The extent to which genetic selection to change the concentration of copper (Cu) in plasma also affected the retention of Cu in the liver was assessed in three experiments. In each, the concentration of Cu was measured in samples of liver (taken by biopsy) and of plasma from female sheep of lines selected from a Scottish Blackface × Welsh Mountain population (which had previously been interbred for several generations) for high and low plasma Cu levels (high line and low line) and from purebred Scottish Blackface and Welsh Mountain females.

The concentration of Cu in the liver and plasma was found to be consistently greater in high-line and Welsh Mountain than in low-line and Scottish Blackface females (P < 0·01) in the first experiment in which grazing animals were sampled at both 6 and 10 months of age and in the second, where sampling' was at 6 months only. Mean Cu concentrations in the liver ranged from 13 to 115 mg/kg dry matter (DM) and the correlations with those in plasma varied from 0·28 to 0·53 (all P < 0·05) and was highest when the concentration of Cu in the liver was lowest. The correlation between the concentrations of Cu in liver at different ages was 0·57 (P < 0·05).

In the third experiment, 10-month-old high- and low-line females were given complete diets containing either 5, 10, 22 or 28 mg Cu per kg DM for 12 weeks. Liver samples were obtained at the beginning and end of this period and blood samples were taken every 3 weeks. The concentration of Cu in the liver was greater in high- than in low-line sheep on all diets and increased linearly with the Cu concentration of the diet but at a greater rate in the high line. At the end, the high line had significantly greater concentrations of Cu in plasma on the 5 and 10 mg Cu per kg DM diets.

The experiments showed that high-line females retained more Cu in the liver than low-line females. It is most likely that this was caused by a positive genetic correlation between concentration of Cu in plasma and the efficiency of absorption of Cu.

One of the benefits of the genomics revolution for animal production will be knowledge of genes that can be used to select more profitable livestock. Although it is possible to use genetic markers linked to genes of economic importance, tests for the genes themselves will be much more successful. Consequently finding genes of economic importance to livestock will be a major research aim for the future. Most traits of economic importance are quantitative traits affected by many genes. Mutations at many genes (e.g. 500) and at many positions within a gene (e.g. 1000 coding and non-coding bases) can affect a typical quantitative trait. The effect of these mutations on phenotype is usually small (e.g. 0·1 standard deviation) but occasionally large. Many mutations are lost from the population through genetic drift and selection, so that polymorphisms exist at only a subset of the relevant genes (e.g. 100 genes). Finding these genes, that have relatively small effects, is more difficult than finding genes for a classical Mendellian trait but, as the genomic tools become more powerful, it is becoming feasible and some successes have already occurred. The standard approach is to map a quantitative trait loci (QTL) to a chromosome region using linkage and linkage disequilibrium. Then test polymorphisms in positional candidate genes for an effect on the trait. Tools such as genomic sequence, EST collections and comparative maps make this approach feasible. Candidate genes can be selected based on functional data such as gene expression obtained from microarrays. At present the gain in rate of genetic improvement from use of DNA-based tests for QTL is small, because selection without them is already quite accurate, not enough QTL have been identified and genotyping is too expensive. However, in the future, with many QTL identified and inexpensive genotyping combined with decreased generation intervals, large gains are possible.

The cover comb has been developed in New Zealand as a means of increasing residual fleece depth after shearing and so increasing the resistance of shorn sheep to cold stress.

The effects of shearing by cover comb and standard comb were studied over 2 days pre-shearing and 10 days post-shearing in eight pairs of non-pregnant, non-lactating 2-year-old ewes. Animals were housed and given a maintenance level of chaffed lucerne hay. One member of each pair was shorn with a cover comb, the other with a standard comb. Each pair was exposed to ‘cold plus wind’ (7°C ambient temperature, 7 km/h air movement) followed by ‘cold plus wind plus rain’ (10°C ambient temperature, 7km/h air movement, wetting at a rate equivalent to 25 mm/h rain from overhead sprinklers) in a calorimetry chamber on days S –3, S –2, SO (day of shearing), S2, S6 and S10. Heat production immediately after shearing (SO) was proportionately 0·22 greater in ewes shorn by the standard comb under conditions of ‘cold plus wind’ and 0·38 greater under conditions of ‘cold plus wind plus rain’ than in their cover comb-shorn cohorts. Circulating concentrations of non-esterifiedfatty acids were substantially elevated on the day of shearing and 2 days thereafter in ewes shorn by the standard comb, indicating increased rates of body fat mobilization to support heat production in these ewes compared with those shorn by the cover comb. This was reflected in a 1·4 kg weight loss in the standard comb-shorn ewes compared with a 0·4 kg live-weight gain in the cover comb-shorn group over the 10 days of the experiment. It was concluded that use of a cover comb will significantly reduce the risk of death from hypothermia in sheep shorn during winter and spring, and should facilitate an increase in the productivity of animals by allowing a greater proportion of food energy to be used for productive purposes.

Incorporation of food intake into breeding objectives for ruminants is often difficult because the relevant genetic parameters are unavailable. A non-statistical approach to estimating the genetic relationships between food costs and genetic changes in growth and body composition traits was therefore developed.

Equations which predict additional food requirements associated with genetic changes in growth and body composition traits are derived from an interspecies growth model. In the growth model, a genotype is mainly described according to its expected mature weights of protein, lipid and a composition trait of interest in the empty body under non-limiting conditions. Other model parameters describe the expected growth of the animal in a specific environment.

An example is shown for beef cattle in the United Kingdom, where increases in carcass weight by 1 kg and carcass subcutaneous fat proportion by 0·01 result in increases in food costs by £0·97 and £7·34 respectively for a production system where animals are given an intensive silage/concentrate diet, are slaughtered at 305 kg and have a commercial fat grade 4L. A strong dependence of the results on the type of production system, especially the degree of maturity in protein at slaughter, is demonstrated.

The model is easily adapted to other breeds and ruminant species. The approach is recommended for incorporating food intake into breeding objectives for ruminants in situations where reliable estimates of the necessary genetic parameters for a more conventional specification of the breeding objective are unavailable.

In horses, successful in vitro fertilization procedures are limited by our inability to consistently mature equine oocytes by in vitro methods. Growth hormone (GH) is an important regulator of female reproduction in mammals, playing an important role in ovarian function, follicular growth and steroidogenesis. The objectives of this research were to investigate: the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I) on the in vitro maturation (IVM) of equine oocytes, and the effects of eGH in addition to estradiol (E2), gonadotropins (FSH and LH) and fetal calf serum (FCS) on IVM. We also evaluated the cytoskeleton organization of equine oocytes after IVM with eGH. Equine oocytes were aspirated from follicles <30 mm in diameter and matured for 30 h at 38.5°C in air with 5% CO2. In experiment 1, selected cumulus–oocyte complexes (COCs) were randomly allocated as follows: (a) control (no additives); (b) 400 ng/ml eGH; (c) 200 ng/ml IGF-I; (d) eGH + IGF-I; and (e) eGH + IGF-I + 200 ng/ml anti-IGF-I. In addition to these treatment groups, we also added 1 μg/ml E2, 5 IU/ml FSH, 10 IU/ml LH and 10% FCS in vitro (experiment 2). Oocytes were stained with markers for microtubules (anti-α-tubulin antibody), microfilaments (AlexaFluor 488 Phalloidin) and chromatin (TO-PRO3-iodide) and assessed via confocal microscopy. No difference was observed when eGH and IGF-I was added into our IVM system. However, following incubation with eGH alone (40%) and eGH, E2, gonadotropins and FCS (36.6%) oocytes were classified as mature v. 17.6% of oocytes in the control group (P < 0.05). Matured equine oocytes showed that a thin network of filaments concentrated within the oocyte cortex and microtubules at the metaphase spindle showed a symmetrical barrel-shaped structure, with chromosomes aligned along its midline. We conclude that the use of E2, gonadotropins and FCS in the presence of eGH increases the number of oocytes reaching oocyte competence.

An experiment was conducted to determine if molasses could be successfully used to administer dotriacontane (C32) and hexatriacontane (C36) n-alkane markers to steers and to compare this method with a commercially available intra-ruminal controlled release device (CRD). The experiment was conducted over two similar periods (runs) using 24 Brahman crossbred steers in each run to study the effect of marker delivery methods and tropical grass hay diets in a randomized complete block design with three replicates. All steers were housed individually in partially covered pens, received one of two buffel-grass hays (B20: 20-week regrowth; 0·72 g nitrogen (N) per 100 g and B8: 8-week regrowth; 1·11 g N per 100 g) and one of four marker delivery treatments (control: no marker; 200 mg/day of C32 and C36 n-alkanes from a CRD or offered three times (Ms ✕ 3) or five times (Ms ✕ 5) a day in molasses). Voluntary intake (VI) and dry matter digestibility (DMD) for diets differed (P < 0·001) with B8 greater than B20. There was no difference among marker treatments for VI but the control treatment had greater, unexplained and possibly spurious, DMD than the Ms ✕ 3 marker treatment. Although the recovery of n-alkanes was variable (0·84 to 1·05) adjacent odd- and even-chain n-alkanes were similar with no differences (P > 0·05) due to marker treatment or diet. The CRD supplied a consistent marker dose between 6 and 18 days after insertion. Deviation from the 24-h mean faecal concentration seldom varied more than 0·03 for the individual markers and 0·05 for C31/C32 and C33/C32 ratios for all treatments. Over all the n-alkanes studied, the between-day variation was less than the within-day variation. For instance, the average of subsamples taken at 06:00 h and 18:00 h was within proportionately 0·05 of the 10-day mean concentration for 0·38 and 0·25 of records for C32 and C36 markers, respectively. It was concluded that molasses containing C32 and C36 n-alkane markers and given either three or five times daily was as accurate as the commercial CRD in administering n-alkane markers to steers and provides a method of delivering n-alkanes over an extended period in grazing studies.

Peripheral concentrations of melatonin in the neonatal mammal are low and the diurnal rhythm is not apparent during the first days or weeks of life. Maternal milk provides a rhythmic although low source of melatonin to the newborn. Diurnal rhythm of serum melatonin was monitored in Friesian calves from birth to 4 weeks of age. Some of the calves under 1 week of age had no clear nocturnal elevation of serum concentrations of melatonin. Thereafter the nocturnal melatonin elevation was apparent in all calves and of the same amplitude as in adult cattle. The effect of oral intake of night-time milk or milk supplemented with low doses of synthetic melatonin was studied during day-time in a group of Ayrshire calves aged 1 to 5 weeks. Two and a half or 3 litres of night-time milk with a mean melatonin concentration of 40 pg/ml, providing 01 to 012 μg melatonin, did not cause any change in the day-time serum concentrations of melatonin, neither did addition of melatonin in doses up to 10 μg per animal. Only the highest dose of melatonin 200 μg in 2 l of milk (01 μg/ml) caused an elevation of day-time serum concentrations of melatonin. These studies show that the pineal gland of a very youg calf is functional and that the concentration of melatonin in blood does not reflect the concentration in milk at the time of feeding. The presence of melatonin in milk suggests, however, its potential significance for the neonate.

Halothane positive and negative selection lines were established to estimate the effects of the halothane gene on performance in British Landrace pigs. Incidences of positive reaction diverged from 0·12 in the foundation generation to 0·93 in the positive and to 0·02 in the negative line in generation 4. Differences in litter productivity as a trait of the dam were estimated from a total of 399 positive × positive and negative × negative parity 1 and 2 matings in generations 1 to 4.

Compared with negative contemporaries, positive females showed non-significant reductions in litter size at birth (−0·10, s.e. 0·26) and at 42 days (−0·28, s.e. 0·26), accompanied by significant reductions in average piglet weights at birth (−0·11, s.e. 0·02 kg) and 42 days (−0·4, s.e. 0·2 kg). There were no differences in conception rate or adult live weights. A subsample of 69 parity 2 and 3 sows slaughtered 30 days after mating showed no significant difference in ovulation rate or embryo survival, but for positive dams the length of embryos was significantly reduced (−3·1, s.e. 1·1 mm).

The study suggests that the principal effect of the halothane gene was in reducing foetal growth rather than litter size. However, the phenotypic difference is expected to under-estimate the genetic difference between homozygotes, and it was not possible to distinguish the effects of dam and offspring genotypes. The present economic loss of roughly £4·70 per positive litter would be unlikely to justify elimination of the gene from a purebred maternal Landrace herd.

Increase of fat cells (FCs) in adipose tissue is attributed to proliferation of preadipocytes or immature adipocytes in the early stage, as well as adipogenic differentiation in the later stage of adipose development. Although both events are involved in the FC increase, they are contrary to each other, because the former requires cell cycle activity, whereas the latter requires cell cycle withdrawal. Therefore, appropriate regulation of cell cycle inhibition is critical to adipogenesis. In order to explore the important cell cycle inhibitors and study their expression in adipogenesis, we adopted a strategy combining the Gene Expression Omnibus (GEO) database available on the NCBI website and the results of quantitative real-time PCR (qPCR) data in porcine adipose tissue. Three cell cycle inhibitors – cyclin G2 (CCNG2), cyclin-dependent kinase inhibitor 2C (CDKN2C) and peripheral myelin protein (PMP22) – were selected for study because they are relatively highly expressed in adipose tissue compared with muscle, heart, lung, liver and kidney in humans and mice based on two GEO DataSets (GDS596 and GDS3142). In the latter analysis, they were found to be more highly expressed in differentiating/ed preadipocytes than in undifferentiated preadipocytes in human and mice as shown respectively by GDS2366 and GDS2743. In addition, GDS2659 also suggested increasing expression of the three cell cycle inhibitors during differentiation of 3T3-L1 cells. Further study with qPCR in Landrace pigs did not confirm the high expression of these genes in adipose tissue compared with other tissues in market-age pigs, but confirmed higher expression of these genes in FCs than in the stromal vascular fraction, as well as increasing expression of these genes during in vitro adipogenic differentiation and in vivo development of adipose tissue. Moreover, the relatively high expression of CCNG2 in adipose tissue of market-age pigs and increasing expression during development of adipose tissue was also confirmed at the protein level by western blot analysis. Based on the analysis of the GEO DataSets and results of qPCR and Western blotting we conclude that all three cell cycle inhibitors may inhibit adipocyte proliferation, but promote adipocyte differentiation and hold a differentiated state by inducing and maintaining cell cycle inhibition. Therefore, their expression in adipose tissue is positively correlated with age and mature FC number. By regulating the expression of these genes, we may be able to control FC number, and, thus, reduce excessive fat tissue in animals and humans.

The objective of this study was to evaluate the effects of two sublethal doses (4 and 20 mg/kg live weight (LW); every other day) of gossypol on semen and hormonal characteristics of male rabbits. The experiment lasted 16 weeks and included two periods: a treatment period (first 8 weeks) where the animals were given the test materials, and a recovery period (second 8 weeks) where drugs were withdrawn. Results showed that LW and respiration rate (RR) decreased ( P<0·05) among animals that received gossypol, while rectal temperature increased ( P<0·05). Animals in gossypol treatment groups had decreased ( P<0·05) blood plasma levels of tri-iodothyronine (T3) and testosterone. This was accompanied by reductions ( P<0·05) in sperm concentration, total sperm output, percentage incidence of forward motility, total functional sperm fraction and semen initial fructose concentration. Gossypol however increased ( P<0·05) reaction time (i.e. decreased libido), percentages of dead sperm and abnormal sperm (AbSp) and altered acrosomes. Estimated weights of testes and semen ejaculate volume increased ( P<0·05) possibly due to increased water retention. Values of LW, RR, AbSp, and blood plasma T3 and testosterone returned to control levels after withdrawal of gossypol, while the effect of this drug on other parameters continued during the recovery period.

Thirty crossbreed steer calves were randomly assigned to one of three feedlot treatment groups to evaluate the effectiveness of diatomaceous earth (DE) as an anthelmintic treatment and its effect on subsequent growth performance. Steers were adapted to a cereal-based diet for 15 days on the farm of origin and given an additional 21 days to adjust to the feedlot diet. Calves had not been dewormed prior to starting the study. On day 0 (2 January 1996) the positive control group of steers (CONV; no. = 11) was given 10 mg/kg of albendazole, a second group began receiving (on day 2) 0·3 kg of diatomaceous earth (DE; no. = 9) mixed daily with their food for 46 days and the negative control group (CTRL, no. = 9) received no anthelmintic treatment. Rectal faecal samples were collected upon arrival at the feedlot and the resulting egg counts showed that all steers were positive for nematodes and coccidia. Faecal samples were collected on days 0, 15, 28 and every 28 days thereafter to determine faecal egg counts. The last sample was taken on the day of slaughter. On day 0, the average count for all calves was over 70 eggs per g faeces (epg) for trichostrongyle type eggs; counts for Nematodirus sp., Strongyloides sp., Trichuris sp. and Capillaria sp. were negligible. CTRL and DE steers had higher parasite levels than CONV steers during the 1st (P < 0·01) and 2nd months (P < 0·05) after treatment. Egg counts for CTRL and DE groups decreased in March and none of the groups differed (P > 0·05) significantly for the remainder of the study. Coccidia levels decreased over time similarly for all groups. Offering 20 g DE per kg food intake for 46 days to beef steers on a high cereal -based diet had no effect (P > 0·05) on body weight, average daily gain, dry-matter intake, food conversion or days on food compared with the untreated control steers. Cumulative food conversion during the first 2 months was better for CONV than for DE and CTRL steers (P < 0·01) but did not differ between the latter two groups (P > 0·05). Cumulative food conversion for the rest of the study remained the same for all groups (P > 0·05). CONV calves required fewer days on food than DE calves (P < 0·05) but about the same number as CTRL calves (P > 0·10). Steers in the DE group required a similar number of days on food (230·22 ± 7·86 days) to reach target end points as CTRL steers (218·75 ± 8·34 days; P > 0·05) but more days than CONV calves (201·64 ± 7·11 days; P > 0·05).

Channel catfish raised in the southern United States require two growing seasons to reach market size. Growing seasons are separated by a cool period of about 3 months when feed intake and growth are greatly reduced. A cool-weather feeding strategy to improve feed intake, growth or health of catfish might improve survival and reduce the time needed to achieve market size. We conducted a feeding trial with channel catfish at a suboptimal temperature (15°C) to determine the effects of supplementing diets with either a dairy/yeast prebiotic or flaxseed oil (high in 18:3n-3) compared with a control with soybean oil (high in 18:2n-6). The trial was conducted in recirculating systems with 1140-l tanks containing 100 fish each (mean initial weight 61.4 g±0.43 s.e.m.). A 28%-protein basal diet was supplemented with 20 g/kg cellulose and 20 g/kg soybean oil (SBO, control), 20 g/kg cellulose and 20 g/kg flaxseed oil (FLAX) or 20 g/kg of a dairy/yeast prebiotic and 20 g/kg soybean oil (PREB). Fish were fed once daily to satiation and weighed every 3 weeks to track growth. Hematology, non-specific immune responses, proximate and fatty acid composition of muscle were determined to assess diet effects. Catfish-fed FLAX or PREB had higher weight gain, feed consumption and lysozyme activity than fish fed SBO. Total n-3 fatty acids in muscle were higher in fish fed SBO or FLAX than those fed PREB. Total n-6 long-chain polyunsaturated acids were higher in muscle of fish fed PREB than those fed SBO. Fatty acids in the PREB and SBO diets were similar, so the PREB appeared to increase elongation and desaturation of n-6 fatty acids in muscle. Flaxseed oil and the dairy/yeast prebiotic both have potential to increase catfish performance at a low temperature.

We recently showed that the mRNA expression of genes encoding for specific nutrient sensing receptors, namely the free fatty acid receptors (FFAR) 1, 2, 3, and the hydroxycarboxylic acid receptor (HCAR) 2, undergo characteristic changes during the transition from late pregnancy to lactation in certain adipose tissues (AT) of dairy cows. We hypothesised that divergent energy intake achieved by feeding diets with either high or low portions of concentrate (60% v. 30% concentrate on a dry matter basis) will alter the mRNA expression of FFAR 1, 2, 3, as well as HCAR2 in subcutaneous (SCAT) and retroperitoneal AT (RPAT) of dairy cows in the first 3 weeks postpartum (p.p.). For this purpose, 20 multiparous German Holstein cows were allocated to either the high concentrate ration (HC, n=10) or the low concentrate ration (LC, n=10) from day 1 to 21 p.p. Serum samples and biopsies of SCAT (tail head) and RPAT (above the peritoneum) were obtained at day −21, 1 and 21 relative to parturition. The mRNA abundances were measured by quantitative PCR. The concentrations of short-chain fatty acid (SCFA) in serum were measured by gas chromatography-flame ionisation detector. The FFAR1 and FFAR2 mRNA abundance in RPAT was higher at day −21 compared to day 1. At day 21 p.p. the FFAR2 mRNA abundance was 2.5-fold higher in RPAT of the LC animals compared to the HC cows. The FFAR3 mRNA abundance tended to lower values in SCAT of the LC group at day 21. The HCAR2 mRNA abundance was neither affected by time nor by feeding in both AT. On day 21 p.p. the HC group had 1.7-fold greater serum concentrations of propionic acid and lower concentrations of acetic acid (trend: 1.2-fold lower) compared with the LC group. Positive correlations between the mRNA abundance of HCAR2 and peroxisome proliferator-activated receptor γ-2 (PPARG2) indicate a link between HCAR2 and PPARG2 in both AT. We observed an inverse regulation of FFAR2 and FFAR3 expression over time and both receptors also showed an inverse mRNA abundance as induced by different portions of concentrate. Thus, indicating divergent nutrient sensing of both receptors in AT during the transition period. We propose that the different manifestation of negative EB in both groups at day 21 after parturition affect at least FFAR2 expression in RPAT.

Twenty-four British Friesian dairy cattle in their first lactation were used in a change-over design experiment with four periods, each of 4 weeks duration. The aim of the experiment was to examine the effects of varying both concentrate crude-protein concentration and the proportions of concentrates and grass silage in the diet on milk yield and composition. Twelve treatments were examined in a 3 × 4 factorial arrangement. Concentrates containing four levels of crude protein (CP), ranging from 120 to 206 g/kg fresh weight were offered in diets containing either 400, 500 or 600 g concentrates per kg dry-matter (DM) intake. The grass silage offered as the basal forage had a DM concentration of 214 g/kg and a digestible organic matter concentration of 682 g/kg DM.

Milk yields (kg/day) for cows offered diets containing 400, 500 and 600 g concentrates per kg DM were 17·2, 18·1 and 18·3 respectively; and 17·4, 17·6, 18·0 and 18·4 for cows offered diets with concentrates containing 120, 147, 176 and 206 g CP per kg fresh weight respectively (pooled s.e. 0·13). Increasing either the proportion of concentrates in the diet or the CP concentration of the concentrates did not significantly affect milk fat concentration, but did increase milk protein concentration.

There was a trend towards a greater milk-yield response to protein supplementation with low- rather than high-concentrate diets, although it appears that this trend may only be apparent in situations where total food intake is restricted.

Fermented feeds are being considered as practical alternatives to antimicrobial growth promoters (AGP) supplemented in nursery pig diets. This study aimed to investigate health-promoting effects of fermented barley in weaned pigs challenged with Escherichia coli K88 +. A total of 37 piglets were weaned at 21 ± 1 day of age (6.41 ± 0.47 kg of BW) and assigned to either of the following five treatment groups: (1) unchallenged control (UCC; n = 7), (2) challenged control (CC; n = 7), (3) AGP (CC + 0.1% AGP; n = 7), (4) Ferm1 (challenged and fed homofermentative Lactobacillus plantarum (Homo)-fermented barley; n = 8) and (5) Ferm2 (challenged and fed heterofermentative L. buchneri (Hetero)-fermented barley; n = 8). The control diet included unfermented barley. Barley was fermented with either Homo or Hetero for 90 days under anaerobic conditions. On day 10, all pigs except those in UCC group were orally inoculated with E. coli K88 + (6 × 109 colony forming units/ml). The pre-planned orthogonal test was performed to compare (1) UCC and CC, (2) CC and AGP, (3) CC and Ferm1 + Ferm2, as well as (4) Ferm1 and Ferm2. Challenged control pigs showed shorter (P < 0.05) villus height (VH) in the duodenum and deeper (P < 0.05) crypt depth (CD) in the jejunum than UCC pigs. The AGP group had higher (P < 0.05) VH and lower (P < 0.05) IL-6 gene expression in the jejunum compared with CC group. Compared to CC, Ferm1 and Ferm2 had decreased (P < 0.05) CD in the duodenum, IL-6 gene expression in the jejunum and rectal temperature at 24 h post-challenge. Pigs fed fermented barley diets showed greater (P < 0.05) faecal abundance of Clostridium Cluster IV and Lactobacilli than those fed UCC diet. Ferm2-fed pigs showed lower (P < 0.05) concentrations of band cells, eosinophils and lymphocytes at 6, 24 and 48 h after challenge, respectively, and lower (P < 0.05) faecal abundance of Enterobacteriaceae 24 h after challenge than the Ferm1-fed pigs. In conclusion, the substitution of unfermented barley with fermented barley in a nursery diet showed similar results as those shown by AGP supplementation in terms of enhancing the intestinal morphology and modulating faecal microbiota composition, as well as down-regulating the pro-inflammatory cytokines; therefore, fermented barley can be a possible nutritional strategy for managing nursery pigs fed diets without in-feed AGP.

1. Eight Ayrshire milk cows were grazed for four 3-week periods from July to October 1957 in a balanced sequence on two strip-grazed and two free-grazed paddocks, each of two acres. Feed intake and digestibility were estimated by the chromic-oxide faecal-nitrogen method.

2. There was no significant difference in average feed digestibility between the treatments. Free grazing cows ate 30·4 lb. dry matter per day and strip grazing cows 28·9 lb. The difference was just significant (p<0·05). There was no significant difference in milk yield, live-weight or live-weight gain per cow.

3. Total feed output per acre was 11% greater on strip grazing when measured by utilised starch equivalent but only 1 % greater when measured by estimated feed consumption. The data suggest that strip-grazed cattle needed less energy for grazing.

4. The results are discussed with reference to their accuracy, their implications on grazing management and their correspondence with estimates of food requirements based on indoor feeding standards.

In endangered and local pig breeds of small population sizes, production has to focus on alternative niche markets with an emphasis on specific product and meat quality traits to achieve economic competiveness. For designing breeding strategies on meat quality, an adequate performance testing scheme focussing on phenotyped selection candidates is required. For the endangered German pig breed ‘Bunte Bentheimer’ (BB), no breeding program has been designed until now, and no performance testing scheme has been implemented. For local breeds, mainly reared in small-scale production systems, a performance test based on in vivo indicator traits might be a promising alternative in order to increase genetic gain for meat quality traits. Hence, the main objective of this study was to design and evaluate breeding strategies for the improvement of meat quality within the BB breed using in vivo indicator traits and genetic markers. The in vivo indicator trait was backfat thickness measured by ultrasound (BFiv), and genetic markers were allele variants at the ryanodine receptor 1 (RYR1) locus. In total, 1116 records of production and meat quality traits were collected, including 613 in vivo ultrasound measurements and 713 carcass and meat quality records. Additionally, 700 pigs were genotyped at the RYR1 locus. Data were used (1) to estimate genetic (co)variance components for production and meat quality traits, (2) to estimate allele substitution effects at the RYR1 locus using a selective genotyping approach and (3) to evaluate breeding strategies on meat quality by combining results from quantitative-genetic and molecular-genetic approaches. Heritability for the production trait BFiv was 0.27, and 0.48 for backfat thickness measured on carcass. Estimated heritabilities for meat quality traits ranged from 0.14 for meat brightness to 0.78 for the intramuscular fat content (IMF). Genetic correlations between BFiv and IMF were higher than estimates based on carcass backfat measurements (0.39 v. 0.25). The presence of the unfavorable n allele was associated with increased electric conductivity, paler meat and higher drip loss. The allele substitution effect on IMF was unfavorable, indicating lower IMF when the n allele is present. A breeding strategy including the phenotype (BFiv) combined with genetic marker information at the RYR1 locus from the selection candidate, resulted in a 20% increase in accuracy and selection response when compared with a breeding strategy without genetic marker information.

Data are provided from four Kenya ranches relating to seasonality of breeding, age at first parturition, parturition interval, sex ratio, gestation period and the early survival of young in one-humped camels. A total of 799 births was recorded. Births occurred throughout the year with no marked peak, there being no significant correlation of conception with rainfall. Age at first parturition (no. = 37) was 54·3 months. Parturition interval (no. = 460) was 20·2 months and was significantly affected by the random effects of the dam as well as by the fixed effects of the herd and the survival of the previous young. The sex ratio at birth was 1·06 males to 1·00 female. Gestation period was 377·1 days, and was not significantly affected by any of herd, month of conception, sex of young or age of animal. Abortions amounted to 11·6% of all births with the total of pre-weaning losses (including abortions) being 25·7%. Improving familiarity of the owners with the animals and better management could lead to considerable increases in performance.

Reducing dietary CP content is an effective approach to reduce animal nitrogen excretion and save protein feed resources. However, it is not clear how reducing dietary CP content affects the nutrient digestion and absorption in the gut of ruminants, therefore it is difficult to accurately determine how much reduction in dietary CP content is appropriate. This study was conducted to investigate the effects of reduced dietary CP content on N balance, intestinal nutrient digestion and absorption, and rumen microbiota in growing goats. To determine N balance, 18 growing wether goats (25.0 ± 0.5 kg) were randomly assigned to one of three diets: 13.0% (control), 11.5% and 10.0% CP. Another 18 growing wether goats (25.0 ± 0.5 kg) were surgically fitted with ruminal, proximate duodenal, and terminal ileal fistulae and were randomly assigned to one of the three diets to investigate intestinal amino acid (AA) absorption and rumen microbiota. The results showed that fecal and urinary N excretion of goats fed diets containing 11.5% and 10.0% CP were lower than those of goats fed the control diet (P < 0.05). When compared with goats fed the control diet, N retention was decreased and apparent N digestibility in the entire gastrointestinal tract was increased in goats fed the 10% CP diet (P < 0.05). When compared with goats fed the control diet, the duodenal flow of lysine, tryptophan and phenylalanine was decreased in goats fed the 11.5% CP diet (P < 0.05) and that of lysine, methionine, tryptophan, phenylalanine, leucine, glutamic acid, tyrosine, essential AAs (EAAs) and total AAs (TAAs) was decreased in goats fed the 10.0% CP diet (P < 0.05). When compared with goats fed the control diet, the apparent absorption of TAAs in the small intestine was increased in goats fed the 11.5% CP diet (P < 0.05) and that of isoleucine, serine, cysteine, EAAs, non-essential AAs, and TAAs in the small intestine was increased in goats fed the 10.0% CP diet (P < 0.05). When compared with goats fed the control diet, the relative richness of Bacteroidetes and Fibrobacteres was increased and that of Proteobacteria and Synergistetes was decreased in the rumen of goats fed a diet with 10.0% CP. In conclusion, reducing dietary CP content reduced N excretion and increased nutrient utilization by improving rumen fermentation, enhancing nutrient digestion and absorption, and altering rumen microbiota in growing goats.

Water scarcity is among the main challenges making vulnerable the livestock farming systems in drylands. The water footprint (WF) indicator was proposed as a metric to measure the impacts of livestock production on freshwater resources. Therefore, this study aimed to assess water use in five different Tunisian sheep production systems using the Water Footprint Network methodology. The primary data were obtained from 1050 sheep farms located in 13 Tunisian provinces. A multivariate analysis was performed to characterize the different farming systems. A validation step of the WF modeled values of sheep meat was conducted in 12 sheep farms belonging to two different farming systems. This was done through year-round monitoring of on-farm practices using water metres and recording equipment’s taking into account the direct and indirect water use. The typology analysis came up with five sheep farming systems that are the mixed sheep-cereal (MSC), the agro-sylvo-pastoral (ASP), the agro-pastoral (AP), the extensive agro-pastoral (EAP) and the mixed sheep-olive tree farming systems. The WF of sheep meat produced under the target farming systems ranged from 8654 to 13 056 l/kg live weight. The evaluation of WF of five different sheep production systems figured out that sheep raised under the EAP farming system had the greatest WF per ton of live animal. However, the ASP farming system exhibited the lowest WF. Water used to grow feedstuffs for sheep production accounts for 98% of the total WF of sheep. The green WF accounts for more than 92% of the total WF in all farming systems. Results of monitoring water use at farm scale show that the modeled values of WF are overestimated by an average of 23.3% and 24.1% for the selected farms assigned to the MSC and AP farming systems, respectively. Water use for sheep production is high in most of the Tunisian farms. Therefore, the general assumption that ‘meat production is a driver of water scarcity’ is supported and should be considered as an important focal point in agricultural and water policies. Particular attention should be given to forage crops with low WFs and high contribution to dry matter to provide ration with low WF. The efficient use of green water along the meat value chain is essential to minimize the depletion of blue water resources and to reduce the economic dependency on virtual water through the import of feedstuffs.