Grazing animals cause major alterations to vegetation structure and botanical composition through their selective grazing, trampling and excretal deposition (Hester et al., 2005). Through these effects they modify habitats and thus the populations of invertebrates and other organisms at higher trophic levels. Herbivores are thus key drivers of ecosystem function and nutrient dynamics within grazed plant communities. Changes in grazing intensity and the species mix of grazing livestock can therefore have important implications for resulting biodiversity. Ongoing reform of the European Union Common Agricultural Policy (CAP) will lead to a shift in the way financial support for livestock is distributed and hence to changes in grazing management practices. Farmers will increasingly receive financial support subject to cross-compliance with various environmental conditions and for delivery of specific environmental and social objectives. In some areas, livestock are likely to be increasingly viewed as tools for habitat management rather than solely as producers of food and other commodities.

Against this backdrop of policy change the British Society of Animal Science and the British Ecological Society organized a joint symposium at the BSAS Annual Meeting in April 2005 on the links between farm animals and biodiversity. Four papers from this symposium are presented as mini-reviews in the current issue of Animal Science.

David Oglethorpe set the policy context in his review of the environmental implications of CAP reform (Oglethorpe, 2005). His paper highlighted the likely changes in the livestock sector that will ensue including a polarization of agriculture into intensive producers versus environmental managers, increasing extensification in the uplands and some substitution of beef with sheep. Jerry Tallowin then presented a review of the impact of grazing management on grassland biodiversity (Tallowin et al., 2005). His paper showed that lenient grazing pressure by cattle in species-rich grassland was sufficient to maintain botanical diversity but did not enhance it over a 5-year period. For species-poor grassland, grazing management could alter sward structure but, in the absence of seed sources, botanical diversity was resistant to change. There is obviously much research still be done in this area to support the development of suitable agri-environment measures under Pillar 2 support mechanisms. David Buckingham went on to consider the extent to which grassland management might influence habitat quality for farmland birds (Buckingham and Peach, 2005). His paper showed that the exacting requirements of declining granivorous birds pose the greatest challenges while the needs of soil invertebrate feeding species are more easily met under agri-environmental schemes. In the final paper by Bruno Martin, the influence of pasture diversity on cheese quality was the theme (Martin et al., 2005). This paper reviewed recent work, primarily from France, which has examined the links between the diet of grazing animals and the sensory characteristics of various Protected Designation of Origin cheeses. The review highlighted the sometimes subtle, but none the less important influence of the grazing environment on food quality.

The purpose of the symposium was to draw together animal scientists, conservation biologists, ecologists and socio-economists to consider the changing rôle of farm livestock within the new ‘decoupled’ economic environment. Judging by the popularity of the symposium and the vibrant nature of the discussion that followed each paper, there are plenty of issues still to consider and the hope is that some of the contacts made at the meeting will yield fruitful collaborations in the future.

On 1 January 2005, the direct support schemes directed at UK livestock farmers as part of the Common Agricultural Policy (CAP) were replaced with a Single Farm Payment, decoupled from production. In practical term, this means that farmers now have freedom of choice over the particular farm enterprises they engage in since their income support is no longer dependent on their type of production. Farmer policy-response will be dependent on their previous dependence on the direct subsidies being replaced, which, as the paper shows, is considerable for UK livestock farmers. The paper suggests a dichotomous shift of farmer objective in the livestock sector in the future, with ‘environmental managers’ and ‘market managers’ focusing on different outputs. The outcome will be a significant down-sizing of the UK livestock sector but with probable net gains to the environment.

This paper reviews recent work carried out by the Institute of Grassland and Environmental Research and collaborating organizations that addresses some of the impacts of grazing management on both species-rich and species-poor lowland neutral grassland. Results indicate that for species-rich grassland, lenient grazing pressure maintained botanical diversity and the abundance of positive indicator species of nature conservation value over a 5-year period and also enhanced faunal diversity and abundance reflecting improvements in spatial, architectural and temporal structure. However, there was no enhancement in positive indicator species and there was also an increase in pernicious weeds suggesting that grazing alone may not suffice to deliver all the biodiversity goals for these grasslands and that additional management interventions may be required. For species-poor grassland, results indicate that distinctive differences in structure can lead to differences in faunal diversity. There is also some tentative evidence that livestock breed may affect invertebrate species assemblages.

Abstract This review covers research linking foraging habitat quality for birds to livestock management in lowland farmland. Based on this research we propose a framework for predicting the value of grazing systems to birds. This predictive framework is needed to guide the development of agri-environment measures to address farmland bird declines in pastoral areas. We show that the exacting requirements of declining granivorous birds pose the greatest challenges, while the needs of soil invertebrate feeding species are more easily met.

Abstract This review summarizes the recent developments in understanding of the relationships between the diet of animals and the sensory quality of dairy products. Feeding dairy cattle with maize silage by comparison with hay or grass silage leads to whiter and firmer cheeses and butter and sometimes to differences in flavour. Major differences in sensory characteristics were observed between cheeses made with milk produced by cows on winter diets (based on hay and grass silage) or turned out to pasture in the spring. Conversely, preserving grass as silage, by comparison with hay, has no major effect on cheese sensory characteristics, except on colour, the cheese being yellower with grass silage. Several recent experiments have shown a significant effect of grass botanical composition on cheese texture and flavour. These effects are due to the presence in milk of specific molecules directly introduced by feeding (carotenes, terpenes) or produced by the animals (plasmin, fatty acids) under the effect of specific diets.

Abstract Acute phase proteins (APP) are released into the circulation in mammals upon infection and may be used to diagnose the health status of managed populations of animals such as pigs. The current study determines APP levels in a population of apparently healthy Large White pigs from a single farm, to address two questions: (1) whether phenotypic associations can be observed between productivity and APP, indicating the effects of possible subclinical infections and (2) whether previous selection for either food intake or ‘lean growth under restricted feeding’ influences APP levels. The APP investigated were alpha1- acid glycoprotein (AGP) and haptoglobin. The APP were measured at 18 and 24 weeks of age in pigs previously selected for high lean growth (no. = 31), low lean growth (no. = 38), high daily food intake (no. = 24) and low daily food intake (no. = 26), but performing under ad libitum feeding conditions. Performance traits and APP levels were constant over the experimental period, indicating that the farm health status did not vary over time. Performance traits and APP were recorded on 119 pigs, of which 80 had both APP and performance measurements. Multiple regression analyses were used to investigate phenotypic relationships between performance traits and APP levels. Plasma concentrations of AGP were higher in 18-week-old pigs compared with 24-week-old pigs (P < 0·01) whereas haptoglobin levels did not vary according to age. Significant sex differences in APP levels were observed. Females had higher circulating levels of AGP than males at both 18 weeks and 24 weeks. Females also had higher levels of haptoglobin at 18 weeks. Levels of AGP had significant negative correlations with daily weight gain (−0·59, P < 0·01 and −0·48, P < 0·05 at 18 and 24 weeks respectively) and with daily food intake (−0·53, P < 0·01 and −0·38, P < 0·05 at 18 and 24 weeks respectively). At age 24 weeks, haptoglobin was negatively correlated with both daily weight gain (−0·35, P < 0·05) and food efficiency (−0·34, P < 0·05). Pigs selected for high lean growth under restricted feeding had higher AGP levels than pigs selected for low lean growth under restricted feeding at 18 (593 v. 332 μg/ml, P < 0·01) and 24 weeks of age (313 v. 219 μg/ml, P < 0·05). Selection for daily food intake did not consistently affect AGP levels, and neither selection criteria influenced plasma haptoglobin concentrations. To conclude, we have demonstrated that amongst contemporaneous pigs of the same genotype, higher systemic AGP levels and, to a lesser extent, higher haptoglobin levels are associated with decreased performance, and that genetic selection for ‘efficient lean growth under restricted feeding’ can increase serum AGP levels.

A maternal breeding goal for the UK beef industry is described and economic selection indexes are developed to assist in the selection of animals for the goal. The breeding objective is made up of general maternal ability traits, cow size, calving and carcass traits. The general maternal ability traits include calving interval, age at first calving, lifespan, maternal weaning weight and maternal calving difficulty. The calculations of economic values for the traits are outlined and discounted genetic expression coefficients are presented. Three selection indexes are illustrated. The first provides a general dualpurpose index for the selection of bulls to produce replacement heifers in most situations. The second, the hardy breed index, is designed to allow selection for improved maternal performance in extensive and hardy environments. The third, the fertile herd index, allows producers who do not have herd fertility problems to place more selection emphasis on objectives other than fertility. A sample of data from the Limousin breed was used to calculate estimated breeding values (EBVs) which were used to investigate response to the three indexes when the top 20% of sires were selected from either sires with 50 or more grand-maternal progeny or bulls with no recorded progeny. Approximately two thirds of the economic response seen in the selection of heavily used bulls was observed in bulls with no progeny for the hardy and dual-purpose indexes. Bulls were also selected using the existing UK terminal sire index and the resulting bulls assessed in the dual-purpose maternal index. There was found to be a negative economic response to the maternal aspect of the index, though a positive response was seen in the carcass objective. The indexes are presented as the sum of four subindexes emphasizing the contribution of maternal ability, cow size, calving and carcass, respectively to the total index. This further assists commercial producers in selection decisions.

Parameters of daily milk yield during the first three lactations of Chios ewes were estimated with random regression models. Data consisted of 42 675 test-day records of 7121 ewes from 75 flocks that had lambed between 1998 and 2000. Models fitted fourth order fixed regressions on Legendre polynomials of the number of days post partum and fourth order random regressions on the individual animal. (Co)variance components were estimated with Gibbs sampling. Lactations were analysed separately. The four eigen values accounted for 0·80 to 0·84, 0·11 to 0·15, 0·04 to 0·05 and about 0·01 of the animal variance, respectively, depending on lactation number. Animal variance estimates, including genetic and, partly, permanent environment effects, were high at the beginning of each lactation and decreased as lactation progressed, suggesting that the animal effect is most important to early daily records. Residual variance was highest in the middle of lactation, suggesting that non-systematic environmental factors play a bigger at that time. Animal correlation estimates between daily yield records ranged from 0·26 to 0·99, were highest for adjacent days and decreased for days further apart. The decline had a different shape in the three lactations and was more evident in the first, suggesting that the three lactations may be biologically distinct traits. Animal correlation estimates between daily and total lactation milk yield ranged from 0·61 to 0·98 and were highest in the middle and lowest towards the end of lactation. Early lactation daily yield had an animal correlation of 0·70 to 0·80 with total lactation milk yield, in all three lactations. Results of this study suggest that daily milk yield records in the early stages of lactation may be useful for selection of ewes with high producing ability and accurate prediction of total lactation milk yield.

Six cannulated wether sheep weighing 57 (s.d. 4·3) kg were used to investigate the susceptibility of unprotected and protected n-3 polyunsaturated fatty acids from different sources to biohydrogenation in the rumen, their uptake into plasma and effects on ruminal metabolism. The sheep were assigned to one of six dietary treatments formulated to have a similar fatty acid content (60 g/kg DM) and containing: linseed oil (LO), linseed oil absorbed into vermiculite (VLO), formic acid-formaldehyde treated whole linseed (FLS), fish oil (FO), fat encapsulated fish oil (PFO) or a mixture of fish oil and marine algae (1: 1 on an oil basis; AF), in six periods of 28 days duration in a Latin-square design. Biohydrogenation of C20:5 (n-3) and C22:6 (n-3) was high in FO at approximately 870 g/kg, but reduced to 625 and 625 g/kg respectively for PFO, and 769 and 601 g/kg respectively for AF. Ruminal biohydrogenation of C18:3 (n-3) was similar across treatments based on linseed, averaging 860 g/kg, but C18:2 (n-6) was lower (P < 0·05) in animals given VLO or FLS at 792 and 837 g/kg respectively, compared with LO (907 g/kg). Duodenal flow of C18:1 trans in animals given any of the diets containing fish oil averaged 8·4 g/day compared with 2·8 g/day in animals given diets based on linseed (P < 0·001), whilst cis-9, trans-11 conjugated linoleic acid was not significantly different among treatments. Plasma C20:5 (n-3) and C22:6 (n-3) proportions were highest in animals given the AF diet (11·8 and 8·2 g per 100 g of the total fatty acids respectively) and lowest in animals given LO (2·8 and 2·7 g per 100 g of the total fatty acids respectively; P < 0·001). By contrast, plasma C18:3 (n-3) proportions were highest in animals given the LO or VLO diets at approximately 6·9 g per 100 g of the total fatty acids, and lowest in the AF treatment at 0·9 g per 100 g (P < 0·001). Duodenal non-ammonia-N flow was similar among treatments at 21·0 g/day except in animals given FLS which had the highest flow (25·9 g N per day; P < 0·01). Microbial N flow was also similar among treatments whilst microbial efficiency (g N per kg OM truly degraded in the rumen) was higher (P < 0·05) in animals given FLS than LO, FO or AF. By contrast, ruminal fibre digestion was higher (P < 0·05) in animals given LO or FO than those offered VLO, FLS, PFO or AF. In conclusion, compared with linseed oil, absorption of linseed oil into vermiculite improved duodenal flow but not plasma levels of C18:3 (n-3), whilst formic acid-formaldehyde treatment of linseed had little effect on protecting C18:3 (n-3) in the rumen, although duodenal non-ammonia nitrogen flow and microbial efficiency were improved. Compared with fish oil, the provision of marine algae or fat encapsulated fish oil resulted in a lower biohydrogenation of C22:6 (n-3) and C20:5 (n-3), and an increased duodenal flow and plasma concentration and offers the potential to favourably manipulate the n-3 fatty acid composition of sheep meat.

Three 28-day trials were carried out to determine the optimum dietary lysine concentration for growing pigs between 20 and 68 kg. There were 96 pairs of pigs in experiment 1 (20 to 41 kg), 72 pairs in experiment 2 (40 to 68 kg) and 42 groups (14 per group) in exp. 3 (40 to 62 kg). All experiments were arranged as randomized complete block designs, blocked on the basis of sex and start weight. Treatments consisted of isoenergetic (13·8 MJ digestible energy per kg) diets with increasing lysine concentrations. Dietary lysine concentrations were 9·7, 10·7, 11·6, 12·5, 13·5 and 14·4 g/kg (experiment 1) and 9·0, 9·9, 11·0, 12·1, 13·1 and 14·1 g/kg (experiments 2 and 3). Response curves were fitted to the data to determine the optimum dietary lysine concentration for maximum average daily gain (ADG) and minimum food conversion ratio (FCR). In experiment 1, ADG and FCR responded quadratically to dietary lysine content (P < 0·01 and P < 0·05). Male pigs had better FCR and lysine conversion ratio (LCR) than female pigs (P < 0·05). In experiment 2, there was a quadratic effect of increasing dietary lysine concentration on FCR (P < 0·05). Male pigs had lower daily food intake (DFI, P < 0·01) and daily lysine intake (DLYIN, P < 0·01) and had better FCR (P < 0·01) and LCR (P < 0·01) than female pigs. In experiment 3, there was a quadratic effect of increasing lysine concentration on FCR (P < 0·05). Male pigs had better FCR and LCR (P < 0·05) than female pigs. In all experiments, increasing dietary lysine concentration resulted in an increase in DLYIN and a deterioration in LCR (all linear, P < 0·001). Regression analysis predicted optimum dietary lysine concentrations for maximum ADG at 13·1 and 12·7 g lysine per kg in experiments 1 and 2, and minimum FCR at lysine concentrations of 14·6, 12·2 and 12·7 g/kg for experiments 1, 2 and 3 respectively. In conclusion, the optimum dietary lysine concentration for maximum ADG and minimum FCR could be predicted using quadratic models and although males had better FCR than females, optimum dietary lysine concentrations were similar for both sexes.

This experiment investigated the effects of feeding graded levels of a soya-bean protein product (HP300, Hamlet Protein A/S Company, Denmark) on endogenous ileal lysine loss, apparent ileal amino acid digestibility, standardized true ileal amino acid digestibility determined using the protein-free (PF) method, and real ileal amino acid digestibility determined using the homoarginine (HA) method. The soya-bean protein product was obtained by purifying and defattening soya bean via a proprietary microbial process that decreased the level of trypsin inhibitors and other anti-nutritional factors in soya bean. Six barrows, with an initial body weight of 37·4 ± 1·3 kg, were surgically fitted with simple T-cannulae at the distal ileum and offered six maize-starch-based diets according to a 6 × 6 Latin-square design. The six diets were formulated to provide 0, 50, 100, 150, 200, or 250 g crude protein (CP) per kg by dietary inclusion of 0, 90, 182, 274, 367 or 460 g/kg of soya-bean protein. Five kg of soya-bean protein product was guanidinated in order to estimate endogenous amino acid flow and real ileal amino acid digestibility. Chromium III oxide (5 g/kg) was included in the non-guanidinated diets while dysprosium chloride (0·1 g/kg) was included in the guanidinated diets as an indigestible marker. The experimental periods lasted 8 days. On day 6 of each period, ileal digesta was collected for 24 h to determine apparent and standardized true ileal amino acid digestibility of the non-guanidinated diets. At 08:00 h on day 8, the pigs were given a single meal of the diets containing guanidinated protein and their ileal digesta was collected for 24 h in order to determine the total HA flow and the real ileal digestibility of lysine. Endogenous ileal lysine flow appeared to follow a sigmoid curve starting at about 370 mg/kg dry matter (DM) intake for pigs given the PF diet and continuing asymptotically to about 750 mg/kg DM intake when the inclusion level of the soya-bean protein product was increased to 182 g/kg (100 g/kg of CP). The endogenous ileal lysine flow for pigs given the PF diet was similar (P > 0·05) to that of pigs given 90 g/kg soya-bean protein (50 g/kg of CP) and it increased sharply (P < 0·05) as the level of soya-bean protein increased from 90 to 182 g/kg (50 to 100 g/kg of CP). Thereafter, it was relatively constant (P > 0·05). With an increase in soya-bean protein, there was a quadratic increase (P < 0·01) in the apparent ileal digestibilities for all amino acids except valine and phenylalanine. Standardized true ileal amino acid digestibility decreased (P < 0·05) with an increase in soya-bean protein level. However, real ileal amino acid digestibilities were not influenced (P > 0·05) by soya-bean protein in the diet at levels between 90 and 367 g/kg (50 and 200 g/kg of CP). In conclusion, endogenous ileal lysine flow was not constant and was significantly affected by soya-bean protein level. The results of this study suggest that standardized true ileal amino acid digestibility should be measured between 100 and 200 g/kg of CP (182 and 367 g/kg soya-bean protein) while real ileal amino acid digestibility is unaffected by protein levels between 50 and 200 g/kg of CP (90 and 367 g/kg soya-bean protein).

Both barley and wheat contain anti-nutritive factors such as glucans and xylans respectively. However, β-glucans have been shown to promote lactic acid bacteria in the large intestine and this would be very beneficial in the absence of in-diet antimicrobial growth promoter. A 2 × 2 factorial was used to investigate the interaction between cereal type (wheat v. barley) and lactose inclusion (170 v. 275 g/kg) on piglet performance post weaning. Two hundred and sixteen weaned piglets (24 days of age, 6·0 kg weight) were blocked on the basis of weight and were assigned to one of four dietary treatments. The treatments were as follows (T1) 170 g/kg lactose and wheat, (T2) 275 g/kg lactose and wheat, (T3) 170 g/kg lactose, wheat and 200 g/kg barley and (T4) 275 g/kg lactose, wheat and 200 g/kg barley. The diets were formulated to have identical concentrations of digestible energy (16 MJ/kg) and total lysine (16 g/kg). The pigs were offered the diets ad libitum for 33 days post weaning. There was a significant interaction (P < 0·05) between cereal source and lactose level in average daily gain (ADG). In wheat-based diets the inclusion of 275 gkg lactose resulted in a significant improvement in ADG, compared with the 170 g/kg lactose inclusion. However, in barley-based diets the inclusion of 275 g/kg lactose significantly (P < 0·05) reduced ADG. There was no significant effect of cereal type or lactose level on food intake or food conversion ratio (FCR). The inclusion of 275 g/kg lactose significantly reduced nitrogen digestibility (P< 0·01). In barley-based diets, the high level of lactose inclusion depressed digestibilities of dry matter (P < 0·01), organic matter (P < 0·05) and gross energy (P < 0·05) compared with low lactose inclusion. However, in wheat-based diets, lactose level had no significant effect. In conclusion, improvements in performance were achieved up to 275 g/kg lactose in wheat-based diets. However, in barley-based diets a dietary lactose level of 170 g/kg was adequate.

Twenty-four twin-bearing mature Mule ewes were used to evaluate the effects of feeding ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) during late pregnancy on subsequent ewe and lamb performance. Eight weeks prior to lambing the ewes were individually penned and offered one of the treatment forages ad libitum (no. = 8 per silage). All ewes were supplemented with molassed sugar-beet shreds to avoid dietary energy being a limiting factor and to ensure the responses were primarily attributable to the forage protein content. Individual intakes of the ewes were determined daily and weekly measurements of ewe live weight and body condition score were made. The ewes were also scanned weekly for depths of subcutaneous fat and longissimus dorsi (LD) muscle. Blood samples were taken at 6, 4, 2, and 1 week(s) before lambing, 24 h after lambing and at 3 weeks after lambing and were analysed for serum concentrations of total protein (TP), albumin, urea, beta-hydroxybutyrate (BHB) and plasma concentrations of glucose and non-esterified fatty acid (NEFA). After lambing all ewes and their lambs were turned out to graze together on a ryegrass sward. The lambs were weighed at birth and at weekly intervals thereafter until 12 weeks post partum. The lucerne silage offered had a higher dry matter (DM) content than the red clover and ryegrass silages (367, 305 and 314 g DM per kg fresh matter, respectively; P < 0·001). Forage type significantly affected crude protein (CP) concentration (240, 215 and 182 g CP per kg DM for lucerne, red clover and ryegrass silages, respectively) and metabolizable energy (ME) density (11·1, 11·6 and 10·8 MJ ME per kg DM respectively). Ewes offered the legume silages had higher intakes of DM, CP and ME than ewes offered ryegrass silage (P < 0·05), which was reflected in higher ewe live-weight gain (P < 0·05) but not in litter birth weight (P > 0·05). Silage treatment affected serum concentrations of TP, albumin, globulins and urea during the last 4 weeks of pregnancy (P < 0·05). Lambs born from ewes offered lucerne and red clover silages prior to lambing had higher growth rates from birth to 3 weeks of age than those from ewes offered ryegrass silage (320, 323 and 282 g/day, respectively; P < 0·05). Lamb live weight at 12 weeks of age was higher for lambs from ewes that had been offered the red clover silage, at 29·1 kg compared with 26·7 and 27·1 kg for lambs from ewes previously offered lucerne and ryegrass silages (P < 0·05). In conclusion, the results showed that red clover and lucerne silages are better able to meet nutrient requirements of ewes in late pregnancy than grass silage.

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.

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).

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.

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.

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