The objectives of this study were to evaluate the effects of Burdizzo castration and abrupt weaning on the behaviour, blood traits and performance of beef calves when weaning was conducted concurrently or consecutively to castration. In total, 64 male beef calves aged between 6 and 7 months were assigned to a 2×2 factorial design with the following treatment groups (n=16 animals per treatment): (1) castrated and concurrently weaned in week 0 (CAS-WEA); (2) castrated in week 0 and weaned in week 4 (CAS-CON); (3) bulls weaned in week 0 (BUL-WEA); and (4) bulls weaned in week 4 (BUL-CON). The behaviour of the calves was observed for 3 days following weaning. Blood was collected weekly from weeks 0 to 5 and analysed for the acute-phase protein haptoglobin, and neutrophil and lymphocyte percentages. BW was recorded weekly from weeks 0 to 7. Animals were slaughtered at 17 months and weight, dressing percentage and carcass classifications were recorded. On day 1 after weaning, the number of vocalizations (calls/10 min) was higher in BUL-WEA (7.2) and CAS-WEA (5.4) than in calves of CAS-CON (2.8) and BUL-CON (2.9) groups (P<0.05). From days 1 to 3 vocalizations decreased in all groups. CAS-CON and BUL-CON animals spent 20% lying on day 1 after weaning compared with 40% in CAS-WEA and BUL-WEA calves (P<0.05). The haptoglobin concentration decreased during the first 5 weeks after weaning in all groups independent of the castration, weaning group or its interaction (P>0.05). WEA groups showed an increased average daily gain (ADG) during weeks 0 to 3 and a reduced ADG during 4 to 7 weeks in comparison with CON animals. At slaughter, bulls were about 80 kg heavier than castrates and had a superior dressing percentage and carcass classification (P>0.05). In conclusion, weaning had a greater effect on the number of vocalizations, standing/walking and lying behaviour and ADG compared with Burdizzo castration. In comparison with undertaking the procedures separately, concurrent castration and weaning neither affected behaviour and haematological parameters nor impaired performance. There was no evidence that the concurrent application of both treatments markedly increased the stress response compared with their application at intervals of a few weeks.

An experiment was carried out in growing chickens to study the effect of supplementation of a semi-synthetic diet containing soya-bean meal as the sole protein source with DL-methionine, to improve its biological value, on the excretion of endogenous protein and amino acids measured in lower ileum and total tract using traditional methods. Thirty-two White Rock male broilers (10 days old) were randomly divided into eight groups each of four birds, of similar body weight (mean live weight: 142·8 (s.e. 0·68) g), and individually housed in metabolism cages. Following a paired-feeding design based on metabolic body weight (kgM0·75), each group of birds was given, for an experimental period of 20 days, each of four levels of protein (60, 120, 180 or 240 g/kg; 5 days each) in two groups of isoenergetic (14·5 kJ metabolizable energy per g dry matter) and semi-synthetic diets based on soya-bean meal, either not supplemented or supplemented with 2 g/kg DL-methionine (diets S and SM, respectively). After 3 days of each treatment excreta were collected for 48 h, frozen and stored at –20ºC. At the end of the fourth treatment three chickens of each group were killed and their lower ileal contents collected. The remaining chick of each treatment was fasted for 24 h and given a protein-free diet for 8 days and excreta were collected for the last 4 days. Then (day 39 of age), chickens were killed and lower ileum contents removed and stored at –20ºC. Samples of excreta and lower ileum contents were subjected to nitrogen (N) analysis by Kjeldahl procedure and amino acid (AA) analysis by high-performance liquid chromatography. Supplementation with DL-methionine of the soya-bean meal-based diets halved total tract endogenous AA losses. Regression analysis produced a higher estimation of ileal and faecal endogenous AA excretion than feeding a protein-free diet. Endogenous AA excretion determined in the lower ileum was higher than in excreta no matter which estimation procedure was utilized. In conclusion, supplementation of dietary protein with the first limiting AA to improve its protein quality, causes an important drop in endogenous AA losses, that may have an important effect on the N economy and energy requirements in poultry. The use of regression analysis on excreta data where graded amounts of protein are given to growing chickens, seems a suitable method for determining endogenous AA losses provided that good quality proteins are used.

Nucleus breeding schemes for dairy cattle give opportunities for selection on characteristics other than milk production, such as food intake or efficiency, and for the application of reproductive technologies such as embryo transfer. The emphasis in such schemes involving embryo transfer will be on early lactation measurements of production and food intake, to minimize generation intervals. The aim of this study was to examine the value of early lactation measurements of food intake and other characteristics in predicting longer-term food intake. Intakes of a complete diet, offered ad libitum, were available for 101 heifers up to week 38 of lactation, from the Edinburgh School of Agriculture's Langhill herd. Partial correlations between weekly dry-matter (DM) or metabolizable energy (ME) intakes in early lactation and cumulated intakes to week 38 of lactation, after fitting year and month of calving as fixed effects, and proportion of Holstein blood as a covariate, ranged from 0·27 for week 1, to 0·70 for week 12. Cumulated ME intakes, up to week 38, were regressed on shorter measures of ME intake, together with fat plus protein yield in weeks 1 to 10 of lactation. Other independent variables, such as point estimates of, or changes in, live weight, condition score and backfat depth did not further increase the precision of prediction. The means and standard deviations for milk yield, DM intake and ME intake up to week 38 of lactation were 5877 (s.d. 1087) kg, 4070 (s.d. 400) kg and 51579 (s.d. 4614) MJ respectively. For a fixed duration of intake recording, measurements taken later in lactation gave the most precise prediction of 38-week ME intake (e.g. residual s.d.s from models including 4-week cumulated ME intakes in weeks 1 to 4, 3 to 6 and 5 to 8 of lactation were 2865, 2636 and 2501 MJ respectively, with R2 values of 0·62, 0·67 and 0·71). Shorter periods of intake recording started in week 5 of lactation gave slightly more precise prediction than longer periods of recording started in weeks 1 to 4 (e.g. residual s.d.s from models including cumulative ME intakes in weeks 1 to 10, 3 to 10 and 5 to 10 were 2391, 2298 and 2277 respectively, with R2 values of 0·69, 0·75 and 0·76). These results have implications for the cost: benefit of food intake recording in breeding schemes.

Polymerase chain reaction (PCR) primers specific to exon 2 of the bovine lymphocyte antigen (BoLA)-DRB3 gene were used successfully to amplify the equivalent region in 34 Murrah and 36 Surti buffaloes selected at random. The 304 bp amplified product of the DRB3 gene was separately digested with BstγI, HaeIII and Rsal enzymes. Digestion with BstγI enzyme did not reveal any polymorphism and all animals showed a single restriction pattern, which corresponded exactly to the BstγI pattern ‘b’ previously described for cattle. Digestion with HaeIII enzyme resulted in five patterns, four of which corresponded to the Haelll patterns previously reported in cattle. The new HaeIII pattern was observed in both the breeds of buffaloes studied. The fragment analysis with RsaI revealed 13 different patterns. All of these RsaI patterns corresponded to the RsaI patterns previously described for cattle. The high degree of similarity in the restriction fragment length polymorphism (RFLP) patterns of cattle and buffalo observed in the present study provide evidence for the strong conservation amongst other bovine species, of restriction sites previously reported in cattle.

The performance of crossbred ewes sired by Border Leicester (BL), Bluefaced Leicester (BFL) and ABRO Damline (DL) crossing sires was compared. The dams of the crossbred ewes were of three hill breeds (Scottish Blackface, Swaledale and Welsh Mountain). Contemporary comparisons were made on 18 commercial and college farms throughout England and Wales from 1977 to 1981. A total of 1 277 crossbred ewes were involved with data on up to three years' lambings per ewe, giving a total of 3 522 mating records. The analyses were by least squares, fitting constants for terminal ram breed × farm × year of birth of ewe groups, sire breed, dam breed, age of crossbred ewe and all two-way interactions.

The DL crossbred ewes were lighter at mating than the other crossbreds at each age. The proportion of 1-year-old crossbred ewes lambing was highest for the DL (0·78), compared to BFL (0·73) and BL (0·62), indicating earlier sexual maturity. Over all ages, the DL crossbreds were more prolific with 1·79 lambs per ewe lambing compared to BFL (1·63) and BL (1·53) and more lambs were weaned (1·33, 1·29 and 1·19 respectively). The total litter weight at both birth and weaning of the DL crossbreds was greater than the BL crossbreds but less than the BFL crossbreds at each age. For prolificacy and early sexual maturity, the DL cross is superior to both breeds. In overall production, the DL cross had no advantage over the BFL cross, as the litters of the DL crossbred ewes were lighter than the BFL litters at both birth and 10 weeks of age

Phytoestrogens could be a useful tool in swine husbandry practices because of their structural and functional similarities to estradiol. The goal of this study was to compare various routes and doses of administration of the phytoestrogen genistein in sows of two different physiological statuses. Circulating concentrations of isoflavones, estradiol and IGF-I were determined. In experiment 1, 65 sows were equally divided into the five following groups, between days 3 and 5 of the first or second estrous cycle post weaning: (1) controls (CTL); (2) 1 g of genistein fed daily (OR1); (3) 2 g of genistein fed daily (OR2); (4) two daily i.m. injections of 200 mg of genistein (IM400); and (5) two daily i.m. injections of 400 mg of genistein (IM800). Treatments were carried out for 10 days. In experiment 2, 10 sows were equally divided into two groups on day 90 of gestation, namely, controls (CTL) or 2 g of genistein fed daily for 10 days (OR2). In both trials, jugular blood samples were collected on days 1 (before treatment), 5 and 10 at 0730 h. In experiment 1, a blood sample was also collected at 1730 h on day 10 for CTL, IM400 and IM800 sows. In experiment 1, circulating concentrations of genistein on days 5 and 10 were greater in OR2, IM400 and IM800 than in CTL and OR1 group sows (P < 0.01). Daily dietary supplementation with 2 g of genistein resulted in blood concentrations that were similar to those in animals given daily two i.m. injections of 200 mg. Values of all isoflavones, except equol, which was not detectable, were greater in PM than in AM on day 10 (P < 0.01). In experiment 2, genistein concentrations were greater in OR2 compared with CTL on days 5 and 10 (P ⩽ 0.05). There was no difference in the genistein response to OR2 because of physiological status (i.e. weaned v. gestating, P > 0.1). Estradiol and IGF-I concentrations were not altered by any of the treatments (P > 0.1). Providing genistein either per os or via i.m. injections increased circulating concentrations of genistein in female swine within 5 days of the onset of treatment. The genistein response to i.m. injections of genistein was similar in weaned and late-pregnant sows, even though endogenous concentrations of estradiol differed. This response was specific in that estradiol, IGF-I and isoflavones other than genistein were not affected by treatments.

In order to improve foal carcass quality, it is necessary in particular to improve the carcass dressing percentage and tissue composition. Thus, it is important to establish relationships between grading systems and these parameters. This research was conducted to study the effect of slaughter age (13 v. 26 months) and finishing feed (standard v. linseed feed) on carcass characteristics such as subcutaneous fat colour plus classification of foals for the degree of fatness and conformation. For this study, 46 foals of crossbred genotype (Galician Mountain×Burguete) were used. Finishing feed did not affect any parameter, whereas slaughter age influenced all parameters (P<0.05). The oldest foals had higher carcass measurements, 13% more of meat, 4% more of bone, 12% more of fat, and 4% and 9% bigger fore- and hindquarter, respectively. Consequently, bigger valuable prime cuts were obtained. Nevertheless, the meat : bone ratio was very similar for both 13- and 26-month-old foals (2.88). Most of 26-month-old foals were classified in ‘E’ (Extra) and ‘5’ (Complete fat cover) categories of conformation and degree of fatness. Most of the carcasses showed subcutaneous fat described as yellowish-white irrespective of age or diet. A regression model found that conformation (36%) and degree of fatness (33%) in live animals was positively linked with carcass tissue composition. It is therefore suggested that producers aim for older slaughter ages than 13 months and that the foal meat industry establishes grading systems to predict carcass quality. Further studies should be necessary to find the optimal slaughter age to obtain carcasses in the best categories of degree of fatness and conformation. New studies should be recommended to improve the meat : bone ratio of foal carcasses as it estimates the aptitude for meat production.

Plant secondary metabolites (PSM) are one of the promising options to control gastrointestinal nematodes in sheep and goats. The objective of this study was to assess the abilities of sheep and goats to self-medicate with tannin-rich sainfoin (Onobrychis viciifolia) (SF) when infected with gastrointestinal nematodes, using a cafeteria and an operant conditioning trial. Hypotheses were that parasitized (P) lambs and goat kids would show greater intake and preference for SF than their non-parasitized (NP) counterparts, that kids would eat more SF than lambs (due to their lower resistance against parasites and their greater ability to consume PSM), and that SF intake would increase over time for P animals. We used 20 female kids and 20 ewe lambs aged 3 months. Half of the animals per species (n = 10) were experimentally infected with 170 L3 larvae of Haemonchus contortus/kg of BW (P). The other half were free from parasites throughout the study (NP). Five weeks after infection, animals were exposed to a 24-day cafeteria trial (three 8-day periods) offering a free choice between two legume pellets: SF (3.8% condensed tannins) and alfalfa (ALF, Medicago sativa; no tannin). Subsequently, animals were involved in an operant conditioning trial of two 4-day long sessions, to assess in short-term tests their motivation to walk for a SF reward when offered in choice with freely available ALF. In the cafeteria trial, SF preference was greater in kids than in lambs, particularly in the first two periods. We did not observe a greater preference for SF in P animals, which was even greater in NP animals for periods 1 and 2. Sainfoin intake increased through periods for P animals, which led to similar SF preferences for all groups during period 3. In the operant-conditioning trial, motivation to get the SF reward was similar between P and NP animals. These results support the hypotheses that goats are more willing to consume tanniferous feeds than sheep, and that P animals increased SF intake through time. However, the emergence of a curative self-medicative behaviour was not supported, as P individuals did not show greater SF intake, preference, nor a greater motivation to get SF than NP animals, regardless of animal species. These findings are discussed with previous results and some explanations are presented.

One performance and one ileal apparent digestibility (IAD) trial were conducted to investigate the performance, nutrient digestibility and intestinal disaccharidase activity of weaner/grower pigs given diets containing Chinese stored brown rice (CSBR) extruded and with exogenous enzyme supplements. In experiment 1, 96 crossbred (Duroc X Landrace X Large White) piglets weaned at 24 days of age were randomly divided into four groups according to a 2 X 2 factorial design. The animals were given four diets: (1) CSBR without enzyme supplementation, (2) CSBR supplemented with 625 mg a-amylase (2509 enzyme activity units) and 200 mg glucoamylase per kg (20018 enzyme activity units) per kg diet, (3) a normal temperature extruded CSBR (NTECSBR) without enzyme supplementation, and (4) NTECSBR supplemented with 625 mg a-amylase (2508 enzyme activity units) and 200 mg glucoamylase (20010 enzyme activity units) per kg diet. Growth, food consumption and specific activity of disaccharides in sections of the digestive tract were measured. In experiment 2, six male grower pigs with a mean initial body weight 21 kg, fitted with a simple ‘T’ cannula at the terminal ileum were used in a 6X6 Latin-square design. In addition to CSBR and NTECSBR diets with and without enzymes, a low temperature extruded diet LTECSBR with and without enzymes (as for other diets) was introduced. IAD of nutrients was measured. Extrusion resulted in a poorer (P < 0.05) food/gain for weaned pigs. Extrusion and enzyme supplementation had no influence (P > 0.05) on average daily food intake and average daily gain. Extrusion tended to improve (P = 0.075) IAD of starch but IAD of energy, dry matter, crude protein and amino acids were not influenced (P > 0.05). Enzyme supplementation had no effect on IAD of amino acids (P > 0.05), except for increasing IAD of lysine, threonine and isoleucine (P < 0.05). Extrusion and enzyme supplementation resulted in a higher (P < 0.05) maltase activity in the duodenum at day 14 of the trial. However, extrusion decreased (P < 0.05) the activity of maltase, isomaltase, sucrase and lactase in the jejunum at day 28. Enzyme supplementation increased (P < 0.05) the activities of maltase, isomaltase, trehalase and lactase in the jejunum at day 28. There was a positive extrusion X enzyme interaction (P < 0.05) for the activity of maltase and trehalase in the duodenum at day 14; a negative interaction was observed for the activity of lactase, maltase, isomaltase and trehalase in the jejunum at day 28. The results suggest that neither extrusion nor enzyme supplementation are necessary for CSBR to be used in pig diets.

The aim of this study was to determine the developmental ability of cloned embryos derived from porcine neural stem (NS) cells, amniotic fluid-derived stem (AFS) cells, differentiated cells from NS and AFS cells, fetal fibroblast (FF) cells, adult fibroblast (AF) cells and mammary gland epithelial (MGE) cells. NS, AFS and FF cells were isolated from embryonic day 30 porcine fetus, AF and MGE cells were isolated from adult pig. NS and AFS cells were induced to differentiate into different cell types, respectively. Stem cells and their differentiated cells were harvested for analysis of the markers using reverse transcription PCR. NS and AFS cells, their differentiated cells, FF, AF and MGE cells were used for nuclear transfer, respectively. A total of 100 two-cell stage cloned embryos derived from each cell line were transferred into the oviducts of surrogate mothers. The results showed that the neurospheres were positive for the undifferentiated neural cell marker, Nestin and NS cells widely expressed NogoA, DCX, CyclinD2, CD133, Hes1, Oct4, Desmin, CD-90, Nanog and Sox2. AFS cells widely expressed NogoA, DCX, CyclinD2, CD133, Hes1, Nanog, Sox2, Oct4, Desmin and CD-90. Both NS and AFS cells were differentiated into astrocyte (GFAP+), oligodendrocyte (GalC+), neuron (NF+, NSE+ and MAP2+), adipocyte (LPL+ and PPARγ-D+), osteoblast (Osteonectin+ and Osteocalcin+), myocyte (myf-6+and myoD+) and endothelium (CD31+, CD34+, CD144+ and eNOS+). Four cloned fetuses (28 and 32 days) derived from NS and AFS cells were obtained. The developmental potential of the cloned embryos derived from stem cells (NS and AFS cells) were higher (P < 0.05) than that of the cloned embryos derived from somatic cells (the differentiated cells from NS and AFS cells, FF cells, AF cells and MGE cells), which suggests that the undifferentiated state of the donor cells increases cloning efficiency.

The use of cottonseed (CS) as an energy and protein supplement to high wheat-straw diets was studied in a digestion and nitrogen balance trial, and as a component in fattening diets in a feeding trial. The proportions of CS studied were 0, 60, 120, 180 and 240 g/kg diet dry matter (DM). DM intake per kg M0·75 was 33, 31, 40, 31 and 29 g, respectively. The digestibility coefficient of organic matter was 415, 463, 417, 441, 350 g/kg DM and of neutral-detergent fibre was 350, 436, 411, 309, 334 g/kg DM. Nitrogen balance was –2·52, 1·1, 5·38, 5·63, 7·60 g/day respectively, for the same order of treatments. The effect of high proportions of CS in the diet in restricting DM intake and reducing its digestibility was evident. The results of the feeding trial were in agreement with those of the digestion trial and indicate the proportion of 120 g CS per kg DM as optimal and maximal.

The material for the present investigation included approximately 4000 cows in 50 progeny groups from the dual-purpose breeds Red Danish cattle and Black Pied Danish cattle. The main objective was to investigate production in 305 days of second lactation. The characteristics studied were milk yield, butterfat yield and fat content. Analyses of the influence of the four environmental factors, herd average, age at calving, calving interval and calving season, were carried out using least squares. It was shown that age at calving, calving interval and calving season had a curvilinear effect on the yield traits. Herd average yield had a strong linear effect on the yield traits. The reduction in the phenotypic variance due to regression of yield on environmental factors was about 35% for milk and butterfat, and about 18% for fat content.

Heritabilities for yield traits in second lactation as well as phenotypic and genetic correlations between the yield traits in first and second lactation were presented. The coefficients of repeatability for milk and butterfat yield diminished from 0·5 to 0·3 when the data were corrected for the environmental factors.

Ingestion of small amounts of some types of condensed tannins (CTs) by ruminant livestock can provide nutritional, environmental and economic benefits. However, practical methods are needed to make these tannins more available to ruminant livestock. Results from previous trials with crude quebracho and black wattle tannin indicated that cattle and/or sheep would not preferentially drink water containing these tannins. Therefore, we conducted preference trials to determine if cattle and sheep would learn to prefer water containing purified grape seed tannin (GST) that provided up to 2% of their daily dry matter (DM) intake. After gradual exposure to increasing amounts of this tannin in water during a pre-trial period, five adult ewes and five yearling heifers fed lucerne (Medicago sativa) pellets (19% CP) were offered water and several concentrations of GST solutions for either 15 (sheep trial) or 20 days (cattle trial). We measured intake of all liquids daily. Concentrations of blood urea were also measured for heifers when they drank only tannin solutions or water. Both sheep and cattle developed preferences for water with GST in it over water alone (P < 0.01) although this preference appeared earlier in the trial for sheep than for cattle. For the sheep, mean daily intake of water alone and all tannin solutions (in total) was 0.6 and 6.1 l, respectively. For the cattle, mean daily intake of water and all tannin solutions in total was 21.8 and 20.6 l, respectively, in the first half of the trial and 10.8 and 26.1 l, respectively, in the second half of the trial. Compared with the other tannin solutions, both sheep and cattle drank more of the solution with the highest tannin concentration (2% of daily DM intake as GST) than of water on more trial days (P < 0.05). Ingestion of water with the highest concentration of GST reduced blood plasma urea concentration in the cattle by 9% to 14% (P ⩽ 0.10) compared with ingestion of water alone. Results from the trials suggest that providing grape seed and perhaps other CTs via drinking water may be a practical way to introduce CTs into sheep and cattle diets.

The effect of monosodium L glutamate (MSG) on diet palatability and piglet performance during the suckling and weaning periods was studied in the course of five successive experiments involving a total of 230 litters during the suckling period and 120 pens of seven piglets during the post-weaning period. During the suckling period, the addition of 5 g MSG per kg diet led to a significant 0·36 proportional increase of creep food intake from the 18th day post farrowing. However, no increase in weaning weight was observed subsequent to the intake of the diet with added MSG. Moreover, in an experiment where MSG was added with an associated commercial flavour, no flavour enhancing effect of MSG was detectable. Few health problems were encountered at weaning and the number of scouring piglets was not related to one particular diet. During the first 13 days after weaning the addition of MSG to the diet increased daily food intake by proportionately 0·1 (P < 0·01) as well as growth rate by proportionately 0·07 (P < 0·01). Moreover, the addition of MSG to the diet was more effective with piglets of low weaning weight and thus contradicted the classical relationship between post-weaning performance and weaning weight. Finally, in an experiment where weaning occurred at lower ambient temperature, no improvement of post-weaning performance was observed following the addition of MSG.

The principles of domestic herbivore nutrition are well understood and have been developed through detailed physiological studies, although methods to accurately measure field-based intake still challenge herbivore nutrition research. Nutritional ecology considers an animal's interaction with the environment based on its nutritional demands. Although there are a number of theoretical frameworks that can be used to explore nutritional ecology, optimal foraging provides a suitable starting point. Optimal foraging models have progressed from deterministic techniques to spatially explicit agent-based simulation methods. The development of optimal foraging modelling points towards opportunities for field-based research to explore behavioural preferences within studies that have an array of nutritional choices that vary both spatially and temporally. A number of techniques including weighing animals, weighing herbage, using markers (both natural and artificial) and sampling forage, using oesophageal-fistulated animals, have been used to determine intake in the field. These intake measurement techniques are generally most suited to studies that occur over a few days and with relatively small (often less than 10) groups of animals. Over the last 10 years, there have been a number of advances in automated behavioural monitoring technology (e.g. global positioning systems) to track animal movement. A number of recent studies have integrated detailed spatial assessments of vegetation using on-ground sampling and satellite remote sensing; these data have been linked to behavioural preferences of herbivores. Although the recent studies still do not address nutritional interactions over months or years, they do point to methods that could be used to address landscape scale nutritional interactions. Emerging telemetry techniques used to monitor herbivore behavioural preferences and also to determine detailed landscape vegetation mapping provide the opportunity for future herbivore nutritional ecology studies.

Growth-promoters are banned by the European Community, but different hormonal cocktails are still illegally used. This experiment was therefore conducted to evaluate the effects of one of the most currently used cocktails on some hormonal parameters and spermatogenesis in finishing bulls in an attempt to provide a suitable screening technique for their illegal use. Sixteen double-muscled Belgian White Blue finishing bulls (mean ivcight: 535 (s.d. 37) kg) were blocked into control (C; no. = 7) and treated (Dex; no. = 9) groups. Animals were treated i.m. with the hormonal preparation (dexamethasone isonicotinate and phosphate, chlormadinone acetate and ethinyl oestradiol) on day 0, day 15 and day 30. Animals were slaughtered on day 45. Three h before each treatment and just prior to slaughter, jugular blood samples were collected to monitor the testosterone (T) response to an i.v. injection of gonadotropin releasing hormone (GnRH) (0·5 fig GnRH per kg body weight). Testicular tissue was also collected at slaughter. Plasma T and insulin-like growth factor-1 (IGF-1) concentrations were measured by radioimmunoassay. IGF-binding proteins (IGFBPs) were evaluated using Western ligand blotting. Daily weight gains were lower in the control group (1·29 (s.d. 0·13) kg for C v. 1·60 (s.d. 0·39) kg for Dex) but the difference ivas not significant. After treatment, spermatogonia, spermatocytes, spermatids and spermatozoa disappeared from the testis and seminiferous tubules consisted only of Sertoli cells; these observations suggest that treated animals were sterile. Moreover, plasma T concentrations in response to GnRH stimulation were suppressed fP < 0·001) in the Dex group between day 15 and day 45 (mean maximal responses: 5·4 to 7·9 μg/l in C group v. < 0·2 μg/l in Dex group at day 15, 30 and 45). Treatment did not show any prominent effect on plasma IGF-1 levels but increased IGFBPS band intensity. In conclusion, treatment with a cocktail containing dexamethasone esters, chlormadinone acetate and ethinyl oestradiol for a short period induced a number of changes in finishing bulls luhich might be possible to develop as a screening method for the identification of illegally treated animals.

The valorization of spent hens via the food chain has some major limitations, which include low meat yield and tough meat. The latter issue can be overcome by producing convenience foods; the first may be alleviated by employing a genotype with higher meatiness. To quantitatively compare two common layer genotypes in production performance, meat yield and sausage quality, 2200 57 weeks old Institut de Sélection Animale (ISA) Warren and Dekalb White hens each were investigated during the last 60 days of egg laying. The hens were housed in an aviary system in 2×10 compartments (10 compartments/each genotype). Measurements included feed intake, laying performance, egg weight and feed conversion ratio as measured per compartment. BW was determined twice on 10 animals per compartment. Finally, two sub-groups of five hens per compartment were slaughtered, meat yield was recorded and bratwurst-type sausages were produced (n=20 per genotype). Fat proportion, cooking loss, connective tissue properties and Kramer shear energy were measured. After 1, 4, 7 and 10 months of frozen storage, oxidative stability (thiobarbituric acid reactive substances (TBARS)) and microbiological status were determined as shelf-life related criteria. ANOVA was performed considering genotype as the main effect. The ISA Warren hens were inferior in laying performance (−11%) and feed conversion ratio (+10%) compared with Dekalb White, but had the same feed intake. The ISA Warren had higher BW and carcass weight than the Dekalb White. Carcass yield was higher by 5.9%. There were 80 g (23%) more meat available for sausage production from ISA Warren compared with Dekalb White. Sausages prepared from meat of ISA Warren hens contained less fat than those from Dekalb White, but showed the same cooking loss. Although the collagen proportion of the sausages produced from ISA Warren was lower than from Dekalb White, collagen solubility was lower and shear energy was higher. During the 10 months of frozen storage, TBARS increased continuously, but not to an extent that would prevent its use as food. The sausages from the ISA Warren genotype had marginally higher TBARS levels during storage. Total colony counts decreased with storage time, with slightly lower values found in the non-spiced sausage material from the ISA Warren hens. In conclusion, when intending to use spent hens as food, ISA Warren are clearly superior to Dekalb White in meat and sausage yield. When processing the meat to sausages, the higher shear energy is probably advantageous.

The feeding patterns of sows using electronic feeders were monitored automatically (via a computer interface) over a period of 15 months. This paper reports on the variability in the size of the first meal of the day in relation to total daily food intake. The results demonstrated a pattern that bears some similarity to that observed by other workers, namely that sows tend to take all their daily food allocation in a single meal. In general, sows (79%) ate most of their daily allowance in a single visit to the feeders. However, on a significant minority of occasions (21%) this was not the case. The results also showed that there was a considerable number of sows (87% of the herd) that fed in a variable pattern, i.e. considerable variation in the proportion of their daily allowance taken in a single visit. This unpredictability was found throughout the sow herd. Some, but not all of this variability could be attributed to differences between parities (P < 0·001) and also there was some evidence that some sows, when newly introduced into the herd, were more variable in behaviour than more established sows. However, a large amount of variation remains unexplained. The need to provide flexible sow management to accommodate individual behaviour is discussed. Additionally, appropriate sampling periods of considerable duration are shown to be important in describing feeding patterns of group-housed sows.

Twenty-four cows were used in a randomized block, continuous feeding trial to examine the effects of including 0, 25 or 50% of dried grass in a concentrate given to cows receiving grass silage ad libitum. The concentrates also contained barley, and soya bean meal to maintain the crude protein content at 16%, and were given at the rate of 0·4 kg/kg of milk. The treatments were imposed for a 6-week period after a preliminary feeding period of 4 weeks. At the beginning of the experiment the cows had, on average, calved 39 days previously. The mean intakes of silage dry matter were 7·60, 8·28 and 8·39 kg/day with the concentrates containing 0, 25 and 50% dried grass, respectively, and were significantly greater when dried grass was included in the concentrate. The mean milk yields of 200, 18·2 and 19·6 kg/day for the three treatments respectively were not significantly different. Body-weight change and milk composition were not significantly different between treatments.