A comparison of the protective action of chicken and quail egg yolk in the cryopreservation of Spanish ibex epididymal spermatozoa

Egg yolk-based diluents provide adequate cryoprotection for the sperm of several mammalian species. Traditionally, chicken egg yolk has been used as additive for the freeze preservation of spermatozoa because of its wide availability. Variations in the chemical composition of the egg yolk of different avian species appear to influence the protection afforded during cooling, freezing, and thawing. The aim of the present study was to assess the use of quail egg yolk as a novel additive for the epididymal spermatozoa of a threatened wild ruminant species—the Spanish ibex—and to compare its efficacy with chicken egg yolk. Epididymal spermatozoa were diluted using a Tris–citric acid–glucose medium (TCG) composed of 3.8% Tris (w v⁻¹), 2.2% citric acid (w v⁻¹), 0.6% glucose (w v⁻¹), 5% glycerol (v v⁻¹), and 6% egg yolk (v v⁻¹). Sperm masses from the right epididymes were diluted with TCG-6% chicken egg yolk medium, while those from the left were diluted with TCG-6% quail egg yolk. The thawed spermatozoa preserved with TCG-6% quail egg yolk extender exhibited lower motility (P < 0.001), membrane integrity (P < 0.001), and viability (P < 0.01) than those diluted with the TCG-6% chicken egg yolk extender. The fertility of spermatozoa frozen in TCG-6% chicken egg yolk tended to be higher than in those frozen with TCG-6% quail egg yolk (63.3% vs 36.4%, P = 0.19). These results show that quail egg yolk offers no advantages over chicken egg yolk in the cryopreservation of Spanish ibex epididymal spermatozoa.     

Piglet use of the creep area—Effects of breeding value and farrowing environment

The objective of this study was to investigate piglet use of the creep area, comparing litters of sows with a high vs. low breeding value for piglet survival in the first 5 days postpartum, that were either housed in crates or individual pens during farrowing and lactation. Seventy-five Yorkshire × Danish Landrace sows were video recorded for 4 days after farrowing, and the analysis was conducted using instantaneous sampling every 10 min commencing 24 h after the birth of the first piglet for a period of 72 h. Breeding value for piglet survival had no effect on piglet use of the creep area or time spent in any location of the farrowing environment. Farrowing environment had significant effects on piglet location; during all days there were significantly more piglets in the creep area in the crates compared to the pens (P < 0.01), and this difference was larger at 24–48 h than at 49–72 h and at 73–96 h after birth (P < 0.05). Piglets in pens spent significantly more time resting near the sow, excluded nursing (P < 0.001), and this percentage decreased over time after farrowing (P < 0.001) in both the crates and the pens. In conclusion, piglet use of the creep area was higher in the crate compared to the pen particularly during the second day of life. This may partly be due to a much larger proportion of uncomfortable, slatted floor in the crates, and the shorter distance from the sow to the creep area in the crate.     

The effect of early human contact and the separation method from the dam on responses of beef calves to humans

The objectives of this experiment were to evaluate the effect of early human contact and of the separation method from the dam on the future relationships of calves with humans, and to investigate the relationship between dam responses and calf responses. Thirty-three Salers calves aged 2–4 days old and reared outdoors were split into 3-week treatments balanced according to sex and birth dates. Group 1 (long separation from the dam and human contact: LS + H; n = 11) underwent 8 h of separation from the dam per day and 5 min of individual stroking; group 2 (short separation from the dam and human contact: SS + H; n = 11) underwent 1 h of separation and the same amount of human contact as LS + H calves. Group 3 (short separation from the dam and no human contact: SS − H; n = 11) was a control group undergoing the same duration of separation as SS + H but without stroking. At 3, 15 and 45 weeks of age, the calves were tested in a standard arena test (AT) where they were successively left alone (2 min), left with a stationary human (5 min), and left with a human approaching and touching them (2 min). At 15 and 45 weeks, the calves were also tested with the standard docility test (DT: test of restraint). The dams were also tested with DT 2 months before calving. Data analysis via Mann–Whitney tests and Spearman's correlations showed no significant effect of the duration calves were separated from their dams. Just after treatment at 3-week of age, calves given stroking (LS + H and SS + H) were more motionless and more willing to accept human contact (AT: touching) than control calves (SS − H, P < 0.01). At 45 weeks of age, calves given stroking spent also significantly more time (P < 0.05) motionless with the approaching human compared to non-stroked calves (SS − H), suggesting a persistent effect. However, this effect was not reproduced on the other behavioural criteria recorded (e.g., duration of human contact or docility score). In the different tests and at the different ages, the docility scores of the dams were significantly correlated (up to 0.7, P < 0.01) with behaviour towards humans shown by stroked calves but not non-stroked calves (SS − H). Our results suggest that additional human contact at early age, but not duration of the separation from the dam, could be beneficial for the human–animal relationship, but only for calves born to docile dams.     

Physiological and behavioural responses of cows from two beef breeds submitted to different suckling strategies

This experiment was designed to study the effects of avoiding calf contact and genotype on the metabolic, behavioural and reproductive traits of beef cows during lactation. Fifty-two multiparous cows, 25 Parda de Montaña (PA) and 27 Pirenaica (PI), fed at maintenance were assigned from the day after calving to twice-daily nursing (2× 30-min sessions at 0800 and 1600 h) either with fence contact with their calves (partial contact, PC) or without visual, tactile and olfactory contact (non-contact, NC) between suckling periods. Blood samples were collected to analyse metabolites (triglycerides, cholesterol, non-esterified fatty acids (NEFA), β-hydroxybutyrate and urea) and progesterone at different intervals. Cow–calf behaviour was monitored on weeks 4, 9 and 15 of lactation. Cow activity at oestrus was recorded through collars. Cows from both treatments and breeds showed similar live-weight gains during the first three months post-partum (P > 0.10). Milk yield and calf gains were not affected by treatment (P > 0.10) but they were greater in PA than in PI (P < 0.05). Plasma triglycerides and urea in the cows were not affected either by calf contact, breed or week post-partum (P > 0.10). Plasma cholesterol increased from week 6 post-partum onwards in PA cows (P < 0.05) while this rise was delayed to week 7 of lactation in PI breed (P < 0.05). Plasma NEFA was greater in blood from PC–PA cows than in the rest of groups (P < 0.05), and these metabolites were greater on week 1 and lower on week 11 than in rest of samplings (P < 0.05). Plasma β-hydroxybutyrate was not affected by either calf contact or breed (P > 0.10), but it was greatest on weeks 1–3 than in the rest of lactation (P < 0.05). Cows with PC calves took less time to first contact after they entered the barn than their NC counterparts (P < 0.05). Dams from both contact treatments nursed their offspring and remained in close proximity for similar time within suckling periods (P > 0.10). PA cows devoted more time than PI ones to lick their young (P < 0.001). There were no differences throughout lactation in any of the studied maternal behaviours (P > 0.10). Calf contact and breed did not affect the interval to first post-partum ovulation or oestrus in these cows (P > 0.10). Under twice-daily nursing conditions, the limitation of visual, tactile and olfactory contact with calves did not trigger different maternal or reproductive traits in these breeds but only a slightly higher mobilisation of body fat substrates in Parda de Montaña compared to Pirenaica.     

Genotoxic effects of PCB 52 and PCB 77 on cultured human peripheral lymphocytes

Polychlorinated biphenyls (PCBs) are known to be carcinogenic, but the mechanisms of this action are uncertain. Most, but not all, studies have concluded that PCBs are not directly mutagenic, and that much if not all of the carcinogenic activity resides in the fraction of the PCB mixture that contains congeners with dioxin-like activity. The present study was designed to determine genotoxic effects of an ortho-substituted, non-coplanar congener, 2,2′,5,5′-tetrachlorobiphenyl (PCB 52), and a non-ortho-substituted coplanar congener with dioxin-like activity, 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) on cultured human peripheral lymphocytes. DNA damage was assessed by use of the comet assay (alkaline single-cell gel electrophoresis). After cell cultures were prepared, test groups were treated with different concentrations of PCB 52 (0.2 and 1 μM) and PCB 77 (1 and 10 μM) for 1 h at 37 °C in a humidified carbon dioxide incubator, and compared to a DMSO vehicle control group. The cells were visually classified into four categories on the basis of extent of migration such as undamaged (UD), low damage (LD), moderate damage (MD) and high damage (HD). The highest concentration of PCBs 52 and 77 significantly increased DNA breakage in human lymphocytes (p < 0.001). Our results indicate that both the non-coplanar PCB 52 and coplanar PCB 77 cause DNA damage, and that the ortho-substituted congener was significantly more potent than the dioxin-like coplanar congener.     

Social preferences in farmed silver fox females (Vulpes vulpes): Does it change with age?

Determining foxes’ social preference, and how this influences their social behaviour towards different conspecifics at different ages may give us a better understanding of how to prevent foxes from exposure of possible social stressors when housed in groups. Here, we investigated the effect of familiarity on social preferences in silver fox females and their motives for seeking social contact at two different ages. Fourteen silver fox females conducted two preference tests, first at the age of 9 weeks and the second at the age of 24 weeks, where they could choose between an empty cage, a familiar female or an unfamiliar female at their own age. The position and behaviour of the females were recorded using instantaneous sampling every tenth minute for 26 h. There was a clear preference to seek contact with a conspecific at 9 weeks of age (p < 0.01). The cubs did not differentiate between a familiar or unfamiliar stimulus animal (p > 0.05), however there was a tendency to play more in front of the unfamiliar stimulus animal (p = 0.07). No preference was seen for either the familiar, unfamiliar or empty cage stimulus when the females were 24 weeks old (p > 0.05), however they were more aggressive towards the unfamiliar stimulus animal (p < 0.01). Thus, there was no effect of familiarity in time spent with a social stimulus at either age, however these results suggest that the motives for seeking contact as cubs were non-aggressive and possibly play related, whereas the aggressive behaviour displayed by juveniles towards the unfamiliar female indicates an increased competitive motivation.     

Intake, rumen fermentation and nutrient flow to the omasum in beef cattle fed grass silage fortified with sucrose and/or supplemented with concentrate

The objective was to determine the relative effects of a specific increase in grass silage sucrose concentration, or a specific supplement of a starch-based concentrate, on rumen fermentation and nutrient supply to the omasum in beef cattle. Four ruminally cannulated Holstein–Friesian steers were fed grass silage only (G), G plus 3 kg concentrates/day (GC), G plus 90 g sucrose/kg dry matter (DM) (GS) and G plus 90 g sucrose/kg DM plus 3 kg concentrates/day (GCS) in a 4 × 4 Latin Square design experiment. Omasal flow was estimated using Co-EDTA, Yb-acetate and indigestible neutral detergent fibre (INDF) as digesta flow markers and purine bases as microbial markers. Concentrate supplementation reduced (P < 0.01) silage and increased (P < 0.001) total DM intake whereas sucrose had no effect. There was a sucrose × concentrate interaction (P < 0.05) for rumen pH whereby addition of sucrose to grass silage alone decreased pH and to grass silage plus concentrate had no effect. Rumen ammonia N (P < 0.01), total volatile fatty acid (VFA) concentration (P < 0.05) and the molar proportions of valerate (P < 0.05) and butyrate (P < 0.001) increased with concentrate supplementation whereas, sucrose supplementation had no effect on rumen fermentation parameters. Organic matter (OM) intake, omasal OM flow, the quantities of OM apparently (OMAD) and truly digested (OMTD) in the rumen (P < 0.001) and total tract OM digestibility (P < 0.01) increased, and apparent and true ruminal OM digestibility decreased (P < 0.05) with concentrate supplementation. Supplementation with concentrate decreased (P < 0.05) ruminal neutral detergent fibre (aNDFom) digestibility and increased (P < 0.05) aNDFom omasal flow. There was a tendency for addition of sucrose to increase (P < 0.1) ruminal OMAD and OMTD, while there was no effect of sucrose addition on intake or digestion of aNDFom. Concentrate supplementation increased (P < 0.001) N intake, flows of N, non-ammonia N (NAN), microbial N (MN) (P < 0.05) and non-ammonia non-microbial N (NANMN) (P < 0.01) and apparent total tract digestibility of N (P < 0.01), whereas sucrose reduced (P < 0.05) N intake and apparent ruminal N digestibility. There was no effect of concentrate or sucrose on N use efficiency or efficiency of microbial protein synthesis. Concentrate supplementation increased (P < 0.001) plasma β-hydroxybutyrate levels. In comparison to supplementing unwilted, well preserved grass silage of moderate digestibility with 3 kg starch-based concentrate per day, the limited response to the rate of sucrose supplementation employed suggests that increasing the water-soluble carbohydrate (WSC) concentration of grass silage through agronomic and/or ensiling practices will have relatively little effect on intake, rumen digestion or efficiency of microbial N synthesis.     

Both substrate availability and utilisation contribute to the defence of core temperature in response to acute cold

Acute cooling significantly increases energy demand in non-hibernators for the defence of core temperature but the contribution of the liver to thermogenesis is poorly understood. A two-tracer method to estimate lipid metabolism in cold-naïve control (CON) and cold-acclimated (CA) rats was employed to quantify hepatic rates of fat metabolism. Both fenofibrate, to increase liver mass and fat oxidation and dichloroacetate (DCA) to inhibit fat oxidation were used to alter lipid metabolism in CON animals. Following acute cooling, CA led to a doubling of the time to reach a core temperature 25 °C (P < 0.001), whereas DCA treatment decreased time of cooling (P < 0.01). DCA-treatment increased the gradient of Arrhenius-transformed rate–pressure product (P < 0.01). CA increased both palmitate uptake (P < 0.001) and β-oxidation (P < 0.01) whilst DCA treatment decreased uptake (P < 0.01) and β-oxidation (P < 0.05). Tissue-specific estimates of metabolism revealed that CA led to a 12-fold increase in β-oxidation for brown adipose tissue (P < 0.001) whilst fenofibrate halved β-oxidation in the liver (P < 0.01) despite doubling the liver mass (P < 0.001) and DCA decreased hepatic β-oxidation to 15% of control levels. Taken together, these results suggest that the liver has minimal contribution to thermogenesis in the rat, with brown adipose tissue significantly increasing both fat uptake and oxidation in response to CA.     

Effects of sex, litter size and periconceptional ewe nutrition on the ewe–lamb bond

Undernutrition restricted to the time around conception in sheep alters endocrine and metabolic responses in the offspring. Studies in rats suggest that such an early insult can also alter the behaviour of the offspring. We studied the effects of mild maternal periconceptional undernutrition (10–15% body weight reduction) on the lamb's response to separation from and reunion with the mother, and on the ewe–lamb bond, evaluated as the preference for each other over an alien ewe/lamb in a test enclosure, at 24 h, 1 and 4 weeks of age. Lamb birth weight was not affected by maternal nutrition. Maternal periconceptional undernutrition did not affect the lambs’ responses to separation and reunion (number of vocalisations, times to leave pen and achieve proximity with ewes) or the bond between ewes and lambs (percentage of time spent near their own dam/lamb). However, there were effects of sex, litter size and time on lambs’ responses to separation and reunion and on the ewe–lamb bond. Female lambs vocalised more during separation (P ≤ 0.01) and left the holding pen faster than males (P ≤ 0.05), and twins vocalised more than singletons (P ≤ 0.05). The time to leave the holding pen, achieve proximity with the ewes and number of vocalisations decreased with increasing postnatal age of the lamb (all P ≤ 0.001). Ewes showed a stronger preference for the lamb at 24 h and 1 week than at 4 weeks postpartum (P ≤ 0.001), whereas lambs followed an opposite trend, showing a lower preference for the mother at 24 h and 1 week and increased preference at 4 weeks of age (P ≤ 0.001). We conclude that periconceptional undernutrition does not affect offspring response to separation from the mother or the bond between ewes and lambs, but that these behaviours are affected by sex and litter size for up to 4 weeks after birth.     

Influence of access to straw provided in racks on the welfare of sows in large dynamic groups

This experiment investigated the effect of providing access to straw in racks on the welfare of sows in large dynamic groups. Two treatments were applied: (1) access to two racks containing chopped barley straw (offering an average of 0.3 kg straw/sow/day) and (2) control, with no straw racks. Treatments were applied to two separate dynamic groups each containing 35 (±3) sows. Approximately 9 sows were replaced in each of these groups at 3-week intervals (each replacement constituting a replicate of the study). Peak rack usage was shown between 08:00 and 12:00 h, where on average 6% of sows were observed at each rack. On average over a 24-h period, 27% of sows that were observed at the racks were newly introduced. This percentage was significantly greater in the pre- rather than post-feeding yard (P < 0.05). On average over a 24-h period, a greater average percentage of sows was observed at the post- rather than pre-feeding rack (P < 0.001). Observations of resident pen behaviour showed that sows with access to straw spent approximately 9% of their time exploring the racks. Sows in the straw treatment spent a significantly lower percentage of time exploring the floor (P < 0.05). Reductions were also shown in general exploratory behaviour in the straw treatment (P < 0.05). Overall levels of aggressive behaviour were low, however significantly greater levels were shown in the straw treatment (P < 0.05). Injury scores did not differ significantly between treatments (P > 0.05). A greater proportion of sows performed sham chewing behaviour in the post- rather than the pre-feeding yard (P < 0.01). However, average levels of sham chewing behaviour did not differ significantly between treatments (P > 0.05). Overall, providing access to straw in racks led to a reduction in pen-directed exploratory behaviour, and this may reflect the fact that sows were provided with an outlet for exploratory and/or foraging behaviour. However, the fact that sham chewing behaviour was not affected suggests that welfare benefits associated with the straw rack treatment were limited.     

A note on the effectiveness of behavioural rehabilitation for reducing inter-dog aggression in shelter dogs

The effectiveness of a rehabilitation program for reducing inter-dog aggression was evaluated at the municipal animal shelter. Sixteen dogs (of 60 examined) met the study criteria of medium inter-dog aggression as determined by an inter-dog aggression test. These dogs received a 10-day treatment of daily rehabilitation for 30 min (rehabilitation group, n = 9) or daily release into an outdoor enclosure for 30 min (control group, n = 7). Rehabilitation consisted of desensitising and counter-conditioning dogs to the approach of other “stimulus” dogs. Most dogs in the rehabilitation group showed a decline in aggression scores when re-tested after the last treatment (day 11), and differed significantly from the control dogs which showed either an increase or no change in aggression scores (U = 8.5, P < 0.01). Rehabilitation dogs also showed lower frequencies of aggressive body postures (“facing the stimulus dog”, P < 0.05, and “stiff posture”, P < 0.10) and higher frequencies of less assertive postures (“ears back”, P < 0.05, and “lowered neck”, P < 0.10) on day 11. The differences between groups were no longer significant when a reduced sample of dogs was tested 1 week after rehabilitation ended (day 18). The study shows short-term reduction of inter-dog aggression through rehabilitation, but further work is needed on effective ways of maintaining the behavioural change.     

Effect of conjugated linoleic acid on dietary lipids utilization, liver morphology and selected immune parameters in sea bass juveniles (Dicentrarchus labrax)

Increased energy content in fish feeds has led to an enhanced fat deposition, particularly in European sea bass, concerning fish farmers. Inclusion of conjugated linoleic acid (CLA) could reduce fat deposition as in other vertebrates. To determine if dietary CLA affects fat deposition, lipid metabolism, lipid composition and morphology of different tissues, growth and selected immune parameters, European sea bass juveniles were fed 4 graded levels of CLA (0, 0.5, 1 and 2%). Growth and feed conversion were not affected by CLA, whereas feed intake was reduced (P < 0.05) by feeding 2% CLA. In these fish perivisceral fat was also reduced (P < 0.05), particularly reducing (P < 0.05) monounsaturated fatty acids. CLA has not affected tissue proximal composition, but reduced (P < 0.05) saturated and monounsaturated fatty acids and increased (P < 0.05) the n−3 and n−3 highly unsaturated fatty acids in muscle and increase (P < 0.05) CLA content in muscle, liver and perivisceral fat. A progressive reduction in lipid vacuolization of hepatocytes cytoplasm and regular-shaped morphology was found in fish fed increased CLA levels, together with a progressive increase in malic enzyme activity (only significant in fish fed 1% CLA). Finally, inclusion of CLA up to 1% increased (P < 0.05) plasma lysozyme activity and was positively correlated with alternative complement pathway.     

Effect of individual or paired housing during post-weaning on feed intake, growth rate and behaviour of lambs

The aim of this study was to compare the behaviour and weight gain of weaned lambs penned either in pairs or alone, with visual and tactile contacts between pens. A 2 × 2 factorial experiment was conducted over seven weeks. Forty-eight Dorset lambs (twenty-five females and twenty-three males) were randomly distributed among pens. All pairs were non-twin lambs of the same sex. They were fed haylage (48.9% of DM) and a commercial pelleted feed both provided ad libitum. Weight of lambs was recorded at d0 and then weekly until d49. Consumption of dry matter and average daily gain (ADG) were also recorded. Lamb postures, activities and total bleats were directly observed in the morning and in the afternoon on six different days (d1, d2, d5, d12, d19, d26). On d1, observations were done only in the afternoon. For paired lambs, data were averaged by pen. Lambs penned alone were less active, slept more (P < 0.03) and walked less (P < 0.001) than paired lambs. Total bleats were not affected by housing treatment or sex, but were significantly higher for the first two days (P < 0.0001). Lamb growth performance was unaffected by the type of housing (P > 0.05). There was a significant difference in ADG (P < 0.001), total gain (P < 0.001), kg concentrate kg⁻¹ gain (P < 0.05) and final body weight (P < 0.05) in favor of males as compared to females. Our results suggest that a housing system in which individually raised lambs are allowed visual, tactile, and auditive contact with each other, compared to lambs housed in pairs, does not impact negatively on their growth and behaviour.     

Survivin protein expression in bovine follicular oocytes and their in vitro developmental competence

This study examined the relationship between survivin expression and the stage of development of in vitro cultured bovine oocytes and embryos; and whether survivin expression is affected by the quality of cumulus–oocyte complexes (COCS) or the quality of pre-implantation embryos. A polyclonal antibody was prepared using recombinant bovine survivin protein. Expression of survivin mRNA and protein was analyzed by real-time quantitative RT-PCR and immunocytochemistry. In the first experiment, survivin mRNA expression was examined at developmental stages from germinal vesicle (GV) oocyte to blastocyst, it was significantly decreased after fertilization of matured oocytes (P < 0.05), then increased slightly to the 8-cell stage followed by rapid increases at the morula and blastocyst stages (P < 0.05). In the second experiment, the effect of oocyte quality on survivin protein, pro-apoptotic (bax, caspase-3) and anti-apoptotic (survivin, bax inhibitor) mRNA expression was examined. Survivin protein was more strongly expressed in good quality COCS than in poor quality COCS. The expression of the anti-apoptotic genes, survivin and bax inhibitor, was significantly higher (P < 0.05) and that of the pro-apoptotic genes, bax and caspase-3, was significantly lower (P < 0.05) in good compared to poor quality COCS. The developmental competence of good quality COCS (30.4% blastocysts) was significantly better than that of poor quality COCS. In the last experiment also, we confirmed that significantly higher expression of survivin and bax inhibitor genes and significantly lower expression of bax and caspase-3 genes was resulted in good quality blastocysts than in poor quality blastocysts (P < 0.05). It was concluded that the expression of survivin was related to the quality of COCS, their developmental competence and the quality of in vitro produced blastocysts. Consequently, survivin may be a good candidate marker for embryo quality.     

Maturation of the intestinal digestion and of microbial activity in the young rabbit: impact of the dietary fibre:starch ratio

The developmental changes of intestinal digestive potential and caecal microbial activity were described in suckling and weaned rabbits according to two feeding programmes. Two groups of thirteen litters were fed from 18 to 42 days old a “High” or a “Medium” NDF:starch ratio diet (resp. 2.7 vs 2.0, groups HL and ML) with similar protein and lipid levels, and from 42 to 70 days old the two groups were fed a “Low” NDF:starch ratio diet (1.7). From 25 to 32 days (weaning), the milk and solid feed intake were 22% and 41% higher in ML group (P < 0.05), and the mortality by diarrhoea was 4 units lower (P < 0.01). The whole tract digestive efficiency increased by 10% before weaning, and remained steady (organic matter) or decreased (lipids, protein) after weaning. Energy digestibility was 0.623 and 0.686 for High and Medium diets respectively. From 25 to 42 days, total enzymatic activity in intestinal content increased for chymotrypsin (5-fold, P < 0.001), lipase (10-fold, P < 0.001), amylase (17-fold, P < 0.01) and maltase (11-fold, P < 0.001), while trypsin doubled after weaning. The feeding programme only affected the amylase and maltase activities, that were higher in HL group (P < 0.05). The volatile fatty acids concentration in the caecum was not significantly different among the groups, but it increased by 44% 10 days after weaning. The bacterial fibrolytic enzymes, increased by 30% after weaning and were similar among the two groups. The study revealed that the intestinal digestive maturation and the caecal microbial activity of the rabbit evolved markedly between 3 and 5 weeks of age, and was weakly affected when the NDF:starch ratio decreased from 2.7 to 2.0.     

Comparison of the effects of two different handling methods on the subsequent behaviour of Anglo-Arabian foals toward humans and handling

Tactile contact is often used to improve the human–foal relationship, in particular during sensitive periods such as weaning. However, the method used to provide the contact (forced or unforced) may affect subsequent reactions to humans. The aim of our study was to compare the effect of forced and unforced handling at weaning on horses’ behaviour towards humans and handling.A total of 23 Anglo-Arabian foals received individual human contact at weaning. Constrained-handled foals (forced human contact; FC, n = 8) were stroked while being restrained (i.e., held by the halter without being led) so that human contact was forced. Unconstrained-handled foals (unforced human contact; UC, n = 7) were stroked without any restraint and could thus avoid contact if they so wanted. Each individual was handled 5 min twice a day for 14 consecutive days. Control foals were not handled (no contact; NC, n = 8). Foals’ reactions towards a human (e.g. proximity and contact seeking), and their manageability (fitting of a halter) were then assessed. The animals from the different treatments were then mixed and tested again 4 months later. Non-parametric Mann–Whitney U-tests were used to compare experimental groups.Only forced human contact reduced fear reactions toward humans (e.g. shorter latency to approach a passive human, P < 0.01; shorter latency to touch the foal, P < 0.05) in the short-term (immediately after the handling sessions) and increased foals’ manageability in a familiar environment (shorter latency to be placed a halter on and less defences displayed, P < 0.05). It had no effect in an unfamiliar environment. These effects did not last longer than 4 months.Forced human contact thus appears to be more efficient in improving human–horse relationships and subsequent handling than unforced human contact. However, the lack of effect on reactivity towards humans in an unfamiliar environment, and the lack of long-term effects suggest that this method needs to be improved to be more effective. Some of our results suggest that horses could perceive human contact (i.e., stroking) as positive, however further studies are needed to confirm this hypothesis.     

Influence of exogenous enzymes on nutrient digestibility, extent of ruminal fermentation as well as milk production and composition in dairy cows

This experiment studied effects of a mixture of exogenous enzymes (ZADO^®) from anaerobic bacteria on ruminal fermentation, feed intake, digestibility, as well as milk production and composition in cows fed total mixed rations (TMRs; 0.7 corn silage and 0.3 of a concentrate mixture). Twenty lactating multiparous Brown Swiss cows (500 ± 12.4 kg live weight) were randomly assigned into two experimental groups of 10 immediately after calving and fed a TMR with or without (CTRL) addition of 40 g/cow/d of enzymes for 12 weeks. Addition of enzymes increased (P<0.05) rumen microbial N synthesis. Intake of dry matter (DM) and organic matter (OM) was positively influenced (P<0.05) by supplementation, and digestibility of all nutrients was higher (P<0.05) in the total tract of supplemented cows, although the magnitude of the improvement varied among nutrients, with the highest improvement in aNDFom and ADFom (418–584 and 401–532 g/kg respectively; P<0.05) than the other nutrients. Supplementation of enzymes also increased (P<0.05) rumen ammonia N and total short chain fatty acid (SCFA) concentrations, and individual SCFA proportions were also altered with an increase in acetate (61.0–64.8 mol/100 mol; P=0.05) before feeding, and acetate and propionate increased 3 h post-feeding (60.0–64.0 and 18.3–20.8 mol/100 mol respectively; P<0.05). Milk and milk protein production was higher (12.8–15.7 and 0.45–0.57 kg/d respectively; P<0.05) for cows fed the ZADO^® supplemented diet. This exogenous enzyme product, supplemented daily to the TMR of cows in early lactation, increased milk production due to positive effects on nutrient intake and digestibility, extent of ruminal fermentation and microbial protein synthesis.     

Micronuclei in diabetes: Folate supplementation diminishes micronuclei in diabetic patients but not in an animal model

Diabetes mellitus (DM) is associated with a high risk of health complications, mainly due to excessive free radical (FRs) production that could result in an increased frequency of micronuclei. The consumption of antioxidants, like folic acid (FA), may mitigate the effects of the FRs. In the present study, micronucleated polychromatic erythrocyte (MNPCE) frequencies were determined in blood sampled weekly from the tails of pregnant female Wistar rats and pregnant Wistar rats with experimental diabetes that were given unsupplemented diets and diets supplemented with FA. At birth, the pups were sampled to analyze micronucleated erythrocyte (MNE) and MNPCE frequencies. Moreover micronucleated cells (MNCs) were evaluated in buccal mucosa samples taken from 81 healthy adult subjects, 48 patients with DM, and 30 DM patients who were sampled before and after FA treatment. Increases in MNPCE frequencies were significant only at the first sampling (P < 0.01 and P < 0.03) in pregnant rats with experimental diabetes. In addition, the pups from the diabetic group and from diabetic group treated with FA had higher frequencies of MNEs (P < 0.03 and P < 0.001, respectively) and MNPCEs (P < 0.009 and P < 0.05, respectively) than the controls. No differences were found in diabetic rats and newborn rats born to diabetic mothers treated with FA compared with untreated animals. Patients with DM had a higher frequency of MNCs compared with healthy subjects (P < 0.001). Also FA reduced the frequency of MNCs in DM patients (P < 0.001). The results of this study indicate that diabetes results in elevated frequencies of micronuclei, and that, at least in humans, FA can protect against the elevation.     

Effect of maternal fatness on fetal steroids and semi-quantitative real-time PCR expression of receptor genes in sheep

Sexual differentiation of the brain occurs between d 30 and 70 in the fetal lamb. The objective of this experiment was to determine if maternal fatness affects fetal steroid production and expression of their receptors which may ultimately alter endocrine systems postnatally. Fetuses were collected from ewes fed at either 100% (Control; n = 5) or 150% (Fat; n = 6) of NRC recommendations from 60 d prior to breeding until collection at 75 d of gestation. Hypothalamic and amygdala neural tissues were collected from twin male/female fetuses. Serum concentrations of testosterone were greater (P < 0.001) in male fetuses compared to female fetuses. Further, male fetuses from Fat ewes had greater (P < 0.05) serum concentrations of testosterone than male fetuses from Control ewes, but differences in testicular steroidogenic enzyme mRNA were not detected (P = 0.18). Quantity of hypothalamic mRNA for estrogen receptor (ER) β tended (P = 0.1) to be influenced by a sex by treatment interaction. Messenger RNA for ER-β was greater in female fetuses than male fetuses from Control ewes (P = 0.05). Although amount of ER-β mRNA did not differ among male fetuses (P = 0.7), amounts tended to be less (P = 0.07) in female fetuses from Fat ewes compared to those from Control ewes, and did not differ (P ≥ 0.8) from male fetuses. Hypothalamic ER-α mRNA tended (P = 0.1) to be less in fetuses from Fat ewes compared to Control fetuses but was not influenced (P = 0.3) by fetal sex or their interaction. Amount of mRNA for hypothalamic progesterone receptor tended (P = 0.06) to be greater in male fetuses than female fetuses and tended to be less (P = 0.06) in fetuses from Fat ewes than in Control fetuses, but did not differ by any sex by treatment interaction (P = 0.6). Hypothalamic RNA for the androgen receptor did not differ by sex, dam nutritional treatment, or the interaction. Likewise, amygdala RNA for the estrogen or androgen receptor did not differ (P ≥ 0.3) by sex, treatment, or their interaction. Dam fatness appears to decrease the expression of progesterone receptor, ER-α, and decrease amount of ER-β in the female fetuses while increasing circulating concentrations of testosterone in male fetuses. Altered expression of hypothalamic receptor genes by the uterine environment may affect adult responses to stress, sexual behavior and/or the pattern of gonadotropin release in response to gonadal steroids.     

Influence of level of zilpaterol chlorhydrate supplementation on growth performance and carcass characteristics of feedlot lambs

Forty-eight Pelibuey × Katahdin (38.8 ± 0.67 kg) crossbred male lambs were used in a 32-day feeding trial (four pens per treatment in a randomized complete block design), to evaluate the influence of zilpaterol (β₂-agonist) supplementation level on growth performance and carcass characteristics. Lambs were fed a dry-rolled corn-based finishing diet (3.04 Mcal/kg of ME) supplemented with 0, 0.15, 0.20, or 0.25 mg/kg of live weight d⁻¹ zilpaterol (as zilpaterol chlorhydrate, Zilmax^®, Intervet México, México City). DM intake averaged 1.099 ± 0.042 kg/d and was not affected (P = 0.40) by treatments. Compared with control lambs, zilpaterol supplementation increased gain efficiency (15.8%, P < 0.03), apparent energy retention per unit DMI (10.9%, P = 0.03), and tended to increased daily gain (16%, P < 0.07) and total gain (17.7%, P < 0.08). Zilpaterol supplementation did not affect (P = 0.20) carcass weight, longissimus muscle area (LM), or fat thickness, but increased (2.3%, P = 0.04) carcass dressing percentage and reduced (36%, P < 0.01) kidney-pelvic fat. Increasing level of zilpaterol supplementation increased total weight gain (linear component, P < 0.05), gain:feed (linear component, P < 0.01), and dressing percentage (linear component, P < 0.02), and decreased (linear component, P < 0.01) kidney-pelvic fat. We conclude that zilpaterol supplementation enhances growth performance and dressing percentage in lambs in a manner comparable to that of cattle (greater muscle accretion, reduced body fat). Responses to zilpaterol was optimal when supplemented at 0.20 mg of zilpaterol/kg of live weight d⁻¹.