In France, animal products (dairy products, meat and eggs) are the main source of n-3 polyunsaturated fatty acids (PUFA) in the human diet; however, many individuals do not consume enough of this nutrient. The objective of this study was to increase n-3 PUFA precursor and derivative contents in tissues and test how they influence technological and sensory qualities of meat without negatively affecting growth performances of pigs. A total of 60 male pigs [(Large White×Landrace)×Pietrain] were assigned according to their initial liveweight (50.7±2.7 kg) to five experimental groups corresponding to five different diets that they received from 14 to 22 weeks of age. Dietary lipid supplements were composed of soybean and palm oil (SP), dehulled and extruded linseed (EL-), docosahexaenoic acid (DHA)-rich microalgae (MAG) or a mixture of linseed and microalgae at 75%/25% (3EL-/MAG) and 50%/50% (EL-/MAG), respectively. Diet did not influence growth performances of pigs or the technological quality of the meat. The n-3 PUFA content in the longissimus dorsi muscle, subcutaneous backfat (SCB) and liver increased with a dietary supply of linseed and microalgae and corresponded to circulating fatty acids (FA). The amount of malondialdehyde, representative of FA lipid peroxidation measured in SCB, increased significantly with the supply of microalgae, meaning that PUFA from the microalgae included in the diet increased the meat’s susceptibility to oxidation. The MAG diet scored highest for ‘abnormal’ flavor, similar to that of fish or organ meat, but the n-3 PUFA-rich diet had no effect on other sensory characteristics. Results of this study indicate benefits of enriching animal feed with n-3 PUFA, but the inclusion of long-chain n-3 PUFA such as DHA must be limited to avoid oxidation susceptibility and development of an off-odor.

Two studies investigated the effect of contaminated pasture on selective grazing, overall grazing behaviour and the process of defoliation of dung patches through experiments targeted at four major questions: (a) how does relative utilization of tall and short grass change as the sward is grazed down? (b) what effect does herbage mass and sward height have on the relative utilization of short and tall grass? (c) how are tall grass patches actually utilized by cattle? and (d) how is overall grazing behaviour influenced by contamination of the sward?

Experiments were conducted in mid to late season using Friesian dairy cattle. In experiment 1, two -pasture types (topped sward (T) v. grazed-only sward (G)) were used. The distribution of bites on tall grass from both pasture types indicated that the grazing animals tended initially to graze short grass when they met a new sward, and then select tall grass as the swards were progressively grazed down. This switch happened earlier in the defoliation process in the topped sward. In experiment 2 observations were conducted on previously grazed and previously ungrazed swards. The distribution of bites on tall grass showed a similar trend to that found in experiment 1 and as the sward was gradually grazed, biting rate significantly declined. There was also a significantly higher total grazing time on the previously ungrazed sward (no contamination by dung). Comparing data based on a consistent biting rate (calculated as the time for 20 consistent bites) and natural biting rate (calculated as the total time for 20 bites) suggested that the grazing animals had increased difficulty in handling tall grass which may explain the declining biting rate as the swards were being grazed down and more bites were directed at tall grass. The defoliation of tall grass dung patches appeared to be concentrated around the edges of the patch. The average area of sward affected by a single dung pat was 1·04 m2 measured at the pre-grazing stage and was markedly reduced to 0·51 m2 at the post-grazing stage. In conclusion, selective grazing is likely to exist due to the presence of dung and conditioned by dung distribution and sward type and this in turn modifies biting rate during grazing down of a sward.

1. An experiment was carried out with forty individually-fed Large White × Wessex pigs to examine the growth rates of females (gilts) and castrated males after varying periods of time on a restricted plane of nutrition.

2. Compensatory growth was made by pigs in all treatments when some restriction in the plane of nutrition had been previously imposed.

3. The immediate growth response after the restriction ceased was directly related to the duration of the period of restriction.

4. In pigs on a restricted scale of feeding to 80 lb. live-weight, no compensatory growth was observed until a later stage in growth, whereas pigs on a restricted scale for a much longer period to 160 lb. live-weight showed immediate and significant compensatory growth.

5. In the periods immediately after the food restriction was lifted, gilts responded more than castrated males on all treatments.

6. The effect on the overall growth rate from 45 to 200 lb. live-weight became progressively worse as the period of restriction was prolonged and in no case did the compensatory growth fully compensate for the setback suffered during restriction.

7. There were no significant differences in overall food conversion efficiency and it appears that pigs with an even rate of gain and an interrupted growth rate may be equally efficient.

8. There were no significant differences in carcass length or dressing-out percentage although a moderate degree of restriction up to 120 lb. live-weight improved grading results, these being related, to non-significant improvements i n food conversion and therefore possibly to a lower carcass fat content.

1. In vivo gastric pH changes were studied, in 6 pigs fitted with permanent gastric cannulae, under ‘basal conditions’ (i.e. when no food was given) and when diets containing 85% of differently processed barley were given either twice daily or at frequent intervals of time in an attempt to simulate ad libitum feeding systems. Before inclusion in the diet the 85% of barley had either received no processing (i.e. was given as the whole grain) or had been processed in one of the five following ways: (a) ground through a (1·56 mm) screen (b) ground through a (4·68 mm) screen (c) ground through a (9·36 mm) screen (d) coarsely crimped (e) cold rolled.

2. Relative to the ‘basal’ determinations the systems of feeding which gave food at frequent intervals of time induced higher overall mean pH values than did those which gave food twice daily, while between the six differently processed diets those containing the smaller particles of barley tended to give higher overall mean pH values than did those containing the coarser particles.

3. The validity of the results is discussed in the context of the techniques used and some possible implications in terms of animal health are briefly discussed.

Phytase enzyme is used as a dietary supplement in broiler nutrition to improve phosphorous bioavailability. Phytase deliberates phosphate groups from phytic acid and produces myo-inositol after total dephosphorylation. Myo-inositol is a bioactive compound having beneficial modulatory effects on metabolism in humans. However, it is not well understood if and how phytic acid degradation products, particularly myo-inositol, can modulate metabolism in broiler chicken. The purpose of this study was to investigate effects of dietary supplements of phytase and myo-inositol on the blood plasma metabolome profile of broiler chickens. Broilers were provided a nutrient-adequate control diet or the same diet supplemented with either 3.5 g myo-inositol or 500, 1500 or 3000 units of phytase, per kilogram of feed (grower diet). Broilers were group-housed in floor pens (eight pens per diet) and provided one of the treatment diets for 22 days. Then, blood was collected from one bird per pen, resulting in eight replicated measurements per diet. A targeted metabolomics approach was applied to the heparin plasma. Body weight of the birds was not significantly affected by the treatments. Plasma myo-inositol concentrations were significantly increased by myo-inositol supplementation and phytase supplementation at 500 and 1500 units/kg. Metabolites generally affected by phytase supplementation belonged to the groups of acyl-carnitines, phosphatidylcholines, sphingomyelins, lysophosphatidylcholine, biogenic amines and amino acids. Compared to the control diet, phytase supplements had significantly higher plasma concentrations of kynurenine and creatinine, but lower concentrations of histamine and cis-4-hydroxyproline. Myo-inositol supplementation significantly increased plasma concentrations of dopamine and serotonine. While some metabolites were similarly affected by myo-inositol and phytase supplementation, others were distinctly differently affected. We conclude that myo-inositol, either as a directly added supplement or indirectly released from phytate upon phytase supplementation, can affect specific metabolic pathways. Additional effects found on phytase supplementation may be related to intermediary phytate degradation products. Results are indicative for innovative hypothesis to be tested in future experiments, for instance, with regard to relationships between phytase or myo-inositol supplements and bird immunity or behaviour.

Two fat blends differing in free fatty acid concentration and fatty acid composition were included in cereal-based diets at concentrations of 10, 30, 50, 70, 90 and 110g/kg. The digestible (DE) and metabolizable (ME) energy of each diet were estimated in a metabolism experiment based on three 4 × 4 Latin squares using gilts of 30 kg initial live weight fitted with indwelling bladder catheters. With increasing dietary fat both DE and ME increased linearly (P < 0·001) and the linear equations derived were used to calculate the DE values of the two fats by extrapolation. Values were 26·4 and 24·2 MJ/kg respectively for fats A and B. The change in dietary D E and ME to increasing dietary fat concentration showed a curvilinear trend (P = 0·0987 and 0·1268 respectively for DE and ME ) indicating that fats may not be correctly evaluated at only one rate of inclusion. The quadratic functions derived were interpolated to provide DE and ME data for the two fats. Values for DE for fat A ranged from 32·7 o t 25·7 MJ/kg at 10 and HOg/kg, and for fat B from 38·6 to 26·3 MJ/kg at 10 and 110 g/kg. Data for ME followed similar trends. It was concluded that multi-level assays are important in the evaluation of fats and that the rate of decline of fat DE and ME was specific to the fat examined.

The effect of level of concentrate supplementation on the grazing behaviour of lactating Holstein-Friesian cows was examined over three periods on continuously stocked grass swards maintained between 7 and 8 cm sward surface height (SSH). A dairy concentrate containing 180 g crude protein per kg fresh weight was offered at 0, 1·2, 2·4, 3·6, 4·8 or 6·0 kg fresh weight per day in two equal feeds during milking. Grazing and ruminating behaviour was recorded automatically over 24 h using sensors to measure jaw movements. Intake rates were calculated by weighing cows before and after approximately 1 h of grazing, retaining the faeces and urine excreted and applying a correction for insensible weight loss. Details of jaw movements were also recorded during these grazing periods. Level of supplementation did not significantly affect short-term intake rate of herbage or total eating time during grazing over the day, which varied between 15 and 21 g organic matter per min and between 530 and 600 min/day respectively. Supplementation had no effect on ruminating behaviour. Increasing the level of supplementation produced a significant linear increase in milk yield. The results show that at the level of grass intake achieved on continuously stocked swards maintained at 7 to 8 cm SSH, daily intake of up to 6 kg concentrates does not significantly affect grazing behaviour or lead to substitution of the grazed herbage.

A total of 160 Duroc×(Landrace×Large White) pigs, 50% barrows and 50% gilts, of 28.3±4.52 kg of BW were used to study the effect of lysine (Lys) restriction in the finisher period, on growth performances and serum and carcass and meat quality traits. The grower diet (from 30 to 90 kg BW) was slightly Lys-restricted (7.8 g standardised ileal digestible (SID) Lys/kg) in accordance with results from a previous trial. During the finisher period (90 to 130 kg BW), four experimental diets with decreasing SID Lys contents (6.3, 5.6, 4.2 and 3.2 g/kg) were tested. Each of the eight treatments (two sexes×four levels of Lys) was replicated five times. Each replicate was a pen with four pigs allocated together. When animals achieved 129±2.59 kg were slaughtered and carcass and meat characteristics were evaluated. No significant interaction sex×diet was found. During the finisher period, barrows grew faster (P<0.001) and ate more feed (P<0.001) but tended to be less efficient (P=0.055) than gilts. The Lys restriction affected linearly (P<0.001) all productive performance traits; daily BW gain and feed intake decreased and feed conversion ratio increased. Also, the concentration of serum urea at slaughter tended to be higher in barrows than in gilts (P=0.065) and was reduced quadratically by the restriction of Lys in feed (P<0.001). Carcasses from barrows had higher backfat thickness (P<0.01) and lower weight of main trimmed lean cuts (ham+shoulder+loin; P<0.05) than those from gilts. The Lys restriction during the finisher period decreased carcass yield (quadratic; P<0.001) and the weight of major cuts (linear; P<0.001). Sex and diet had limited effect on meat characteristics; the Lys restriction decreased quadratically the proportion of protein (P<0.01) and increased linearly the intramuscular fat (IMF) content (P<0.001). We can conclude that dietary Lys restriction during finisher period in pigs impaired growth performances and was not successful to increase the carcass fat deposition, although it could have positive effects on IMF proportion of pork.

Genetic parameters were calculated for fibre traits measured on patch samples taken at 5 months of age on a crossbred population of cashmere goats, comprising goats of Scottish feral, Icelandic, Tasmanian, New Zealand and Siberian origin. Within-strain heritabilities, fitting genetic origin as a covariable, were: live weight, 0·71 (s.e. 0·08), fibre diameter, 0·63 (0·07), diameter standard deviation 0·43 (0·08), logipatch cashmere weight), 0·60 (0·06), log(estimated annual cashmere production), 0·51 (0·07), and fibre length, 0·49 (0·15). Including between strain information increased these values to 0·74, 0·68, 0·45, 0·73, 0·67 and 0·57, respectively. Maternal effects for all fibre traits were negligible. Expressions were derived to relate cashmere weight to fibre diameter and length, using functional relationships between these traits. Logarithmic regressions showed cashmere weight to be proportional to diameter2'7, indicating that selection to reducefibre diameter will have a disproportionate effect on cashmere weight. Analyses of subsets of the data confirmed this and showed that correlated responses to selection can be accurately predicted by considering thefunctionally relatedfibre traits on the log scale.

Red Maasai and Dorper sheep were evaluated for their resistance to gastro-intestinal (GI) nematode parasites (predominantly Haemonchus contortus), productivity and productive efficiency (assessed on a metabolizable energy basis) in experiments undertaken at the Kenyan coast (sub-humid environment) and the Kenya highlands (semi-arid environment). In both ewes and lambs there were few significant genotype by environment (G X E) interactions for either resistance (assessed by faecal egg counts-FEC) or resilience (assessed by blood packed red cell volume-PCV) to GI nematodes. Red Maasai sheep were consistently more resistant (low FEC) and more resilient (high PCV) than Dorper sheep. However, there were significant G X £ interactions for ewe reproductive performance and for ewe and lamb mortality rates and live weights. These interactions were due to very poor performance of the Dorper compared to the Red Maasai in the sub-humid coastal environment and to the much improved performance of the Dorper in the semi-arid environment. When these component traits were combined into estimates of flock productivity and productive efficiency there were highly significant GXE interactions with the Red Maasai sheep being considerably more efficient than Dorper sheep in the sub-humid environment, while in the semi-arid environment there was a negligible breed difference in productive efficiency. The results are discussed in terms of breeding strategies for smallholder farmers and pastoralists managing sheep in low-input systems in sub-humid and semi-arid environments.

Evidence from studies of group-housed sows in unbedded systems indicates that hunger may be a cause of increased aggression between animals. The present study aimed to investigate the effects of food level on performance, aggression and skin damage in a deep-straw system. Sixteen groups offive gilts were introduced over 8 months to one of two dynamic groups in a deep-straw yard (2·35 m2 per sow) receiving different food levels from an electronic sow-feeding system: high (H: 3·0 kg and 38 MJ/day) and low (L: 1·6 kg and 20 MJ/day). Seventy second-parity sows were returned to the same treatments in the same subgroups. The behaviour of the animals was recorded throughout both pregnancies using a time sampling technique. Severity of skin damage was recorded as a number from 0 to 4 for each of nine areas, the average of which being the ‘damage score’. The total number of animals in each dynamic group was maintained at around 30, through the use of additional sows. As expected, H sows were heavier than L sows but no effect offood treatment was found on litter size or performance. L sows were more active (L v. H; standing: 41 v. 31% of total observation time respectively, F114 = 7·65, P < 0·05) and showed more straw manipulation than H sows (L v. H: 17 v. 10% respectively, F 3 34 = 18·4, P < 0·001). No differences between treatments were found either in number of aggressive interactions (L v. H: 3·6 v. 3·8 interactions per sow per observation day, F, u = 0·82, P > 0·05), or in damage score (L v. H: 0·24 v. 0·28; Flu = 0·27; P > 0·05).

However, introduction of new animals did influence aggression, with sows being more involved in aggressive interactions on the day they were introduced, than on other sow's introduction days and on no introduction days (Tukey, P < 0·05). Average skin lesions per experimental sow were also higher in the days immediately following introduction. It can be concluded that in a sequential feeding system with plentiful straw, aggression is not influenced by the level offeeding. In these systems, the major factor giving rise to aggression is the introduction of new sows to the resident group.

From the simultaneous accumulation of hydrogenation intermediates and the disappearance of Isotricha prostoma after algae supplementation, we suggested a role of this ciliate and/or its associated bacteria in rumen biohydrogenation of unsaturated fatty acids. The experiments described here evaluated the role of I. prostoma and/or its associated endogenous and exogenous bacteria in rumen biohydrogenation of C18:2n-6 and its main intermediates CLA c9t11 and C18:1t11. Fractions of I. prostoma and associated bacteria, obtained by sedimentation of rumen fluid sampled from a monofaunated sheep, were used untreated, treated with antibiotics or sonicated to discriminate between the activity of I. prostoma and its associated bacteria, the protozoan or the bacteria, respectively. Incubations were performed in triplicate during 6 h with unesterified C18:2n-6, CLA c9t11 or C18:1t11 (400 μg/ml) and 0.1 g glucose/cellobiose (1/1, w/w). I. prostoma did not hydrogenate C18:2n-6 or its intermediates whereas bacteria associated with I. prostoma converted a limited amount of C18:2n-6 and CLA c9t11 to trans monoenes. C18:1t11 was not hydrogenated by either I. prostoma or its associated bacteria but was isomerized to C18:1c9. A phylogenetic analysis of clones originating from Butyrivibrio-specific PCR product was performed. This indicated that 71% of the clones from the endogenous and exogenous community clustered in close relationship with Lachnospira pectinoschiza. Additionally, the biohydrogenation activity of solid-associated bacteria (SAB) and liquid-associated bacteria (LAB) was examined and compared with the activity of the non-fractioned I. prostoma monofaunated rumen fluid (LAB + SAB). Both SAB and LAB were involved in rumen biohydrogenation of C18:2n-6. SAB fractions performed the full hydrogenation reaction to C18:0 while C18:1 fatty acids, predominantly C18:1t10 and C18:1t11, accumulated in the LAB fractions. SAB and LAB sequence analyses were mainly related to the genera Butyrivibrio and Pseudobutyrivibrio with 12% of the SAB clones closely related to the C18:0 producing B. proteoclasticus branch. In conclusion, this work suggests that I. prostoma and its associated bacteria play no role in C18:2n-6 biohydrogenation, while LAB convert C18:2n-6 to a wide range of C18:1 fatty acids and SAB produce C18:0, the end product of rumen lipid metabolism.

Milk production by the sow is a major factor limiting the growth and survival of her litter. Understanding the process of morphogenesis of the sow’s mammary gland and the factors that regulate mammary development are important for designing successful management tools that may enhance milk production. Primordia of the mammary glands are first observable in the porcine embryo at approximately 23 days of gestation. The glands then progress through a series of morphologically distinct developmental stages such that, at birth, each mammary gland is composed of the teat, an organized fat pad and two separate lactiferous ducts each with a few ducts branching into the fat pad. The glands continue to grow slowly until about 90 days of age when the rate of growth increases significantly. The increased rate of mammary gland growth coincides with the appearance of large ovarian follicles and an increase in circulating estrogen. After puberty, the continued growth of the gland and elongation and branching of the duct system into the fat pad takes place in response to the elevated levels of estrogen occurring as part of the estrous cycles. After conception, parenchymal mass of each gland increases slowly during early pregnancy and then grows increasingly rapidly during the final trimester. This growth is in response to estrogen, progesterone, prolactin and relaxin. Lobuloalveolar development occurs primarily during late pregnancy. By parturition, the fat pad of the mammary gland has been replaced by colostrum-secreting epithelial cells that line the lumen of the alveoli, lobules and small ducts. All mammary glands develop during pregnancy, however, the extent of development is dependent on the location of the mammary gland on the sow’s underline. The mammary glands undergo significant functional differentiation immediately before and after farrowing with the formation of colostrum and the transition through the stages of lactogenesis. Further growth of the glands during lactation is stimulated by milk removal. Individual glands may grow or transiently regress in response to the intensity of suckling during the initial days postpartum. Attempts to enhance milk production by manipulation of mammary development at stages before lactation generally have met with limited success. A more in depth understanding of the processes regulating porcine mammary gland morphogenesis at all stages of development is needed to make further progress.

The present study investigated whether dietary turmeric (Curcuma longa L.) can improve rabbit reproduction, ovarian function, growth, or viability. Female New Zealand White rabbits were either fed a standard diet (n=15) or a diet enriched with 5 g (group E1) or 20 g (group E2) turmeric powder per 100 kg feed mixture (n=16 or 15, respectively). After 295 days, weight gain, conception and kindling rates, pup and mother viability, ovarian macro- and micro-morphometric indices, release of leptin in response to the addition LH, and the release of progesterone, testosterone and leptin by isolated ovarian fragments were analyzed. Dietary turmeric failed to affect ovarian length and weight but did increase the number of primary follicles (E2: 32.5% greater than control group), as well as the diameter of primary (E1: +19.4%, E2: +21.1%), secondary (E2: +41.4%), and tertiary (E1: +97.1%, E2: +205.1%) follicles. Turmeric also increased the number of liveborn (E1: +21.0%) and weaned (E1: +25.0%) pups and decreased the number of stillborn pups (E2: −87.5%) but did not affect weight gain, conception, or kindling rate. Furthermore, dietary turmeric decreased doe mortality during the first reproductive cycle (13.3% in control; 0% in E1; and 6.7% in E2) but not during the second cycle. In vitro, the ovaries of the turmeric-treated rabbits released more progesterone (E1: +85.7%, E2: +90.0%) and less testosterone (E2: −87.0%) and leptin (E2: −29.0%) than the ovaries of control rabbits. Moreover, LH decreased the leptin output of control rabbits but increased that of experimental rabbits. Therefore, it is likely that dietary turmeric improves pup viability and that it could promote rabbit fecundity by either (1) promoting the production of primary ovarian follicles or (2) stimulating the growth of follicles at all stages of folliculogenesis.

Immunocastration or vaccination against boar taint can be used as alternative for surgical castration of male piglets. The vaccine is administrated twice. After the second vaccination (V2), the pigs behave like barrows instead of boars and their feed intake increases which may result in a lower lean meat percentage. The timing of V2 is therefore crucial to find the right balance between the advantages of entire males and barrows. In this study, we evaluated the effect of time post second injection within the advised time frame (4 v. 6 weeks before slaughter) on behaviour, performance, carcass and meat quality of immunocastrated male pigs. In total, 180 animals (hybrid sow×Piétrain): 60 gilts, 60 male pigs vaccinated 6 weeks before slaughter (IM-6) and 60 male pigs vaccinated 4 weeks before slaughter (IM-4), all slaughtered at comparable slaughter weights. After 20 weeks of age, IM-6 showed more inactive behaviour at the expense of playing and aggressive behaviour. Daily feed intake (DFI), daily gain (DG) and feed conversion ratio (FCR) did not differ significantly between IM-6 and IM-4. Gilts had a lower DFI and DG in the late finishing phase and a higher FCR overall compared with both IM groups. Gilts showed a higher lean meat content compared with both IM groups. Earlier vaccination increased dressing percentage, which could partly be explained by the lower weight of the gastrointestinal tract, but not by testes weight. Meat quality traits and palatability did not differ significantly between IM-6 and IM-4. Vaccination of immunocastrates at 6 compared with 4 weeks before slaughter improved the calmness in the stable and the dressing percentage, while maintaining performance and carcass characteristics.

Current European Union legislation will increase the level of disposal of sewage sludge to agricultural land in the next 10 years. This increase may lead to an increase in ingestion, by grazing animals, of herbage with elevated levels of potentially toxic elements (PTEs) derived from sludge adhered to the herbage or sewage sludge-amended soil resulting in the accumulation of PTEs in body tissues, especially the liver and kidney. To assess the possible accumulation of PTEs from soils treated historically with sewage sludge, eight groups of housed weaned lambs were given either dried grass as a sole food (grass control), or diets comprising dried grass (0·9 of total diet dry matter (DM)) and soil (0·1 of total diet DM) from two experimental sites, plots within which had been treated 14 years previously with different quantities of sewage sludge. Soils from the two sites (Cassington and Royston) had contrasting physical characteristics, pH and contents of calcium. The soil from the site at Cassington was slightly acidic (pH 6·0) and had a concentration of calcium of 7·92 g/kg DM whereas the soil from the site at Royston was alkaline (pH 8·0) and had a high concentration of calcium (23·5 g/kg DM). Plots at each site had a range of concentrations of cadmium (Cd) in the soil up to three times the United Kingdom (UK) statutory limit of 3 mg Cd per kg DM. The soils from these two sites were designated control — no amendment with sewage sludge (0·69 mg Cd per kg DM), low (3·55 mg Cd per kg DM), medium (6·63 mg Cd per kg DM) and high (8·82 mg Cd per kg DM; Cassington soil only). Voluntary DM intake of diets by weaned lambs (mean 1436 glday) was not affected significantly by any dietary treatment. The concentrations of Cd in liver increased (P < 0·001) from 0·061 and 0·072 mg/kg DM (Royston and Cassington control, respectively) to 0·218 and 0·403 mg/kg DM (Royston and Cassington medium, respectively) and 0·500 mg/kg DM (Cassington high). The concentrations of Pb in liver increased (P < 0·001) from 0·733 and 0·627 mg/kg DM (Royston and Cassington control, respectively) to 118 and 1·25 mg/kg DM (Royston and Cassington medium, respectively) and 1·18 mg/kg DM (Cassington high). Similar changes were observed for concentrations of Cd and Pb in kidney. A depletion of the concentration of Cu in the liver was observed in all treatments containing soil in the diet. The rate of accumulation of Cd in the liver ranged from 0 to 0·35 μg/g daily tissue DM growth and in the kidney ranged from 0 to 0·44 μg/g daily tissue DM growth. The rate of accumulation of Pb in the liver ranged from 0 to 6·01 μg/g daily tissue DM growth and in the kidney ranged from 0 to 0·63 μg/g daily tissue DM growth. No significant accumulation of PTEs was observed in muscle tissue. It is concluded that the current UK statutory limits for the concentrations ofCd and Pb in soils treated with sewage sludge should be reviewed in the light of these results, though they require confirmation in the grazing situation.

As the number of horses is steadily increasing in Cantabrian less-favoured areas, mostly occupied by nutritionally poor heathland communities, the objective of this research was to study and compare diet selection and performance of crossbred horses and beef cattle (Asturiana de los Valles breed) grazing these areas during the summer. A total of 20 cows (seven lactating their calves and thirteen dry) and 20 mares (eight lactating their foals and twelve dry) were managed during 3 years on a heathland area from June to September and October. The proportion of grass (mostly Pseudarrhenatherum longifolium) and heather (Erica umbellata, E. cinerea and Calluna vulgaris) in the diet selected by cows and mares was estimated in two occasions (July and September) each year using the alkane markers. All animals were weighed at the beginning, middle and end of the summer grazing season. Mares selected heath grasses and rejected heather species more than did the cows (P < 0.001), particularly in early summer (0.85 v. 0.65 herbage proportion in July; 0.63 v. 0.55 in September). Lactating state did not affect diet composition. Mares achieved more favourable (P < 0.001) body weight (BW) changes than cows, but there was also an interaction with season (P < 0.001). From June to August, cows lost BW, being the daily changes (in percentage of initial BW) −0.15%/day in lactating and −0.05%/day in dry cows, whereas both lactating and dry mares gained BW (0.16 and 0.12%/day, respectively). From August to October, lactating cows and mares lost more BW (P < 0.01) compared with their non-lactating counterparts (−0.19 v. −0.10%/day in cows, −0.14 v. −0.05%/day in mares). With regard to the offspring, BW gains between June and August were similar in calves and foals (0.83 and 0.90%/day, respectively), but thereafter calves achieved higher (P < 0.05) BW gains than foals (0.37 v. 0.16%/day). It is concluded that the low nutritive quality of these heathlands restricts, both cattle and horse performance, even during short summer grazing season, being more penalized lactating animals, especially the cows. Although calves were able to maintain acceptable growth rates, foals showed reduced ones during the second half of the grazing season. Other plant communities with better nutritive quality should be provided to assure replenishment of body reserves in dams, and enhance offspring gains to maintain sustainable grazing systems with productive herds of cattle and horses in these heathland areas.

This research was carried out to determine the effects of commercial probiotic (115-Biogallinox) on the colour properties of carcasses and dissected products in broilers. Ross-308 male chicks were given probiotic (P0:0 g/kg, P1:1 g/kg and P2:2 g/kg) containing Saccharomyces cerevisiae for 49 days. At the end of the trial all birds were slaughtered, and pH and skin colour of the carcasses were determined at various times during the first 24 h (1, 3, 7, 12, 17 and 24 h). After dissection, breasts and drumsticks were divided into two groups for vacuum packaging and aerobic packaging. Packaged breasts and drumsticks were stored at 3 ± 0.5°C for 12 days. During the storage period, the colours of breast meat, drumstick meat and drumstick skin were determined.

pH values of carcasses decreased (P < 0.01) over the 24-h period post mortem. The pH values of the P1 group were lower than the P0 and P2 groups (P < 0.01). L*, a* and b* values increased during the 24-h period and the P0 group had lower a* values than the P1 and P2 groups (P < 0.05). The use of probiotic in the broiler diet had no effect on L*, a* and b* values of breast and drumstick muscle. The L* and a* values of breast muscles were lower than drumstick muscles (P < 0.05). The values of b* in aerobic packaged breasts and drumsticks were higher than when vacuum packaged (P < 0.01). L* and b* values were also affected by storage period. While the L* and b* values of drumstick skin were higher than of drumstick meat, a* values in drumstick meat were higher (P < 0.05). The packaging had no effect on drumstick colour values (drumstick meat and drumstick skin) and L* and b* values decreased during the storage period.

Cloning has advanced through the recent demonstrations that it is feasible to produce, in principle and with significant effort, an unlimited number of individuals of identical genotype from differentiated cell lines that have been frozen and thawed. These advances have been based upon understanding the importance of interactions between the stage of the cell cycle of both the oocyte and donor cell for the success of the nuclear transfer. Whilst the impact of the biological advance is immense for biomedicai applications, the significance is less clear for livestock breeding. In our view the scientific issues for breeding programmes lie in whether clones can increase genetic progress without a cost to biodiversity. Biodiversity within a species may be categorized as: (i) betvjeen-breed variation; (ix) genetic variation among parents within breeds; (iii) genetic variation among individuals within a farm; and (iv) allelic variation within an individual. In the face of a rapid global decline in breed diversity, cloning, in particular cloning of adults, may be an important route to protect biodiversity since it may allow far more genetic variation to be made available for new breed development in the future than is practicable at present. For variation among parents, the judicious use of clones may give significantly faster rates of progress without increasing the rate of loss of genetic variation and furthermore can help improve traits associated with health and welfare which are at present less tractable than, say, milk yield. Local diversity within a farm may be greatly affected if cloning is utilized to disseminate genetic progress widely and more answers are required on the importance of genetic variation within any one locality either in buffering diseases or ameliorating other management problems. Experience from clonal forestry can provide some indications but now there are models capable of answering this question directly in livestock. Allelic variation within individuals per se is not generally advantageous but at loci where it is identified to he beneficial, the use of cloning may exploit it more widely.

1. Three pigs prepared with re-entrant cannulae in the proximal duodenum and terminal ileum were used to study flow rate of nitrogen, and digestion and absorption of dry matter, nitrogen, gross energy and starch. The pigs were given a semi-purified diet, a hard wheat diet and a soft wheat diet. These were approximately isonitrogenous.

2. Nitrogen content of insoluble dry matter of duodenal digesta was much higher on the semi-purified diet than on the wheat-based diets.

3. Apparent digestibilities of dry matter, energy and nitrogen in the small intestine were in the order semi-purified diet > hard wheat > soft wheat although differences were not statistically significant. Similar results were obtained for total digestibility of these components.

4. Absorption of most amino acids from the small intestine was higher for casein in the semi-purified diet than for wheat protein. Significantly more lysine, arginine, isoleucine and tyrosine were absorbed from hard than from soft wheat.

5. With all diets there was almost complete digestion of starch in the small intestine.

6. There was little digestion of nutrients in the large intestine, and thus digestibilities calculated from faecal analyses showed similar trends to those calculated from analyses of digesta from the terminal ileum. Most values compared favourably with those reported elsewhere for digestibilities of amino acids in wheat.

7. It was concluded that casein was superior to the wheat proteins but that protein of hard wheat was of better quality than that of soft wheat when evaluated by ileal recovery of animo acids, due largely to a greater absorption of lysine.