced nitrogen excretion. However, reducing the overall mean lysine content of the diet to 8·9 g/kg had a negative effect on pig growth performance.

The aim of the present study was to evaluate the effect of nucleotide supplementation on the oxidative stress induced by a high proportion of dietary polyunsaturated fatty acids ( PUFAs) in pigs. Twenty-four male growing pigs were penned individually and after an adaptation period divided into three groups. All groups received isocaloric daily rations composed of a basal diet supplemented with either: starch (CONT), linseed oil (LIN) and LIN and nucleotides (LIN + NUC). The experimental period lasted 21 days. Oxidative stress was evaluated by measuring the degree of lymphocyte nuclear DNA damage, the urine malondialdehyde ( MDA) excretion rate, erythrocyte glutathione peroxidase concentration and the total anti-oxidant status of plasma. Malondialdehyde concentrations in the blood and MDA urinary excretion rates were higher (P < 0·01) in animals supplemented with LIN and LIN + NUC compared with CONT animals. The degree of DNA damage in the LIN-supplemented animals was also higher (P < 0·01). Compared with the LIN-supplemented animals, nucleotide supplementation reduced (P < 0·01) the degree of DNA damage in lymphocytes to the level of the CONT group. Erythrocyte glutathione peroxidase concentration and plasma total anti-oxidant status were similar across treatments. The results of this experiment indicate that nucleotide supplementation effectively eliminates the genotoxic effects of high PUFA intakes on blood lymphocytes and demonstrates new evidence for the immunonutritive effect of nucleotides.

Major nutrient and amino acid digestibilities were evaluated in experiments with dogs (Canis familiaris), blue foxes (Alopex lagopus) and mink (Mustela vison) using seven extruded diets containing different protein sources. Four dogs (German shepherd), four blue foxes and four mink were offered each of the experimental diets to determine apparent total tract digestibility. Average digestibility of crude protein (CP) in blue foxes and mink was similar, and lower than the corresponding value in dogs (0·834 and 0·831 v. 0·864) (P < 0·001). CP digestibility in blue foxes showed significant correlations with dogs and mink (P < 0·05), while no significant correlation was observed between dogs and mink. Average digestibility of most amino acids was significantly lower in blue foxes than in dogs (P < 0·001), whereas mink digested most essential amino acids at the same level as did dogs. Most non-essential amino acids were digested at a significantly lower rate in the mink than in the dog and the blue fox (P < 0·001). There were significant correlations in the digestibility of most amino acids between dogs and blue foxes, and between blue foxes and mink (P < 0·05). Correlations were significant between dogs and mink for the digestibility of most essential amino acids (P < 0·05) but not significant (P > 0·05) for several non-essential amino acids. Average digestibility of crude fat was high and similar among the species studied: 0·968, 0·967 and 0·959 in dogs, blue foxes and mink, respectively. Average digestibility of starch ranged from 0·971 in mink to 0·998 in dogs; significantly higher in dogs than in blue foxes and mink, and significantly higher in blue foxes than in mink (P < 0·001). It was concluded that digestibility determined with mink, blue foxes or dogs may be used to predict digestibilities in the other investigated species. However, both the characteristics of the protein sources as well as the individual amino acid studied will influence the difference in digestibility among the species.

Abstract Fifty intact male Barbarine lambs were used to assess the effects of restricted feeding and re-alimentation on intake, growth and non-carcass components. Five lambs were slaughtered at the start of the trial, the remainder were randomly allocated into three groups. One group was offered only stubble grazing (low: L), another, also on stubble, received, indoors, an average of 80 g dry matter (DM) of soya-bean meal per day (medium: M); the third group was kept indoors and had free access to hay and 450 g of concentrate per day (high: H). At the end of this restriction period (70 days), five lambs per group were slaughtered. The 10 remaining animals in each group were divided into two groups receiving concentrate and hay ad libitum. The crude protein content (CP) of the concentrate was 160 and 210 g/kg DM for the two treatments, respectively. At the end of the trial all animals were slaughtered at 37·61 ± 2·05 kg live weight.

In the restriction period, sheep from the H group had a significantly higher growth rate (108 g/day) than L group (61 g/day) with M intermediate. The empty body weight (EBW) as well as carcass weight were significantly higher in H than in restricted sheep. Digestive tract components and liver weight were the same for all treatments. However, skin weight was significantly (P < 0·01) affected by dietary treatment. The heart and lungs were also heavier in H lambs than in the two other groups. Conversely, the relative weights of gut and liver as proportion of EBW increased in restricted lambs, while that of skin and red organs was not affected by diet.

In the re-alimentation period and with both CP levels, the compensating animals showed the same growth rate as the previous unrestricted ones. At the end of this period, organ weights, in both absolute and relative value, were comparable among lambs of the three nutritional histories and two CP level. The absolute and proportional daily gains were similar in all animals for visceral and external organs, but they were significantly higher in H lambs than in L and M ones for the omental and mesenteric fat and testis.

The faecal egg count (FEC) and total egg output is reduced in parasite-resistant sheep and breeding sheep for resistance should reduce infective larval contamination of pastures. This research compares lambs and rams from the parasite-resistant flock, Rylington Merinos, with unselected controls at the same level of larval challenge and the same level of food supply in an animal-house environment. The sheep were penned individually. The parasite resistant sheep excreted 0·85-fold less eggs than the control animals after infection with Trichostrongylus colubriformis and Ostertagia circumcincta for 12 or 18 weeks. During the infection period the parasite resistant lambs had higher plasma immunoglobulin concentration and higher ratio of globulin to albumin than the control animals. In the mature rams these genotype differences diminished. They also had lighter mass of the small intestine with a higher proportion of mucosa, but heavier mass of the large intestine. Parasite infection caused a depletion of blood glutathione in the lambs given food at maintenance or 1·5 × maintenance, and the parasite-resistant sheep (both lambs and rams) also had lower glutathione concentration. Maintaining good body nutrient reserve before the infection reduced the egg output in the early stage of the infection. Food intake had little effect on worm egg production in young sheep given food at maintenance or above. It is suggested that an improvement of nutrition, sulphur-containing amino acids in particular, is required to recover the loss of productive performance caused by the infection.

Abstract Fifty intact male Barbarine lambs were used to assess the effects of restricted feeding and re-alimentation on carcass composition and fatty acid (FA) composition of intramuscular fat. Five lambs were slaughtered at the start of the trial; the remainder were randomly allocated to three groups. One group was offered only stubble grazing (low: L), another, also on stubble, received, indoors, an average of 80 g dry matter (DM) of soya-bean meal per day (medium: M); the third group was kept indoor and had free access to hay and 450 g of concentrate (high: H). At the end of this restriction period (70 days), five lambs per group were slaughtered. The 10 remaining animals in each group were divided into two groups receiving concentrate and hay ad libitum. The crude protein (CP) content of the concentrate was 160 and 210 g/kg DM in the two treatments, respectively. At the end of the trial all animals were slaughtered at 37·61 ± 2·05 kg live weight.

In the restriction period, bone tissue was similar in terms of mass for all diet treatments. The absolute weight of muscle and fat in carcasses was higher for unrestricted sheep (H) than for restricted ones, but L and M lambs had proportionately less fat and more muscle than those given food indoors. Intramuscular fat composition was similar for all the treatments. During this period, the carcass gain of M lambs had the highest proportion of muscle and the lowest fat concentration, which is the better composition. At the end of the compensating period, all carcasses contained the same quantity of bone and muscle, but unrestricted sheep had significantly more fat than compensating ones. So, carcasses of compensating animals contained relatively less fat (240 v. 310 g/kg) and more muscle (550 v. 500 g/kg) than unrestricted ones. The carcass gain of lambs with an earlier nutritional history on L had the highest muscle and the lowest fat concentration. The intramuscular lipid composition in terms of fatty acids showed differences between treatments. Unrestricted animals contained more C14: 0 and C16: 0 and compensating animals more C18: 2 and a higher proportion of polyunsaturated fatty acids (PUFA) and PUFA: saturated FA ratio. There were no significant differences associated with CP level during the re-alimentation period

Simmental × Holstein-Friesian steers were offered four forage diets. These comprised grass silage (G); proportionately 0·67 grass silage, proportionately 0·33 maize silage (GGM); 0·33 grass silage, 0·67 maize silage (MMG); maize silage (M) from 424 (s.d. = 11·5) kg to slaughter at a minimum weight of 560 kg. Forages were mixed and offered ad libitum. Steers were offered 2 kg of a concentrate daily, the concentrate being formulated such that all steers had similar crude protein intakes across dietary treatments. A sample of steers was slaughtered at the beginning of the experimental period to allow the calculation of the rate of gain of the carcass and its components. Carcass dissection of a sample of steers allowed the development of a prediction equation of carcass composition based on thoracic limb dissection of all carcasses. Forage dry matter intake and live-weight gain increased linearly as maize silage replaced grass silage in the forage mixture, resulting in improvements in food conversion ratio (all P = 0·001). Killing-out proportion increased with maize silage inclusion (P < 0·001) but fat and conformation scores did not differ significantly between diets. However, increasing maize inclusion in the diet resulted in a greater weight (P = 0·05) and proportion (P = 0·008) of fat in the carcass, and significant increases in internal fat deposition. The inclusion of maize led to a progressive increase in the daily gains of carcass (P < 0·001), and significant increases in the daily gains of both fat (P < 0·001) and lean tissue (P < 0·001). Fat colour was more yellow in cattle given diets G and GGM than diets MMG and M(P < 0·001) and colour intensity was lower on diet M than the other three diets (P < 0·001). There were no significant differences in any aspects of eating quality between diets. Therefore, maize silage has the potential to reduce the time taken for finishing beef animals to achieve slaughter weight with no apparent detrimental effects on subsequent meat quality.

Two experiments were completed with grower-finisher pigs to determine if pigmeat output, as measured by carcass gain per m2 per year, could be increased, by 1: increasing group size or 2: split-marketing pen groups. In experiment 1, 390 pigs (mean initial live weight 36·7 (s.d. 1·99) kg) were assigned to one of three treatments each with 10 replicates: 11, 13 or 15 pigs per single-sex group in pens measuring 11·04 m2. Space allowance was 1·00, 0·85 and 0·74 m2 per pig, respectively. Pelleted food was provided ad libitum. There were no differences (P > 0·05) between group sizes in growth rate, food intake, food conversion ratio, carcass growth and carcass food conversion ratio, backfat and muscle depth or carcass lean content. Pigmeat output per unit area increased with each increase in group size (234, 279 and 314 kg/m2 per year for 11, 13 and 15 pigs: P < 0·001). In experiment 2, 26 groups of 13 pigs (mean initial live weight 38·3 (s.d. 2·15) kg) were assigned to one of three treatments: 1D - group sold on 1 day (no. = 9), 2D - group sold over 2 days (14 days apart, no. = 10), or 3D - group sold over 3 days (each 7 days apart, no. = 7). Pigs were given a standard liquid diet three times daily. No differences (P > 0·05) were observed between treatments for overall growth rate, food intake, food conversion ratio, carcass weight, carcass lean content, backfat and muscle depth, carcass growth and carcass food conversion ratio or killing-out proportion of pigs. Split-marketing increased cycle length (67·7, 75·9 and 76·8 days for 1D, 2D and 3D, respectively; P < 0·001). Live and carcass daily growth rates per pig place decreased with increase in number of sale days (live: 772, 680, 670 g/day and carcass: 658, 575, 571 g/day; P < 0·001). Carcass gain per unit area decreased in split-marketed groups (358, 318, 312 kg/m2 per year for 1D, 2D and 3D, respectively: P < 0·05). Carcass weight variation (s.d.) within pen decreased with each increase in number of sale days (s. d. 5·28, 3·81 and 1·74, respectively; P < 0·001). In conclusion, pigmeat output, as measured by carcass gains per m2 per year, was improved with increase in group size and by marketing all pigs in a group on a single day.

It is well established that the genetic merit of the Holstein-Friesian dairy cow for milk production has increased over the past 20 years. Previous studies have examined the effect of feeding system on indices of body tissue reserves of medium genetic merit Holstein-Friesian dairy cows. The aim of the current study was to examine the weight and concentration of body components in high genetic merit Holstein-Friesian dairy cows, managed on four different grassland-based feeding regimes, using direct measures of body composition. Results indicate that there was no significant effect of different grassland-based feeding regimes on the weight or composition of body components of high genetic merit cows. Therefore, high levels of cow performance can be sustained from very different grassland-based systems of milk production without having a detrimental effect on body tissue reserves.