The effects of day length, of the daily change in day length and of heat load, together with age effect, on live-weight gain of Holstein-Friesian bull calves, were studied using 8205 gain records of 1019 calves that were maintained in the experimental herd at Newe Ya'ar during a 5-year period (1991 to 1995). The age range of the calves was 150 to 450 days. Effects of day length (h) and of day length change (min/day) were assumed to be linear and effect of age was assumed to be quadratic. Three heat load indexes were calculated, accounting for day temperatures above 27°C, or night temperatures above 18°C, or both, and their effect was assumed to be linear also. Random effect of calf and fixed effect of the year were also accounted for by the regression analysis. The mean gain was 1·274 kg/day. The effect of day length was 0·027 (s.e. 0·003) kg/day per h, and effect of day length change was 0·042 (s.e. 0·003) kg/ay per min/day both effects being highly significant (P < 0·0001). The effects of heat load according to each of the three indexes were either not significant, or tended to be positive, which implies increased gain with increasing heat load. Effect of age was positive (P = 0·0005), and of age2 was negative (P < 0·0001). Based on the regression model that did not include heat load effect, the peak gain was obtained on 19 May, 33 days before the longest day and the trough was obtained on 18 November, with a difference of 0·206 kg/day (proportionately 0·15 of the peak gain) between peak and trough gains. It was calculated by the regression coefficients for the photoperiod effects, that a calf that enters the feedlot at the age of 150 days and a live weight of 180 kg on 1 January, will be 23 kg heavier at the age of 350 days than a calf that enters the feedlot at the same age and weight on 1 July. This difference is reduced to 10 kg at the age of 450 days.

Female reproductive performance over four parities was studied for lines of mice selected for one three criteria: appetite (A), total lean mass (P), or proportion of fat (F). Female mice were first bred 8 weeks of age, and thereafter at intervals of about 7 weeks until fourth parity when they were dissected in late pregnancy to measure components of litter size.

The high A lines had higher litter sizes at the first three parities and higher ovulation rates, numbers of implantation sites and live foetuses at the fourth parity than the low A lines. The high P lines were also higher than the low P lines for each of these traits. In contrast, litter sizes and ovulation rates differed little between the high and low F lines. Fitting body weight as a covariate removed the high-low differences in ovulation rate and litter size between the P lines, but not all the differences between the A lines.

Pre-implantation survival at the fourth parity was slightly lower in the high than in low A and in high than in low P lines. Differences in post-implantation survival were very small. No component of prenatal survival differed substantially at fourth parity between the high and low F lines.

Differences in fertility at each parity and the percentages of females surviving to the end of the study were small. At each litter, dams of the high A lines produced heavier total weights of litters at 12 and 21 days than dams of the low A lines and the corresponding high-low differences in the P lines were larger. There were only small differences in these traits between the F lines. When litter size, fertility and survival were summed over parities, the average total number of young produced per female was substantially higher in the high than in the low A lines (5·0 young born alive or dead) and the P lines (7·2), but the high-low difference was small in the F lines (2-0). For all lines, litter size at first parity gave a reliable indication of reproductive rate during a major portion of the reproductive lifespan.

One of the major limitations to the widespread use of artificial insemination (AI) in the United Kingdom (UK) sheep industry is that with frozen-thawed semen current insemination techniques result in lowered fertility. Consequently, only fresh or liquid-chilled ram semen can be used if commercially acceptable conception rates are to be achieved.

The relationship between the composition of the fat-free carcass and carcass fatness was studied by considering the relationship as one between two shape vectors, with the effect of size removed, using an extension of the multivariate linear least squares technique for studying multivariate allometry.

In two sets of data, one of dressed carcasses of cattle and the other of empty carcasses of lambs, the composition of the fat-free carcass (in terms of protein, water and ash) was significantly related to carcass fatness (P < 0·10 and P < 0·05 respectively). The consequences of this relationship to the study of the chemical composition of carcasses are discussed.

Examination of the relationship in more detail showed that the fatter carcasses were those with more protein and less water in their fat-free carcass, in both sets of data, and with more ash in the empty carcasses of lambs.

The use of modern prolific lines of rabbit does in intensive production systems leads to an increase in productivity but also causes a rise in several problems related to the does’ health status. Hence, the aim of this study was to investigate the effect of the litter size on the metabolic, inflammatory and plasma amino acid profile in rabbit does. The blood of 30 pregnant does was sampled on the 27th day of pregnancy. The does were retrospectively grouped according to the number of offspring into a high litter size group (HI, does with ≥ 12 kits; n = 16) and a low litter size group (LO, does with ≤ 11 kits; n = 14). Data were subjected to Pearson’s correlation analysis. Further, data were analysed in agreement to a completely randomized design in which the main tested effect was litter size. The linear or quadratic trends of litter size on parameters of interests were post hoc compared by using orthogonal contrasts. In addition, compared with the LO group, the HI group had lower levels of glucose (−5%; P < 0.01), zinc (−19%; P < 0.05), albumin (−6%; P < 0.05) and total cholesterol (−13%; P < 0.07), but the total bilirubin level was higher in the HI group (+14%; P < 0.05). Regarding the plasma amino acids, the HI group had lower concentrations of threonine (−15%), glycine (−16%), lysine (−16%) and tryptophan (−26%) and a higher level of glutamic acid (+43%; P < 0.05) compared with the LO group. The exclusively ketogenic amount of amino acids was lower (P < 0.06) in the HI (55.8 mg/100 ml) does compared with the LO does (56.8 mg/100 ml). These results show that a few days before delivery, rabbit does that gave birth to a higher number of offspring had a metabolic profile and an inflammatory status that was less favourable with respect to does who gave birth to a lower number of offspring. Moreover, the plasma amino acid profile points out that there was an enhanced catabolic condition in the rabbit does with a high number of gestated foetuses; it was likely related to the greater energy demand needed to support the pregnancy and an early inflammatory response.

The aim of this study was to investigate thyroid hormone levels in horses stabled in two different locations on the island of Sicily. The study was carried out on a total of 72 clinically healthy Sanfratellano horses ranging in age from 5 to 9 years and weighing 585 ± 40 kg. The results showed higher thyroxine values (P < 0.02) in horses stabled in an endemic goitre area (group II) than those observed in horses in a non-endemic area (group I). Unexpectedly, the T4/T3 and the fT4/fT3 rations were both lower in group I than in group II. The percentages of fT4 to T4 and of fT3 to T3 were both higher in group I than the percentages for group II. On the basis of gender, comparison between the two groups showed higher T4 (P < 0.01) and fT4 levels (P < 0.001) in males, and lower fT3 (P < 0.001) and fT4 levels (P < 0.005) in females stabled in the goitre endemic area. On the basis of age, younger horses (<7 years old) showed the highest thyroid hormone levels in both groups. Results suggest a physiological adaptive response of the equine species to an endemic goitre environment. The possibility that hypothyroidism is present in these horses is thus excluded and is supported not only by the lack of clinical signs, but also by the rarity of cases previously reported.

Four diets containing either 0 or 50 g fat per kg were prepared from a basal mix of barley, sugar-beet pulp, soya-bean meal and molasses. The fats used were tallow (saturated), soya-acid oil (unsaturated), or a 45:5 mixture of both fats. The diets were given with chopped dried grass to adult wether sheep in the ratio 4:1 of diet to dried grass. Measurements of heat production of the sheep were made in closed-circuit respiration chambers and from the data the efficiencies of utilization of energy for maintenance (km) and production (kf) were calculated for each diet, together with the metabolizable energy (ME) values for the fats.

Values for both km and kf were not significantly different between diets, the means were 0·81 and 0·61 respectively. The ME values (MJ/kg DM) of the fats were for tallow 36·2, for soya-acid oil 36·6 and for the tallow/soya mixture 31·6; these values were not significantly different.

No evidence of any synergistic effect caused by the addition of an unsaturated fat to a saturated fat was seen in this experiment.

Work in the United States of America has shown that dietary supplements of nickel (Ni) can result in an increase in rumen urease activity and can increase growth rate and food conversion efficiency in lambs and steers given low protein diets. It has been suggested that Ni enhances urea recycling through its effect on urease activity. To examine this hypothesis, four sheep were given a high-energy, lowprotein diet with or without a supplement of 5 mg/day Ni, given as NiCl2.6H2O by continuous infusion into the rumen. Urea irreversible loss rate (ILR) and pool size were measured by means of a single intravenous injection of 14C-urea. The addition of Ni resulted in a significant increase in rumen urease activity (P < 0·05) but there was no significant effect on urea ILR, urea pool size, urinary urea excretion or on the quantity of urea recycled to the gastro-intestinal tract. Ni also had no effect on plasma urea or rumen ammonia concentrations, on diet digestibility or on nitrogen retention. It is concluded that the enhancement of urease activity by supplementary Ni conferred no nutritional advantage to the sheep.

Two digestion trials were conducted using sheep fed whole grains of triticale, wheat or maize on an equal amount or an isonitrogenous basis. Nine ewes were used in a 10-day collection period for each trial. Both trials consisted of three treatment groups of three animals each. Each ewe received daily either 1200 g of a diet containing 740 g (per kg diet) triticale, wheat or maize (trial 1) or 900 g of a diet containing 650, 650 and 600 g (per kg diet), respectively, of the above grains. Digestibilities of various nutrients, dry matter and organic matter were generally similar among treatments. However, apparent digestibility of crude fibre was significantly higher for ewes fed triticale than for those fed maize or wheat diets.

In six experiments carried out on individually penned Finn Dorset ewes estimates were made of the quantities of non-ammonia nitrogen (NAN) reaching the abomasum and truly digested in the small intestine. For experiments 1 and 2 which each involved 33 ewes given a complete diet of milled hay and concentrates supplemented with varying amounts of a good-quality fish meal during late pregnancy, the overall regression estimate for the daily amount of truly digested NAN required for zero N retention (ewe plus conceptus) was 438 mg/kg M0·75 (441 and 434 for experiments 1 and 2 respectively). The coefficients for the efficiency of utilization of increments of truly digested NAN and maternal tissue N for net N accretion in the conceptus were 0·48 (s.e. 0·039) and 0·84 (s.e. 0·127) respectively.

In experiment 3, 24 lactating ewes had their diet supplemented with either soya-bean meal or fish meal. There was no effect of protein source on the amounts of NAN reaching the abomasum in ewes fitted with an abomasal cannula or on milk yield and these observations confirmed the unusually high degradability (measured by the polyester bag technique) of the fish-meal protein in the rumen. For experiments 4, 5 and 6 a total of 36 ewes were used to test the efficiency with which the NAN truly digested in the small intestine was used for the synthesis of milk protein. In the absence of data on the possible contribution of body tissue N to milk N the coefficient for the apparent efficiency of utilization of truly digested NAN when the ewes were given a basal diet containing approximately 10 g crude protein per MJ metabolizable energy was 0·63. For those ewes receiving the basal diet supplemented with either soya-bean meal, fish meal or blood meal the coefficients for the efficiency of utilization for the production of milk N of the increments in truly digested NAN supplied by the three protein sources were 0·61, 0·54 and 0·29 respectively. It is suggested that the low coefficient for blood meal may be due to its low content of methionine.

The rôle of growth hormone (GH) in normal growth is well established, but its rôle during recovery after live-weight loss in adults is less defined. This study examined the interaction of endogenous GH with energy or protein supplements during re-feeding of ewes in low body condition. Control ewes and ewes immunized against growth hormone-releasing hormone were housed in individual pens and given food below maintenance for 107 days, before re-feeding was initiated by supplementing half of each group with either fish meal or barley for 28 days (P1), after which the supplements were switched for a further 28 days (P2). Following supplementation, the ewes grazed abundant green pasture for 92 days before slaughter. Immunization reduced plasma concentrations of GH, insulin, insulin-like growth factor 1 (IGF-1) and prolactin. Production responses to the two food supplements were similar in the control and immunized ewes, but when grazed at pasture immunized ewes gained live weight more slowly (P = 0·06), grew less wool (P<0·01), and had heavier fat depots, but lighter carcass, skin and liver weights at slaughter. The sequence of re-feeding treatments affected subsequent wool production in both control and immunized ewes. During P2, and for 52 days after supplementation ceased, ewes supplemented with fish meal then barley (F/B) produced less wool (P < 0·05) than those supplemented with barley followed by fish meal (B/F). At slaughter, the F/B ewes had lighter omental and kidney fat depots than the B/F ewes (P < 0·05). It is concluded that during live-weight regain, endogenous GH initially affected fat deposition, which in turn affected food intake and wool growth. Furthermore, provision of supplements with a high protein to energy ratio to sheep in low body condition, followed by supplements with a low protein to energy ratio, caused a prolonged suppression of wool growth. This effect was not mediated by endogenous GH.

Four groups of eight lambs (four male + four female) of about 25 kg live weight were given a concentrate diet which was supplemented with either calcium (Ca) or Ca and phosphorus (P). The levels of Ca and P in the diets were set in relation to estimated requirements (R) as determined by the Technical Committee on Response to Nutrients (TCORN, 1990) and the four treatments were as follows: treatment A Ca and P = 1R; treatment B Ca = 2R P = 1R; treatment C Ca = 4R P = 1R; treatment D Ca = 4R P = 2R.

At about 50 kg live weight the lambs were slaughtered and their body composition was determined.

The composition of their gains was also determined using information obtained from a fifth group of lambs killed at the start of the trial. There were significant treatment effects in relation to body mineral composition with Ca and P levels being higher in lambs on treatments C and D compared with those on treatments A and B. Magnesium levels were also higher in lambs on treatment D. Lambs on treatments A and B grew at the same rate (0·t25 kg/day) and retained Ca and P in relation to live-weight gain at rates close to those on which TCORN (1990) based their estimates of requirements. Lambs on treatments C and D, however, retained these minerals at somewhat higher rates though this improvement in mineralization was accompanied by a slight reduction in growth rate and in some lambs on these treatments there were health problems due to the formation of kidney stones.

The levels of Ca and P recommended by TCORN (1990) for lambs are adequate for normal growth and mineralization. Some improvement in mineralization may be achieved by feeding these minerals at above recommended levels but this improvement would appear to be at the expense of a reduction in growth rate and an increased risk of urolith formation.

Research on the causes of sheep death in sea voyages from Australia to the Middle East is limited, in particular little is known about the influence of climatic factors. Mortality data from 417 shipments of sheep exported over an 11-year period (November 2004 to June 2015) were modelled retrospectively to determine associated climatic factors. The statistical analysis were performed for both the full data set with 417 voyages based on actual and estimated departure and arrival dates and a restricted data set with 71 voyages based on actual dates. The results of the full data set demonstrated a seasonal mortality pattern, with more deaths occurring on sea voyages leaving Australia in the southern hemisphere winter or spring than those departing in Australian summer or autumn. Heat stress and inadequate fat mobilisation for energy supply when sheep are inappetant on shipments may explain this seasonality. Based on these two models, the voyage and weather factors associated with sheep mortalities included departure year, autumn departure in the southern hemisphere, voyage duration, single or multiple loading port(s), weekly mean dry bulb temperature and wind speed at departure ports, and humidity at destination ports. Significant correlations were observed between weather variables at the departure ports in the Australian winter and a high sheep mortality rate during voyages. This, together with the anticipated increased heat stress risk as a result of climate change, suggests that there could be review of the trade from Australia in the southern hemisphere winter. The influence of weather at the departure ports should be considered in sheep mortality prediction models, especially Australia’s heat stress risk assessment model.

Many studies have shown that metabolic efficiency of ruminants can be significantly decreased when B-vitamin supply is insufficient. Under the present state of knowledge, the amounts of B vitamins available for intestinal absorption cannot be predicted based on diet composition. Therefore, in an attempt to increase our understanding of the effects of dietary factors, on B-vitamin supply for dairy cows, the effects of increasing amounts of extruded linseed in diets based on hay (permanent grassland hay, H; Experiment 1) or corn silage (CS; Experiment 2) on apparent ruminal synthesis (ARS) of thiamin, riboflavin, niacin, vitamin B6, folates and vitamin B12 were evaluated. In each experiment, four lactating Holstein cows fitted with cannulas in the rumen and the proximal duodenum were used in a 4 × 4 Latin square design. In both experiments, the dietary treatments consisted of an increasing supply of extruded linseed representing 0%, 5%, 10% or 15% of diet DM. The forage : concentrate ratios were 50 : 50 and 60 : 40 for Experiments 1 and 2, respectively. Duodenal flow was determined using YbCl3 as a marker. The ARS of each B vitamin was calculated as duodenal flow – daily intake. In both experiments, treatments did not affect thiamin, riboflavin, niacin and vitamin B12 duodenal flow or ARS. Increasing the dietary concentration of extruded linseed decreased folate intake in Experiment 1 and vitamin B6 intake in Experiment 2 but resulted in a greater duodenal flow of vitamin B6 and folates regardless of the forage used in basal diet. Greater dietary linseed concentrations decreased vitamin B6 apparent degradation in the rumen in CS-based diet only and increased folate ARS in both H- and CS-based diets. Increasing linseed concentration of isonitrogenous and isoenergetic diets increased vitamin B6 and folate supply to dairy cows, both with H- and CS-based diets.

Despite many recent advances in single nucleotide polymorphism (SNP) genotyping technologies, there is still the need for methodologies with a reasonable throughput. In this study, we compared three PCR-based methods for SNP detection: (1) a conventional PCR-based allele detection system with fluorescent genotyping technology, (2) a SNaPshot methodology by single nucleotide primer extension and, (3) a real-time PCR-based method by allele-specific minor groove-binder probes. These three methodologies were used to analyze 104 meat samples of a particular Italian cattle breed known for producing excellent quality meat and for a characteristic increased development of muscle mass, caused by a point mutation (C313Y) in the Myostatin gene. The analysis revealed 98 samples to be homozygous (mh/mh) and five to be heterozygous (mh/+) for the mutation whereas one sample resulted to be homozygous for the wild type (+/+). The results obtained with the three different assays were consistent. Overall, all three methodologies proved to be efficient for allelic discrimination studies; however, real-time PCR was faster and allowed to genotype up to 96 samples in a single step, minimizing the number of steps required for samples manipulation.

1. Groups of 12 male and 12 female lambs, early weaned and individually fed, were used at six centres in Great Britain to determine the effect of dietary protein concentration on growth rate and feed utilization from weaning to 37 kg live weight. Three diets varying in the proportion of rolled barley to white-fish meal were used to give 13·5, 16·0 or 18·5% crude protein in the dry matter. The diets were pelleted and offered ad libitum.

2. The male lambs showed significantly poorer growth rates and feed conversions on the low-protein than on the other diets. Results for the females were more variable so that although the mean values showed similar trends these were not statistically significant.

3. Female lambs had about 19% lower growth rates than male lambs. The mean food conversion (kg dry matter/kg gain) with the diet containing 16% crude protein was 2·67 for the males and 3·30 for the female lambs. Food utilization differed significantly between centres, the centres using lambs of Finn Dorset breeding having lower growth rates and poorer food utilization than Suffolk crosses.

The hypothesis is proposed that pigs will induce a mechanical stress, by huddling and over-lying, that is related to the degree of thermal stress experienced. Measurements of the floor area covered by groups of 12 pigs have been used to validate the hypothesis.

Forty-eight Greyface wether lambs, aged about 6 months and weighing 32 kg on average were used. They were allocated to be treated, by subcutaneous implantation in the upper surface of the ear flap, with the naturally occurring steroids oestradiol-17β (O), testosterone (T) or the synthetically produced androgen trenbolone acetate (TA). Treatment groups were as follows: sham-implanted controls (C); 50 mg O (slow release formulation) (O); 40 mg TA (compressed pellets} (TA); 50 mg T (compressed pellets) (T); 15 mg O + 40 mg TA (TAO); 15 mg O + 50 mg T (TO). Combined implants were placed in close proximity under the skin of the same ear. The lambs were offered, to appetite, a good quality diet containing per kg dry matter (DM) an estimated 12-0 MJ metabolizable energy and 150 g crude protein. Comparisons were made for the main effects of O and the androgens T and TA. Main effects due to O were increased DM intake, live-weight gain (LWG) empty body weight (EBW), chilled carcass iveight (CCW), carcass crude protein (CP) deposition, plasma insulin concentrations and teat length with reductions recorded for the proportion but not weight of fat in the carcass, plasma urea and thyroxine concentrations. Treatment with androgens did not, on average, influence LWG or other indices of growth performance or carcass composition other than to produce significant increases in carcass phosphorus deposition and reduction in the depth of thorax. Significant increases in the iveight of penile tissue and reductions in teat length were recorded. There was evidence for a greater androgenic effect on penile tissue and anti-oestrogenic effect (on teat length) of TA compared with T at the concentrations used. TA also reduced the weight of the thymus gland, an effect reversed in the presence ofO.

Analysis of plasma taken from the vein contralateral to the site of implantation showed that O concentrations were reduced in the presence of TA and T, and that O had no effect on the concentrations of androgens measured. Concentrations ofT and 17 β-hydroxy-trenbolone in blood were of a similar order, which for T is typical of postpubertal entire male sheep.

The results suggest that O treatment was effective in promoting growth and carcass CP deposition which was not increased by T or TA, despite the presence of these androgens at biologically active concentrations in blood. This effect appears to differ from the additive effects frequently obtained for castrated male cattle.

Research has shown both production and health benefits for the use of chicory (Cichorium intybus) within ruminant diets. Despite this, little was known about the effects of this forage, containing differing fatty acid profiles and secondary plant compounds compared with ryegrass, on beef stability, fatty acid composition or sensory properties. An experiment was conducted to investigate whether the inclusion of chicory in the diet of grazing beef steers would alter these three properties in the M. Longissimus muscle when compared with beef steers grazing perennial ryegrass (Lolium perenne). Triplicate 2 ha plots were established with a chicory (cv. Puna II)/perennial ryegrass mix or a perennial ryegrass control. A core group of 36 Belgian Blue – cross steers were used within a 2-year beef finishing experiment (n=6/replicate plot). In the 2nd grazing year, steers were slaughtered as they reached a target fat class of 3. Muscle pH was checked 2 and 48 h post-slaughter. A section of the hindloin joint containing the M. Longissimus lumborum muscle was removed and a 20 mm-thick steak was cut and muscle samples were taken for analysis of vitamin E and fatty acid analysis. The remaining section of the loin was vacuum packed in modified atmosphere packs and subjected to simulated retail display. A section of the conditioned loin was used for sensory analysis. Data on pH, vitamin E concentration and colour stability in a simulated retail display showed there were no effects of including chicory in the diet of grazing beef steers on meat stability. There were also no differences found in the fatty acid composition or the overall eating quality of the steaks from the two treatments. In conclusion, there were no substantive effects of including chicory in the swards of grazing beef cattle on meat stability, fatty acid composition or sensory properties of the M. Longissimus muscle when compared with beef steers grazing ryegrass-only swards.

Fall-calving multiparous Angus × Hereford cows 3 to 10 years of age were stratified by age in a three by two factorial treatment arrangement to evaluate the efficacy of modifying stocking rate and supplementation strategy to manage cow body condition and production parameters over a 5-year study. Efficacy was evaluated quarterly in association with calving, breeding, weaning, and mid way between weaning and calving (i.e. in August). Three protein supplementation strategies (none, standard, strategic) were imposed across both a moderate (0·3 cows per ha) and a high (0·4 cows per ha) stocking rate. In the strategically supplemented group, protein supplement was provided to cows with a body condition score <5·5 at the quarterly evaluations. There was an effect of supplementation on pregnancy rate, which in combination with previously established culling practices resulted in different age profiles amongst supplementation strategies in years 2 to 5 (P < 0·01). Two statistical analyses were therefore conducted to dissociate the confounding effects of supplementation strategy and age. One model included the effect of stocking rate, supplementation strategy, production year, and all interactions; the second included the addition of age and its interactive effects. Stocking rate and supplementation strategy affected pregnancy rate in each of the models (P = 0·003 and P = 0·10, respectively). Standard, non-supplemented and strategically supplemented animals had estimated pregnancy rates of 0·83, 0·76, and 0·79, respectively (P = 0·10). The effects of nutrition on both calving interval and birth weight were independent of the model employed. Animals that were not supplemented had extended calving intervals (P = 0·06), but there was no effect of stocking rate (P > 0·10). Birth weight was not affected by supplementation strategy or stocking rate (P > 0·10). The lower 205-day weights of calves on a heavy compared with moderate stocking rate was independent of age (P = 0·02). However, the increased 205-day weight of calves born to strategically supplemented cows compared with those born to unsupplemented cows was only evident when data were not corrected for differences in age among groups (P = 0·03). Likewise, analyses of cow condition parameters using models without and with age resulted in different interpretations. These results suggest that strategic and standard supplementation result in similar animal performance and that the improvement in herd productivity associated with altering stocking rate and supplementation may partially be due to altered herd age dynamics.