Golden hamsters of one common laboratory strain had a high incidence of hydrocephalus internus. When a severity score of hydrocephalus was used, a major autosomal recessive locus could be identified. However, when a binary score (hydrocephalus, no hydrocephalus) was used, no such major locus could be detected and results of test matings were not consistent with Mendelian inheritance. Golden hamsters with severe forms of hydrocephalus had a dorsally compressed and ventrally intact hippocampus. Implications for the behavior and well-being of affected hamsters are unknown but researchers using this strain should be aware of the likely presence of hydrocephalus.

In spite of the improvement in management and the breeding goal of increasing the number of piglets born alive, piglet mortality is still a substantial problem in pig breeding. The objective of the first part of the study was to estimate genetic parameters for different causes of piglet losses and to investigate the relationship to litter-size traits. Data were collected on a nucleus herd from January till December 2004. Records from 943 German Landrace sows with 1538 pure-bred litters and 13 971 individually weighted piglets were included. Four different causes of piglet losses (LOSS) were evaluated. Additional analysed traits were underweight and runting. Furthermore, the fertility traits number of piglets born alive, born in total and stillborn piglets as well as the individual birth and weaning weights were analysed. The different LOSS were treated as a binary trait and subsequently the heritabilities were estimated using a threshold model. The most important LOSS was crushing under the sow (12.4%). The survival rate and crushing had a heritability of h2 = 0.03. The fertility traits piglets born alive, born in total and stillborn piglets were analysed with a linear model and heritabilities rank from h2 = 0.05 (stillborn) to h2 = 0.10 (born alive). The estimated heritabilities for birth- and weaning weight were both h2 = 0.10. The genetic correlations between number of piglets born alive and each LOSS trait were analysed bivariately. Of all piglets born alive 84.3% survive the lactation period. Survival decreased with increasing litter size (rg = −0.54 up to −0.78) and the probability of being crushed under the sow increased.

The aim of the study was to analyse the genetic background of different traits to characterise the maternal behaviour of sows and to evaluate the relationship to different causes of piglet losses – increasing piglet survival due to higher maternal abilities of the sow. A total of 1538 purebred litters from 943 German Landrace sows in the year 2004 were available for data analysis. Around 13 971 individually earmarked piglets were included in the analyses. Maternal abilities were characterised through the sow’s reaction to the separation from her litter during the first 24 h after farrowing, and on day 21 of lactation, the reaction towards the playback of a piglet’s distress call and the reaction towards an unknown noise (music). In 1220 of these litters, the sows were also scored for aggressiveness in the group when regrouped before entering the farrowing crates. To describe fertility, the number of piglets born alive, stillborn piglets, number of piglets born in total and the individual birth weight were utilised. Different causes of piglet losses were evaluated as binary traits of the dam with survival rate, different definitions for crushing by the sow, being underweight and runts. The heritability for being aggressive in the group was h2 = 0.32 and for the behaviour traits during lactation, the heritabilities ranged from h2 = 0.06 to 0.14. The genetic correlations showed that more-reactive sows had fewer piglet losses.

Footrot is a costly endemic disease of sheep. This study investigates the potential to decrease its prevalence through selective breeding for decreased lesion score. Pedigreed mule and Scottish Blackface (SBF) ewes were scored for lesions on each hoof on a 0 to 4 scale for up to 2 (SBF ewes) or 4 (mules) times over 2 years. One score was obtained for SBF lambs. An animal was deemed to have lesions (severe lesions) if at least one hoof had a score of at least 1 (2). The prevalence of lesions was 34% in lambs, 17% in SBF ewes and 51% in mules. The heritability of lesions (severe lesions) analysed as repeated measurements of the same trait in a threshold model was 0.19 (0.26) in SBF ewes and 0.12 (0.19) in mules. Estimates for the sum and maximum of scores as well as the number of feet affected were much lower, as were estimates for permanent animal effects (i.e. non-genetic effects associated with an animal). When successive scores on the same animal were analysed as correlated traits, heritability estimates for most traits tended to be higher, except for severe footrot in mules where estimates varied greatly over time. The phenotypic correlations between successive scores in SBF ewes were close to 0, genetic correlations were moderately positive (0.18 to 0.55). Correlations in mules were generally of a similar size, but some genetic correlations were higher (up to 0.92). There was a clear trend for heritabilities for lesions and severe lesions to increase with higher prevalence of lesions, even when analysed in a threshold model. Heritability estimates for traits that combine scores over several events in mules, identifying the more persistently affected animals, ranged from 0.12 to 0.23 with the highest estimates for the average number of feet that were (severely) affected in animals scored for a minimum at two events. The heritability of all lesion traits in lambs was estimated as 0. It is concluded that selection for lower lesions is possible in ewes but not lambs, and that a simple binary score at an animal level is at least as effective as a comprehensive score at hoof level. Given the low repeatability of lesion scores, repeated measures over time will improve effectiveness of selection. Selection across environments (flocks, seasons) with different prevalences of lesions scores will need to take account of variation in the heritability.

The study examined the growth performance of pigs offered liquid feed or dry feed on either a restricted or an ad libitum basis, and whether their growth performance was further influenced by the water-to-feed ratio. The study was split into two parts to enable unrestricted (trial 1; n = 64) and restricted (trial 2; n = 48) feeding to be compared. Male pigs were randomly allocated to six dietary treatment groups. A standard dry pellets diet (D) was offered either as: (i) unrestricted ration (UR); (ii) restricted ration (R); or D soaked in water at a feed-to-water ratio of (iii) 1 : 1.5 restricted (1 : 1.5 R); (iv) 1 : 3 unrestricted (1 : 3 UR); (v) 1 : 3 restricted (1 : 3 R); or (vi) 1 : 3 restricted with the addition of lactic acid to adjust the feed to pH 4 (1 : 3(4) R). Liquid feeding improved (P < 0.05) average daily live-weight gain (ADG) and lean tissue growth rate (LTGR) in the 1 : 3 UR compared with DUR but did not alter feed conversion ratio (FCR). Within the R groups, ADG were greater in all of the 1 : 3 diets, whereas feed intake, and hence FCR, was lower (P < 0.001) in these groups when offered the R ration. In conclusion, liquid feeding has a beneficial influence on the performance of modern porcine genotypes during the growth/finishing phase and this is further modulated by the water-to-feed ratio.

Seventy-eight Cotswold piglets weaned from sows receiving 0% or 2% conjugated linoleic acid (CLA)-supplemented rations from day 85 of gestation through lactation were allocated to nursery diets (ND) according to their dam’s lactation ration (LR) as follows (1) 0%-0% (0% CLA LR: 0% CLA ND, n = 17); (2) 0%-2% (0% CLA LR: 2% CLA ND, n = 17); (3) 2%-0% (2% CLA LR: 0% CLA ND, n = 23); and (4) 2%-2% (2% CLA LR: 2% CLA ND, n = 21). At 28 ± 2 days of age all piglets received an oral Escherichia coli K88+ (enterotoxigenic Escherichia coli, ETEC) challenge and were subsequently monitored for scour development and overall health until 36 ± 2 days of age, after which blood and tissue samples were collected. Piglet BW was not affected by dietary CLA supplementation to LR (P > 0.05). However, by day 36 piglets receiving 2% CLA-supplemented ND were significantly lighter (P < 0.05) than piglets receiving control diets. Average daily gain and feed efficiency were not affected by CLA supplementation. Average daily feed intake (ADFI) was greater for piglets weaned from 2% CLA-supplemented sows from day 17 to 28 (P < 0.05), otherwise ADFI was unaffected by dietary CLA supplementation (P > 0.05). The development of scours was less severe in piglets weaned from 2% CLA-supplemented sows at 8, 24, 48 and 56 h after ETEC challenge (P < 0.05). Intestinal coliform and lactic acid bacteria populations post challenge were not affected by CLA supplementation. However, cecal ammonia-N was numerically greatest in 0%-0% piglets compared to the other treatment groups, and the total volatile fatty acid production was numerically lower in 0%-0% and 0%-2% piglets compared to 2%-0% and 2%-2% piglets. In addition, piglets weaned from 2% CLA-supplemented sows had increased serum immunoglobulin A (P < 0.001) and G (P < 0.05) levels and reduced (P < 0.05) intestinal mucosal inflammation compared to piglets weaned from control sows. Although there were no obvious additional health effects observed when CLA was provided in ND, supplementing sow rations with 2% CLA from mid-gestation through weaning appears to have immune-stimulating carry-over effects post weaning. Thus, supplementing sow rations with CLA may be a practical strategy for enhancing passive immune transfer and improving the immune status and overall gut health of nursery piglets.

Two trials were performed to assess changes in the physicochemical properties of precisely processed (micronised v. extruded) wheats, prior to inclusion in piglet diets. The in vitro data obtained were subsequently related to biological responses of newly weaned piglets over 14 days. The effects of the severity of micronisation (Trial 1) or extrusion (Trial 2) on the nutritional value of two wheats (varying in endosperm texture) were examined. Extrusion, in contrast to micronisation, drastically disrupted the structural properties of wheat starch granules through melting of crystallites and macromolecular degradation of starch polysaccharides. These structural changes strongly improved the hydration characteristics of starch and its digestibility. The amount of starch digested in vitro was approximately 0.20, 0.70 and 0.90 for the unprocessed, micronised and extruded samples, respectively. This enhanced in vitro digestibility correlated well with, and helped to explain, the significant improvement in the apparent digestibility of starch at both the 0.5 region (mean coefficients for extruded wheat were 0.869 and 0.959 v. raw 0.392; P = 0.017) and 0.75 region (extruded 0.973 v. raw 0.809; P = 0.009) of the small intestine, when compared with piglets fed an unprocessed wheat diet. Extrusion and, to a lesser extent, micronisation lessened the reduction in apparent starch digestibility on day 4 post-weaning, typically seen at the 0.5 intestinal region in piglets fed an unprocessed wheat diet. Processing variables influenced both in vitro and in vivo data, with for instance, a positive relationship between specific mechanical energy (SME) input during extrusion and starch digestibility at the 0.5 region. The higher digestibility coefficient observed at the 0.5 region for the high SME diet suggests enhanced digestion and more rapid release of starch. However, it remains to be seen whether a diet containing rapidly digestible, as opposed to slowly digestible, starch is more beneficial for piglets. This rate of starch breakdown in the piglet is an important finding, which may have implications in helping to alleviate the post-weaning growth check, particularly in the absence of in-feed antibiotic growth promoters. Processing did not appear to offer any benefit over unprocessed wheat with regard to daily live-weight gain or the apparent digestibility of nitrogen in the small intestine over the 14-day period. Based on the enhanced in vivo starch digestibility, performance might be improved over a longer period, although future studies are required to confirm this. Precise processing variables for raw materials must be stated in all animal trials.

This experiment was designed to investigate the effects of meal-time feeding and protein restriction on performance, gait score (GS) and carcass and bone traits in broilers. A total of 420 1-day-old chicks were wing banded and randomly distributed into 21 pens with 20 chicks each. At 7 days of age, chicks were weighed and randomly assigned to one of the three treatments: (1) control (C) feed (23.02% crude protein (CP)) was available ad libitum; (2) meal-time feeding (MF); control feed was available from 0100 to 0900 h and from 1500 to 2300 h. Food was withdrawn from 0900 to 1500 h and whole wheat (10 g/bird per day) was dispersed on the floor from 7 to 21 days; and (3) low-protein (LP) diet (19.71% CP) was fed to the chicks from 7 to 21 days. All of the groups were fed ad libitum from 1 to 7 days of age and from 21 to 45 days of age with a standard commercial diet. Individual body weight was measured on days 7, 21 and 45. Feed consumption was measured from 7 to 21 days and from 21 to 45 days. Forty-two chicks were humanly slaughtered and eviscerated for bone evaluation, on days 21 and 45. Also carcass characteristics were determined on day 45. Control group body weight was significantly higher (P < 0.05) at 21 and 45 days of age than the MF and LP groups, which did not differ. Feed intake was reduced by meal-time feeding and LP diet (P < 0.01). Feed efficiency was the best in the MF group during the period of 21 to 45 days of age (P < 0.01). In the control group, shank was significantly longer than that of the LP group and tibia breaking strength was higher than that of the MF group at 21 days (P < 0.05). However, shank width, tibia wet weight and tibia mid-diaphysis ash percentage of the MF group were significantly lower than those of the C and LP groups at 21 days of age (P < 0.05). GS, shank and carcass and tibia bone traits on day 45 were not significant among groups. No compensatory growth and walking ability improvement were observed at 45 days of age for broilers fed with MF and LP between 7 and 21 days of age.

In vivo and in situ digestive characteristics of sainfoin (Onobrychis viciifoliaL., a tannin-rich forage) and lucerne (Medicago sativa L., a tannin-free forage) were compared to evaluate the effects of condensed tannins (CT) and growth stage (vegetative v. early flowering) in experiment 1. In experiment 2, the hays of the two forages, harvested at early flowering, were compared. Ingestibility, organic matter digestibility (OMD) and nitrogen (N) retention were measured in sheep fed sainfoin and lucerne fresh forages and hays. The loss of dry matter (DM) and N from polyester bags suspended in the rumen, abomasum and small intestine was also measured using rumen fistulated sheep and other intestine fistulated sheep. Nitrogen content was lower in sainfoin than in lucerne. Content of CT in sainfoin decreased with growth stage (3.5 to 2.5 g CT/kg DM) and was lower for sainfoin hay (0.6 g CT/kg DM). Ingestibility and OMD did not differ between fresh-fed forage species. Total N tract digestibility in vivo was much lower for sainfoin than for lucerne fresh forages (mean value 0.540 v. 0.721, P < 0.001) and for sainfoin hay than lucerne hay (0.464 v. 0.683, P < 0.001). In both species, N digestibility was not altered by growth stage. The rumen degradation of N was lower in sainfoin than in lucerne, resulting in a lower proportion of N intake excreted in urine. The intestinal digestibility of sainfoin was also lower than that of lucerne, resulting in a higher N excretion in faeces. Hence the efficiency of N utilisation by sheep (ENr) was similar (mean value 0.205 and 0.199 g N retained/g N intake for fresh sainfoin and lucerne, respectively). The coefficient of N retention by the animal was higher for sainfoin at the vegetative stage than for all the other forages. Nitrogen degradability in the rumen determined by the nylon bag technique (DegN) was lower for sainfoin than for lucerne when forages were studied both fresh (mean value 0.608 and 0.818, respectively) and as hays (0.631 and 0.767). The efficiency of forage N digestion (ENd) was higher for sainfoin at the vegetative stage. Compared with lucerne, sainfoin greatly increased the in situ estimate of forage N escaping the rumen but decreased its intestinal digestibility.

The objective of this study has been to develop a prediction equation of fat-free mass (FFM) from buffalo calves. Twenty buffaloes were fed ad libitum access at unifeed, with vitamin–mineral integration, for 14 months. Seven days before slaughtering, the animals were weighed and bioelectrical impedance measurements were collected. The data were analyzed by multiple linear regressions to evaluate the relationship between FFM and various predictor variables. Stepwise regression was used to eliminate variables that did not influence variation in the model. The value of resistance collected showed a decrease when the electrical frequency increases, while the values of reactance (Xc) increase. When using live weight (LW) and reactance at 500 and at 1000 kHz as independent variables, we obtained the best R2 Adj (0.967) and Durbin Watson statistic (2.596) that explain the prediction model (FFM = − 30.59 + 0.993LW + 0.150Xc500 − 0.123Xc1000 + 9.11). These results indicate that the use of bioelectrical impedance analysis has excellent potential as a rapid method, with minimal perturbation for the animal, to predict FFM in buffalo.

This study was done to evaluate the effects of two sublethal doses of gossypol (4 and 20 mg/kg of BW, every other day) on some amino and fatty acid concentrations in male rabbit seminal plasma. Rabbits were chosen as an experimental animal owing to the fact that they are excellent model for reproductive toxicological effects. The experiment lasted 16 weeks and included two periods: a treatment period (first 8 weeks) where the animals were given the tested product, and a recovery period (second 8 weeks) where all drugs were withdrawn. Results showed that total amino acids (TAA), total essential amino acids (EAA), total non-essential amino acids (non-EAA) and EAA/non-EAA ratio were decreased in a dose-dependent manner during gossypol treatment. The deleterious effect on TAA concentrations was mainly due to the reduction in total EAA. However, these concentrations regained their normal values after gossypol cessation. Basic, acidic, neutral amino acids and basic/acidic amino acids ratio decreased in a dose-dependent manner by gossypol treatment. Additionally, gossypol administration caused decreases in total unsaturated fatty acids (USFA) and increases in total saturated fatty acids (SFA) and the SFA/USFA ratio in a dose-dependent manner. During the recovery period, total SFA and USFA showed significant reduction and significant increase, respectively, after gossypol withdrawal. In conclusion, gossypol administration affected rabbit seminal plasma concentrations of amino and fatty acids in a dose-dependant manner. Gossypol reduced TAA, total EAA and total non-EAA. Additionally, gossypol caused decreases in total USFA and increases in total SFA. These deleterious effects were associated with poor-quality semen observed in our previous studies.

An option to increase the productivity of saline land is to graze sheep on salt-tolerant plants, which, during the summer/autumn period, can contain 20% to 25% of their dry matter as salt. This study assessed the impact of coping with high dietary salt loads on the reproductive performance of grazing ewes. From the time of artificial insemination until parturition, 2-year-old maiden Merino ewes were fed either a high-salt diet (NaCl 13% of dry matter) or control diet (NaCl 0.5% of dry matter). Pregnancy rates, lamb birth weights, milk composition and the plasma concentrations of hormones related to salt and water balance, and energy metabolism were measured. Leptin and insulin concentrations were lower (1.4 ± 0.09 v. 1.5 ± 0.12 ng/ml; (P < 0.05) and 7.2 ± 0.55 v. 8.2 ± 0.83 ng/ml; P < 0.02) in response to high-salt ingestion as was aldosterone concentration (27 ± 2.7 v. 49 ± 5.4 pg/ml; P < 0.05), presumably to achieve salt and water homeostasis. Arginine vasopressin concentration was not significantly affected by the diets, but plasma concentration of T3 differed during gestation (P < 0.02), resulting in lower concentrations in the high-salt group in the first third of gestation (1.2 ± 0.18 v. 1.3 ± 0.14 pmol/ml) and higher concentrations in the final third of gestation (0.8 ± 0.16 v. 0.6 ± 0.06 pmol/ml). T4 concentration was lower in ewes ingesting high salt for the first two-thirds of pregnancy (162 ± 8.6 v. 212 ± 13 ng/ml; P < 0.001). No substantial effects of high salt ingestion on pregnancy rates, lamb birth weights or milk composition were detected.

The post-fertilisation developmental capacity of bovine oocytes recovered by ultrasound guided transvaginal follicular aspiration (ovum pick-up, OPU) is influenced by diet-induced changes in hormone and metabolite concentrations. The objectives of this experiment were first to determine whether post-prandial changes in hormone concentrations, induced by changing the frequency of feeding, influenced oocyte quality and second whether changes in plasma glucagon concentration were associated with oocyte quality. Using a 2 × 2 factorial design, Holstein heifers (six per treatment) were fed either fibre- or starch-based diets containing either 189 or 478 g starch/kg dry matter. The diets were offered in either two or four equal meals per day and supplied twice the maintenance energy requirement. Blood samples were obtained both at weekly intervals (three samples per heifer, collected before feeding) during the experiment and throughout an entire 24-h period (15 or 17 samples per heifer for twice or four times daily-fed heifers, respectively). Each heifer underwent six sessions of OPU (twice weekly) beginning 25 days after introduction of the diets. Oocyte quality was assessed by development to the blastocyst stage in synthetic oviductal fluid following in vitro fertilisation. Mean weekly plasma insulin concentrations did not differ between diets, but plasma glucagon concentrations were greatest when heifers were fed the starch-based diet twice daily compared with the other diets. When heifers were offered four meals per day, there were no meal-related changes in hormone concentrations. However, when heifers were offered two meals per day, plasma insulin concentration increased after feeding the starch-based, but not the fibre-based diet. Plasma glucagon concentration increased after meals when heifers were fed twice daily and the increase was substantially greater when the starch-based diet was fed. Treatments did not influence (overall mean with mean ± s.e.) ovarian follicle size distribution or oocyte recovery by OPU (6.2 ± 0.4 per heifer), the proportion of oocytes that cleaved following insemination (0.57 ± 0.030) or blastocyst yield (0.27 ± 0.027 of oocytes cleaved). In conclusion, by feeding diets differing in carbohydrate source at different frequencies of feeding, meal-related changes in plasma hormone profiles were altered significantly, but oocyte quality was not affected. Therefore effects of diet on oocyte quality appear not to be mediated by meal-related fluctuations in hormone concentrations.

Objective: To evaluate mesometrial transplantation of frozen-thawed ovarian tissue in rabbit and to choose the optimized fertilization method for oocytes retrieved from grafts by investigating the capability of oocyte fertilization and further development. Forty rabbits were divided into three groups randomly: control group, fresh tissues transplantation group and frozen-thawed tissues transplantation group. Three months after the transplantation, rabbits were stimulated with FSH and oocytes were retrieved 13 h after human chorionic gonadotropin (HCG) injection. Oocytes matured in vivo or in vitro were then fertilized by conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), followed by observation and evaluation of fertilization rate and blastocyst formation rate. Blastocytes embryos were transferred to pseudopregnancy rabbits to observe pregnancy rate and birth rate. There were no significant differences in the percentage of oocytes matured either in vivo or in vitro among the three groups. The fertilization rate, cleavage rate and blastocyst formation rate of in vivo-matured oocytes had no difference among the three groups, whether they were fertilized by IVF or ICSI. Significantly higher fertilization rates of in vitro-matured oocytes were observed with ICSI compared with IVF in each group. The blastocyst formation rate of in vitro-matured oocytes was significantly lower than that of in vivo-matured oocytes in each group. The birth rate of in vivo-matured oocytes was significantly higher than that of in vitro-matured oocytes, although the pregnancy rate was similar between them. Mesometrial transplantation of frozen-thawed ovarian tissue may provide favorable conditions for follicle development. Oocytes retrieved from mesometrial grafts can develop to the blastocyst stage and produce live offspring. ICSI can optimize the fertilization rate of in vitro-matured oocytes retrieved from grafts.

The pacific white shrimp, Litopenaeus vannamei, is a popular species in aquaculture. Abdominal muscle accounts for 90% of shrimp flesh. Its growth and related genes, particularly the regulatory genes, is not well known. A cDNA library of shrimp juvenile abdominal muscle was established by PCR-based SMART™ cDNA technology. Library size was 5.0 × 106 pfu (plaque-forming unit) independent clones per microgram of starting RNA with the percentage of recombinant clones >95%. Sequence analysis of 311 randomly picked positive clones revealed 197 expressed sequence tags with average insert size of 745 nucleotides, 56% (110 of 197) clones having 5′-end sequence and 44% (87 of 197) clones having 3′-end sequence. Queries of the sequences by Blast identified 37 unknown sequences, and 160 unique clones, including 67 sequences of 100% identity matches, 28 high homologies (80% to 90% sequence match, >100 bits hit score in Blastn), 65 medium homologies (>100 bits hit score in Blastp) to the known EST sequences in the database. Among the high identity-matched ESTs, 12S ribosomal RNA, actin 1, actin 2, arginine kinase and beta-actin were the most abundant transcripts with 5 to 20 times of hit. Primary hit sequences originate from shrimp, insects, lobsters, crabs and crayfish. The EST sequences were categorized as muscle structural proteins (25%), rRNA and protein synthesis (25%), followed by mitochondrial functions (22%), exoskeleton (14%), enzymes (6%) and RNA splicing (2%), suggesting abundant and diverse transcripts present in the shrimp abdominal muscle cDNA library.

The time at pasture of dairy cows is often restricted in the context of extending the grazing season in autumn or at the end of winter. The objective of our study was to evaluate the effects of a restriction of time at pasture on milk production, herbage intake and feeding behaviour in dairy cows according to feeding regime. The four treatments consisted of 4 h or 8 h of time at pasture per day tested under two feeding regimes combining rate of supplementation and herbage allowance: either a high rate of supplementation (10 kg dry matter (DM) of a maize silage-soya bean meal mixture in the ratio 87 : 13 on a % DM basis) with a low herbage allowance (6 kg DM/cow per day above 5 cm), or a low rate of supplementation (5 kg DM of the same supplement) with a high herbage allowance (11 kg DM/cow per day). The study was carried out according to a 4 × 4 Latin square design with four 2-week periods, with 48 mid-lactation Holstein cows. The cows in the 4-h treatment had access to pasture from 0900 h to 1300 h and those in the 8-h treatment from 0900 h to 1700 h. The supplement was given at 1830 h. When time at pasture was reduced from 8 h to 4 h per day, herbage intake decreased (9.9 v. 8.1 kg DM, P < 0.001), along with a fall in milk production (22.3 v. 21.2 kg, P < 0.001) and milk protein concentration (30.1 v. 29.6 g/kg, P < 0.001), while milk fat concentration increased (39.4 v. 39.9 g/kg, P < 0.05). The effect of time at pasture on milk production was slightly more marked on the low-supplement feeding regime (interaction P < 0.06). Reducing time at pasture by 4 h led to a sharp decrease in grazing time (327 v. 209 min, P < 0.001), but strongly increased the pasture intake rate (31 v. 39 g DM/min, P < 0.001) and the proportion of time spent grazing (0.68 v. 0.87, P < 0.001). Cows showed a stronger motivation for grazing when receiving the low-supplement feeding regime. In conclusion, we showed that reducing time at pasture from 8 to 4 h for cows receiving 5 to 10 kg DM of a maize silage-based supplement decreased moderately milk production and herbage intake, because of the capacity for behavioural adaptation by the grazing dairy cows.

Much research has been carried out and published on dairy replacement management, in order to rear heifers as efficiently as possible, from both a technical and economical point of view. In most cases, the aim is to rear the heifers at the lowest cost possible without any deleterious effects on future performances. However, the importance of dairy heifer husbandry is not sufficiently well recognized and probably mishandled by most farmers. The present review aims to give an actual overview of rearing procedures in dairy heifers and possible ways to achieve optimal goals. For many years, it has been well known that rapid rearing lowers the age of sexual maturity and consequently may be an efficient way to reduce the non-producing period prior to conception. But this may impair mammary development and consequently future milk production, at least during first lactation. In addition, a growth rate that is too low may not only be costly but also result in animals that are too fat at first calving, creating problems such as calving difficulties, dystocia, etc. Genetic considerations must also be factored, i.e. frame, size, body weight, etc. have changed during the last 20 years and there are differences between breeds. As a result, some time-honoured recommendations may not be appropriate. The present paper reviews factors and management practices that may affect rearing and subsequent performance of dairy heifers.

The research was carried out to evaluate the effect of different α-tocopherol concentrations in lamb meat on oxidative stability during storage in high-oxygen atmosphere. Thirty-six lambs were randomly distributed to four groups and given diets containing four levels of vitamin E (20, 270, 520 and 1020 mg vitamin E/kg feed) from an initial weight of 13.2 ± 0.5 kg to a slaughter weight of 26.2 ± 0.3 kg. Supplementation of the diet with vitamin E increased (P < 0.001) the concentration of α-tocopherol in the meat and concentrations were obtained in the 0.46 to 4.14 mg/kg meat range. Broken-line analysis of data indicated a target dietary vitamin E supplementation of 287 mg/kg feed, which corresponded with a concentration of 2.26 mg α-tocopherol/kg meat. α-Tocopherol in meat was highly correlated with the oxidation of lipids and pigments. Broken-line analysis of data indicated the target α-tocopherol concentration in lamb for improved protection against lipid and pigment oxidation during 14, 21 and 28 days of storage in high-oxygen atmosphere was in the range 1.87 to 2.37 mg/kg meat. These concentrations of α-tocopherol in the meat made it possible to maintain the indicator values of lipid and pigment oxidation below the values considered in the bibliography as unacceptable to the consumer.