bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of altering the hay to concentrate ratio and concentrate composition on the rumen fermentation of dry sheep and milk production of lactating dairy ewes
Authors: Zervas G. , Zarkadas L. , Koutsotolis K. , Goulas C. , Mantzios A.
Published: August 2016

In order to examine the effects of diets, with two hay to concentrate ratios and two forms of concentrates on the rumen fermentation of dry sheep and milk production of lactating ewes, three trials were conducted.

In the first trial, four wether sheep, each fitted with a rumen cannula, were used in a 4 × 4 Latin-square design, by allocating them to one of four diets with different hay to concentrate ratio and concentrate type. The diets consisted of 0·5 kg hay and 0·75 kg either starchy (HRSC) or fibrous (HRFC) concentrates, or 0·25 kg hay and 1·0 kg either starchy (LRSC) or fibrous (LRFC) concentrates. The diets were designed to provide similar intakes of energy and crude protein. Volatile fatty acids (VFA) and ammonia concentrations, pH values and number of protozoa were determined in wether rumen fluid.

Total VFA concentration was not significantly affected by diet but acetate and n-butyrate proportions were higher (P < 0·002) on the higher forage diets and propionate higher (P < 0·002) on the lower forage diets. pH values and number of protozoa in sheep rumen fluid were unaffected by treatment, while ammonia concentration was lower (P < 0·05) on the HRFC diet.

In the second trial, 60 lactating dairy ewes were allocated to one of four diets for weeks 11 to 15 of lactation (period 1). Ewes were given food daily: 0·87 kg hay and 1·3 kg either HRFC or HRSC concentrates, or 0·4 kg hay and 1·6 kg either LRFC or LRSC concentrates. During weeks 16 to 20 of lactation (period 2), the ewes were given the same amount and type of concentrates but hay was supplied ad libitum and this period formed the third trial.

Milk yield and milk composition were affected significantly by hay to concentrate ratio with the lower hay to concentrate ratio resulting in a significant increase in milk yield, milk protein efficiency, protein content and protein and lactose yields. Milk fat content and yield were reduced. Hay intake was proportionately greater (P < 0·002) by 0·15 to 0·20 with starchy than with fibrous concentrate diets in period 2. Problems such as acidosis or ‘off-food’ periods in ewes given the low hay to concentrate ratio diets were not observed, irrespective of concentrate type.
Time trends of Gompertz growth parameters in ‘meat-type’ pigs
Authors: Knap P. W.
Published: August 2016

Previously published data from serial slaughter trials on growing pigs of five genotypes were reanalysed. Gompertz curves were fitted to body protein and lipid mass in order to estimate mature protein and lipid mass (P∞,L∞) and the rate parameter (BGompJ that was presumed to be equal for the protein and lipid curves.L∞was expressed as its ratio toP∞, RL∞P∞. The maximum rate of protein deposition was derived as Pdep,max= P∞X BGomp/e. The analysed data encompass body weights of 10 to 133 kg, 13 to 217 kg, 18 to 106 kg, 20 to 110 kg and 11 to 145 kg. The Gompertz function fitted all data sets well, as judged by the standard deviations and distribution patterns of the residual terms. Autocorrelations among the residuals were non-significant.

Averaged over sexes (females and entire and castrated males), the P estimates were all close to 31 kg; the RL∞/P∞estmates ranged from 1·4 to 4·7 kg/kg; the BGompestimates ranged from 0·009 to 0·017 kg/day per kg. The resulting Pdep,max estimates ranged from 110 to 193 g/day. The genotypes were placed in 1969, 1976, 1984, 1990 and 1993. Plotting the estimates against time (year) showed distinct time trends for all parameters except P∞. RL∞/P∞seems to gradually reach a plateau around unity, whereas BGompand Pdep/max increase linearly. These trends were confirmed by an analysis of body weight based on the same data plus data on three other genotypes that spanned the same time period. Analyses of the same protein and lipid data to fit a sigmoid growth function with a flexible point of inflexion did not change the apparently absent time trend of F. The estimates of the inflexion points of the fitted protein accretion curves, expressed as proportions ofF, were indistinguishable from the fixed 0·368 value of the Gompertz function for the earliest three genotypes and then showed a tendency to increase, up to 0·46 for the 1993 population. These time trends must be the consequence of a combination of changes in nutritional and other environmental factors and genetic changes. They cannot be the sole result of within-line selection for growth and body composition traits, since this should increase P∞. It seems as if pig breeders have repeatedly initiated their sire lines from genetic resources with small mature size, to subsequently increase this trait as an indirect result of within-line selection.
Effect of forage to concentrate ratio in the diet on ruminal fermentation and digesta flow kinetics in sheep offered food at a fixed and restricted level of intake
Authors: Carro M. D. , Valdés C. , Ranilla M. J. , González J. S.
Published: August 2016

The effects of four diets differing in their for age: concentrate ratio (80:20, 60:40, 40: 60 and 20:80; g/100 g fresh matter) on rumen characteristics, digestibility and digesta flow kinetics were investigated. Alfalfa hay was used as forage and concentrate was composed of barley, soya-bean meal and maize. Diets were prepared by mixing all ingredients and offered to the animals as complete diets. Eight mature Merino sheep, each fitted with a rumen cannula, were offered 1·055 kg dry matter per day of the corresponding diet over two experimental periods. The daily evolution of ruminai pH, volatile fatty acids (VFA) and ammonia nitrogen (N) concentrations were measured. Digestibility was determined by total faecal collection and Cr and Co were used as markers to estimate digesta passage rates. Microbial nitrogen flow at the duodenum (MNDF) was estimated from the urinary excretion of purine derivatives (PD). The apparent digestibility of organic matter increased (P< 0·001) whereas that of all fibrous fractions decreased linearly (P< 0·05) as the proportion of concentrate in the diet increased. Rumen pH decreased linearly (P< 0·001) with increasing proportions of concentrate but total VFA concentrations were unaffected by changes in the diet (P> 0·05). Both liquid and solid digesta outflow rates from the rumen decreased quadratically (P< 0·01) as the proportion of concentrate in the diet increased. The urinary excretion of total N, urea-N and ammonia-N was unaffected (P> 0·05) by changes in the diet. In contrast, the daily urinary excretion of both allantoin and total PD increased quadratically (P< 0·05) with increasing proportions of concentrate. Consequently, the estimated MNDF increased linearly (P< 0·001) from 9·9 g/day on the high forage diet to 14·5 g/day on the high concentrate diet.
Dynamic selection for maximizing response with constrained inbreeding in schemes with overlapping generations
Authors: Grundy B. , Villanueva B. , Woolliams J. A.
Published: August 2016

A dynamic selection algorithm for maximizing annual genetic response while constraining the rate of inbreeding per generation in populations with overlapping generations is presented. The procedure gives the optimum number of individuals to be selected and the progeny they each produce. The solution to the problem was obtained by using BLUP estimated breeding values, the augmented numerator relationship matrix and lifetime breeding profiles. The procedure was able to constrain the rate of inbreeding per generation to a predefined level across generations of selection by considering all gene flow pathways. The optimization procedure represents an improvement on standard truncation BLUP selection, as it yielded substantially more genetic response (up to 35%) at the same rate of inbreeding.
Relationship between dry matter, fibre and nitrogen degradation characteristics of silage and silage intake of steers
Authors: Dawson L.E.R. , Street R.W.J.
Published: August 2016

A study was carried out to examine the relationship between silage intake and rumen degradability characteristics of silage. The dry matter (DM), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), hemicellulose and nitrogen (N) degradability characteristics of 136 silages were determined using polyester bags in three rumen fistulated beef cross steers. The bags were incubated for 0, 6, 12, 24, 48 and 72 h. Intakes of these silages, by steers, were reported by Steen et al., 1998. The relationships between silage DM intake (g/kg metabolic live weight) and DM, fibre and N degradability characteristics of the silages were poor (R2 < 0·32). Degradability characteristics of the silages were highly negatively correlated with fibre concentration of the silages (R < –0·82) and highly positively correlated with the soluble N minus ammonia concentration (R < 0·77). Some of the degradability characteristics were highly correlated with organic matter digestibility, particularly the proportion of DM, fibre and N degraded after 72 h (R = 0·75 to 0·85). In view of the poor relationship between silage intake and degradability, the results of this study question the rôle of degradation characteristics of DM, fibre and N in the rumen on silage intake.
Association between gene polymorphism of growth hormone and carcass traits in dairy bulls
Authors: Grochowska R. , Lundén A. , Zwierzchowski L. , Snochowski M. , Oprządek J.
Published: August 2016

The contribution of the leucine/valine substitution at amino acid position 127 in the bovine growth hormone (GH) protein to variation in carcass traits was studied. The data included 109 Polish Friesian bulls slaughtered at 15 months of age. The traits measured were carcass gain, weights of meat, bones, intermuscular and subcutaneous fat in the carcass and meat, bones and fat in valuable cuts (fore and best ribs, sirloin, round of beef and shoulder). The bulls’ GH genotype was determined using the PCR-RFLP technique. The frequencies of leucine (Leu) and valine (Val) alleles were 0·64 and 0·36, respectively. The GH concentration was determined in serial blood plasma samples collected every 15 min starting from 15 min before to 135 min after intravenous administration of 0·15 µg thyrotropin releasing hormone (TRH) per kg live weight. Response GH variables were: baseline (the mean of samples collected at –15 and 0 min), peak (the sample taken at 15 min post injection of TRH) and disappearance rate (calculated as peak minus the sample at 60 min, divided by time interval 45 min). Mixed animal models were used for the statistical analysis. Differences were found between the Leu/Leu and the Val/Val genotypes for carcass gain and weight of meat in the carcass (P≤ 0·05). Moreover, differences in the size of the GH peak between the two homozygotes approached significance (P≤ 0·10). The effect of GH genotype accounted for a moderate part of the phenotypic variance in the carcass traits, corresponding to a reduction in the residual variance of ≤ 5·25% when included in the model, whereas the corresponding value for the effect of GH genotype on the variation in GH release was lower, ≤ 1·77%. In conclusion, the Leu/Val polymorphism seems to be associated with carcass traits in dairy bulls, although the effect was relatively small when compared with the effects of season and background genome.
Effects of type and treatment of grain and protein source on dairy cow performance
Authors: Khalili H. , Sairanen A. , Hissa K. , Huhtanen P.
Published: August 2016

The effects of different types of energy or protein supplementation on performance of cows given grass silage-based diets were studied. The possibility of maintaining high energy intakes by using different grain sources, barley or maize, or by the use of the physical processing of the barley was investigated. In addition, the relative quality of rapeseed meal as a protein supplement compared with alternative protein supplements was examined. In experiment 1 16 Finnish Holstein-Friesian cows were used in a cyclic change-over design experiment with eight diets and four 21- day periods. The concentrate supplements comprised a 2 ✕ 2 ✕ 2 factorial arrangement of two grain sources (barley (B) and maize (M)) given either ground (T–) or steam-rolled (T+), each supplemented with either rapeseed expeller (R) or a mixture of maize gluten and soya-bean meal (GS). Grass silage was givenad libitumand concentrates at a rate of 11·2 kg DM per day. M supplements increased milk, milk protein and lactose output (P< 0·05) and decreased milk urea concentration (P< 0·01) compared with B supplements. Blood β-hydroxy-butyrate (BHB) and plasma urea concentrations were higher (P< 0·01) for B than M diets. R supplements increased silage intake, energy-corrected milk yield and milk protein output and concentration (P< 0·05) compared with GS supplements. Steam-rolled grain decreased food intake, blood BHB (P< 0·05) and plasma and milk urea concentrations (P< 0·001). Steam rolling improved organic matter digestibility (grain ✕ processing interaction,P< 0·05) with M but not with B supplements.

In experiment 2 four Finnish Holstein-Friesian cows fitted with rumen cannula were used in a balanced complete change-over design to evaluate ground or steam-rolled barley (T– v. T+) and two protein treatments (rapeseed expeller, R or a mixture of maize gluten/soya-bean meal/sugar beet solubles, GSS). Cows were given concentrates at 11·2 kg dry matter (DM) per day and offered grass silagead libitum. There were no differences (P> 0·05) in food intake, digestibility or milk production and composition between treatments. Plasma urea concentrations (P< 0·01) and molar proportion of butyrate (P< 0·05) in rumen fluid were decreased with R compared with GSS supplements. The results showed that replacing B with M grain resulted in minor increases in milk production. Steam rolling of grain did not influence animal performance. Among the protein supplements R increased animal performance compared with GS supplement.
Genetic parameters of weights, ultrasonic muscle and fat depths, maternal effects and reproductive traits in Welsh Mountain sheep
Authors: Dewi I. Ap , Saatci M. , Ulutas Z.
Published: August 2016

Genetic parameters of weight traits, ultrasonic fat and muscle depths, maternal effects and reproductive traits of Welsh Mountain sheep were estimated based on analyses of data from the nucleus flock of a cooperative breeding scheme. The traits analysed were 12 week weight (TW, no. = 11201), mature weight (MW, no. = 2376), weight at scanning (SW, no. = 1022), muscle depth (SM, no. = 1024), fat depth (SF, no. = 1024), litter weaning weight (LW, no. = 3445) and litter size (LS, no. = 3445). (Co)variance components were estimated in univariate and bivariate animal models. Heritability estimates from univariate analyses were 0.16, 0·49, 0·29, 0·24, 0·22, 0·20 and 0.15 for TW, MW, SW, SF, SM, LW and LS respectively. Genetic correlations among the weight traits were high. There was no detectable correlation between SF and SM. SF and SM were strongly correlated with SW but not with the other weight traits. LW was strongly correlated with MW and SW but not with TW, although the latter analysis was inconclusive. Maternal heritability was similar (0·11) for the univariate analysis of TW and all bivariate analyses involving TW (except for TW v. LW). The permanent environmental effect of dam was generally low (0.02 to 0.04) whilst litter effects were generally high (0·20 to 0·23). The correlation between direct and maternal genetic effects for TW were generally small and non-significant. The maternal genetic effect for TW was moderately correlated with the direct additive effect for MW and SW but was not significantly correlated with the direct additive effect for LS, SM or SF. A very large positive correlation was found between the maternal genetic effect for TW and the direct additive effect for LW. The implications of the results are discussed in the context of selection indices for Welsh Mountain sheep.
Effect of high ambient temperature on protein and lipid deposition and energy utilization in growing pigs
Authors: Bellego L. Le , van Milgen J. , Noblet J.
Published: August 2016

The effects of high ambient temperature (T) on protein (PD) and lipid deposition (LD) and energy utilization were studied on 36 Piétrain ✕ (Landrace ✕ Large White) barrows according to a factorial design including two temperatures (23ºC for thermoneutrality and 30ºC for the high temperature) and four feeding levels. One feeding level corresponded to the voluntary food intake (VFI) at each temperature. Expressed as proportion of VFI at 23ºC, the actual feeding levels were 1·00, 0·90, 0·80, 0·70 at 23ºC and 0·80, 0·73, 0·68 and 0·62 at 30ºC. Animals were offered a wheat, maize and soya-bean meal based diet containing 187 g crude protein per kg and 0·95 g ileal standardized digestible lysine per MJ of net energy. Pigs were housed individually and had free access to water. The experiment started at 24 kg live weight and animals were slaughtered at 65 kg live weight and their body composition was measured. Slaughter of nine control pigs at the beginning of the experiment allowed calculation of the composition of gain (nutrients and energy) according to the comparative slaughter technique. Reduction of metabolizable energy (ME) intake resulted in a reduced live-weight gain at each T: the maximum gain was 1052 g/ day in pigs offered food ad libitum at 23ºC and the minimum (760 g/day) at the lowest intake at 30ºC. Visceral organ mass was lower at 30ºC than at 23ºC but was not affected by feeding level within T. Growth responses were described as polynomial or broken-line functions of ME intake (linear-plateau for PD). Both the slope and the plateau were influenced by T. At 30ºC, PDmax (143 g/day) was reached at 22·8 MJ ME per day, while at 23ºC PDmax (165 g/day) was reached at 28·4 MJ ME per day. In both cases, PDmax was reached at 0·88 of VFI at this temperature. Also the marginal response of PD to ME intake before the breakpoint was affected by T (5·9 and 4·5 g PD per MJ ME at 23ºC and 30ºC, respectively). At identical high ME intake (e.g. 0·80 of VFI at 23ºC), PD was greater at 23ºC than at 30ºC. In contrast, severe food restriction reduced PD at thermoneutrality more than an identical food restriction obtained at high ambient T. The results indicate that heat stress has a direct negative effect on PD and affects the partitioning of energy gain between protein and fat deposition.
Detection of a major gene for litter size in Thoka Cheviot sheep using Bayesian segregation analyses
Authors: Walling G. A. , Bishop S. C. , Pong-Wong R. , Gittus G. , Russel A.J. F. , Rhind S. M.
Published: August 2016

Segregation analyses were applied to data from an experimental sheep flock to investigate the presence of a major gene affecting litter size. The data set contained 14 years of litter size data, with up to five parities per ewe, from Cheviot sheep carrying the putative Thoka fecundity gene from Icelandic sheep. Segregation analyses were performed using a Markov chain Monte Carlo method implemented using Gibbs sampling. Uniform priors were initially used for estimating variance components, the gene effect and fixed effects in the data. Genotypes in the base generation were assumed known based on the use of the imported Icelandic donor semen from the founder rams. The use of alternative priors (naïve and inverse-gamma distributions) for the variance components did not significantly affect the results, demonstrating the data to be sufficiently powerful for the analyses used. Segregation analyses detected a major gene for litter size in the Thoka Cheviot flock increasing litter size by 0·70 lambs per ewe lambing for a single copy of the gene. When the analysis was repeated without fixing the genotypes in the base population, the analyses predicted a different genotype than that previously used for one of the founder rams and suggested the major gene to be segregating in the Cheviot founder animals prior to the introduction of the Thoka rams. A liability threshold analysis was also applied to the data. As identified in other studies, the threshold analysis overestimated the heritability, but the estimated major gene effect was not significantly different from other analyses. The results confirm the segregation of the Thoka gene in a Cheviot flock and highlight the statistical method as a useful tool for identifying carrier animals to be used for future matings.
Effect of tail docking in Awassi lambs on metabolizable energy requirements and chemical composition of carcasses
Authors: Al Jassim R. A. M. , Brown G. , Salman E. D. , Abodabos A.
Published: August 2016

The effect of tail docking on metabolizable energy requirements and carcass characteristics was studied using 80 weaned entire Awassi male lambs. Docking was performed within 3 days of birth and lambs were weaned at 90 days old. Docked and undocked lambs were randomly allocated to four groups, individually penned and offered different amounts of a pelleted concentrate diet. The pelleted diet was estimated to contain 11·8 MJ of metabolizable energy (ME) and 182 g of crude protein (CP) per kg dry matter (DM). Lambs on the high levels of intake were slaughtered at a target weight of approximately 45 kg. Other lambs were maintained on the diet for 149 days before being slaughtered. The right sides of all carcasses were cut into standardized commercial cuts then dissected into muscle, fat and bone. The soft tissue was pooled and analysed for DM, C P, ash and fat. Prediction of live-weight gain (LWG) and empty body gain for a given ME intake (MEI) was made using the growth and MEI data. MEI was expressed as MJ per kg metabolic body weight (M 0·75) per day. Tail docking had no effect (P > 0·05) on lamb growth from birth to weaning. During the post-weaning growth period, LWG and empty body gain were significantly higher (P < 0·05) for undocked lambs than docked lambs, at feeding levels between 0·31 and 0·52 MJ/kg M 0·75 per day and similar (P > 0·05) at high levels of intakes (between 0·74 and 1·1 MJ/ kg M 0·75 per day). Hot and cold carcass weights were similar (P > 0·05) for the two groups. Differences in empty body weight and fleece-free empty body weight were significant (P < 0·05) only for the 0·443 to 0·522 MJ/kg M 0·75 per day level of ME intake. Predicted ME requirements were higher for docked lambs for an estimated LWG between 0 and 100 g/day and lower for higher LWG (125 to 225 g/day). Docking had no effect (P > 0·05) on food conversion efficiency (FCE). Carcasses from docked lambs had significantly lower (P < 0·001) internal plus tail fat. Pooled soft tissue excluding tail fat, for the undocked lambs contained significantly more (P < 0·01) protein, less (P < 0·001) fat, higher (P < 0·01) moisture and similar (P > 0·05) ash content.
The response of growing pigs to amino acids as influenced by environmental temperature. 1. Threonine
Authors: Ferguson N.S. , Arnold G.A. , Lavers G. , Gous R.M.
Published: August 2016

Two similar experiments (1 and 2) were conducted to measure the effects of a range of dietary threonine concentrations and environmental temperatures on the performance of pigs grown from 13 to 25 kg live weight. In both experiments 48 Large White x Landrace entire male pigs were assigned at 13 kg to one of six dietary threonine treatments (8·9 (T1), 7·6 (T2), 6·2 (T3), 4·9 (T4), 3·6 (T5) g/kg and T5 + supplemented threonine (T6)) and one of four temperature treatments (18, 22, 26 and 30°C). Animals were given ad libitum access to food until 25 kg live weight. There were significant interactions (P < 0·05) between temperature and threonine content on the rate of growth (ADG) with the highest gains on T1 and at 22°C. Similarly the response in food intake (FI) to dietary threonine was significantly (P < 0·01) modified by the ambient temperature. An increase in the supply of threonine in the diet resulted in significant increases (P < 0·001) in the gain per unit of food (FCE). A similar response to temperature occurred with the highest FCE recorded at 26°C and the lowest at 18°C. There was a 0·20 proportional reduction in body protein content at 25 kg live weight in pigs given T5 compared with those given T1 and similarly, excluding T6 because threonine may not have been the most limiting amino acid, the fat content was 1·37 higher for pigs on T5 versus T1, which had the lowest fat content. Similar trends occurred in protein and lipid growth rates with maximum protein deposition recorded on T1 (86 (s.e. 3·5) g/day) and maximum lipid deposition on T5 (108 (s.e. 5·8) g/day), over all temperatures. The response in total heat loss was similar to that observed in FI with the effect of decreasing threonine content being dependent on the environmental temperature. Linear regression of daily empty body threonine accretion on daily digestible threonine intake showed an average efficiency of threonine utilization for pigs between 12 kg and 25 kg live weight of 0·59 (s.e. 0·03). There were no differences in efficiency between temperatures. In conclusion, decreasing the threonine concentration below the requirement of the animal ‘resulted in a significant decrease in ADG, reduced FCE and fatter animals. Pigs given a diet deficient in threonine will attempt to maintain threonine intake as the concentration declines by increasing food intake but this compensation is dependent on the environmental temperature. Pigs are able to compensate better for a deficiency in threonine at 18°C and 22°C than at higher temperatures due to the animals being able to dissipate more heat at the lower temperatures.
The changes in body weight and plasma metabolite levels during leptin injection are caused by the reduction of food intake in sheep
Authors: Tokuda T. , Matsui T. , Ito J. , Torii S , Yano H.
Published: August 2016

Leptin is thought to act on the central nervous system as an important regulator of food intake and body weight in mice. To examine the actions of leptin in sheep, we injected recombinant mouse leptin into the lateral cerebral ventricle of ewes. Six ewes were intracerebroventricularly cannulated and given free access to forage and water. The ewes were injected with phosphate-buffered saline (PBS) as a vehicle for 5 days through the cannula and then with PBS + leptin for 7 days consecutively. Although food intake and body weight did not change during PBS injection, the administration of leptin decreased food intake and body weight. Plasma glucose levels decreased and plasma non-esterified fatty acid levels increased on the last few days of leptin administration. Approximately 2 weeks after normal food intake was recovered, the amount of diet was individually reduced in accordance with the recorded food intake during the leptin administration in each sheep. During food restriction, body weight and plasma metabolite concentrations were similarly changed as during the leptin-administration period. These results indicate that leptin decreases food intake in sheep. Moreover, it is likely that the changes in body weight and plasma metabolites were mainly induced by the suppression of food intake during leptin injection.
Birth weight responses to shearing ewes in early to mid gestation
Authors: Morris S.T. , McCutcheon S.N. , Revell D.K.
Published: August 2016

This study compared the effect on foetal growth of shearing ewes in very early pregnancy (day 50) with the effect of shearing later in pregnancy (day 70 or 100). One hundred and sixty ewes were allocated at day 49 of pregnancy to four ‘time of shearing’ treatments — pregnancy day 50 (P50), P70, P100 (no. = 45 ewes per treatment) and unshorn (shearing of this group occurred 43 days after weaning) (no. = 25); two methods of shearing (by standard comb and cover comb); and two levels (1 or 2) of pregnancy/rearing rank. All ewes had been mated over a 28-day period and grazed pasture throughout the trial. The mid point of lambing was 27 August 1996. Live weights of ewes (corrected for fleece weight) were not influenced by shearing time at any stage except at day 45 of lactation when ewes shorn at P50, P70 or P100 were about 3⋅0 kg lighter than unshorn ewes. Shearing method had no effect on ewe live weight. Time of shearing and shearing method had no effect on ewe greasy fleece production or wool tensile strength. Shearing significantly (P < 0⋅05) influenced the birth weight of single- (by 0⋅7 to 0⋅8 kg) but not twin-born lambs. Maternal plasma triiodothyronine concentration increased proportionately by 0⋅47 to 0⋅85 (P < 0⋅05) and lasted for at least 20 days in response to shearing irrespective of time of shearing. No difference in plasma insulin concentration was detected between shearing groups but plasma glucose concentration proportionately increased by 0⋅06 to 0⋅16 (P < 0⋅05) for 10 to 20 days after shearing. These results indicate that shearing between day 50 and 100 of pregnancy can increase lamb birth weights and that the response is associated with an increase in thyroid hormone concentrations in the maternal circulation.
Differences in food resource allocation in a long-term selection experiment for litter size in mice 1. Developmental trends in body weight and food intake against time
Authors: Rauw W. M. , Luiting P. , Verstegen M. W. A. , Vangen O. , Knap P. W.
Published: August 2016

Differences in the metabolic resource situation between non-reproductive male and female mice of a line selected for high litter size at birth (average of 22 born per litter) and a non-selected control line (average of 10 born per litter) were investigated in two replicates. Brody curves were fitted to individual data on body weight against age and linear regression lines were fitted to individual data on cumulative food intake against age. Mature body weight and mature daily food intake were higher in selected mice than in control mice and higher in males than in females. Selected males matured faster than selected females and control mice. In general, differences in growth and food intake curves between species or lines can mostly be explained by differences in mature size. Therefore, parameters were subsequently scaled by individual estimates of mature body weight. Differences that remain after scaling are a consequence of what have been called specific genetic factors. Scaled mature food intake was higher in selected mice than in control mice and higher in females than in males. Scaled maturation rate was higher in selected mice than in control mice and higher in selected males than in selected females. This shows that in the present study, specific genetic factors have been detected for both body weight and food intake, which suggests that selection for increased litter size has disproportionally changed the resource allocation pattern.
Menadione nicotinamide bisulphite as a source of vitamin K and niacin activities for the growing pig
Authors: Marchetti M. , Tassinari M. , Marchetti S.
Published: August 2016

When compared with other menadione derivatives such as menadione sodium bisulphite (MSB), menadione nicotinamide bisulphite (MNB), an organic salt combining menadione and nicotinamide, shows better stability towards physical and chemical factors once it is added to pre-mixes or foods. The present work evaluates the bioavailability of the two vitamins present in this compound and toxicity in the pig. To assess vitamin bioavailability, pigs were given small amounts of food containing MNB or equivalent amounts of MSB and nicotinamide in the free form. Menadione and nicotinamide concentrations in blood samples drawn at set times after the diets were given did not reveal any significant differences between the two modes of administration. Haematic levels of both vitamins in animals receiving MNB, or MSB and nicotinamide, were after 2, 4, 8 and 12 h higher (P< 0·001) than those of untreated animals. The tolerance level to MNB was evaluated in pigs given diets containing graded amounts of MNB (100, 500, 2500 mg/kg) for 28 days. No significant (P> 0·05) differences were recorded in live weight, food intake and gain/food ratio in pigs given these diets when compared with those given an unsupplemented diet. Haemoglobin and bilirubin levels did not differ between animals given various amounts of MNB and control animals. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in pigs given 100 mg/kg of MNB did not show significant differences when compared with those observed in pigs given an unsupplemented control diet. In pigs on the diets supplemented with 500 and 2500 mg/kg of MNB there was a significant increase in the two enzymatic activities as compared with controls (P< 0·001 andP< 0·01). In the case of ALT this had disappeared by 28 weeks. MNB is a good source of vitamin K for the pig and does not appear to have any adverse effects, even when administered at levels higher than those normally used in pig food supplementation.
Prediction of lean meat proportion based on ultrasonic backfat thickness measurements of live pigs
Authors: Hulsegge B. , Merkus G. S. M. , Walstra P.
Published: August 2016

In The Netherlands a system has been developed for classification of live pigs based on lean meat proportion. Ultrasonic backfat thickness measurements were taken on 377 live pigs to assess the ability of the developed system for estimation of the lean meat proportion. The measurements were made at the sites mid point (half the distance from the occipital bone to the base of the tail), mid point –2·5 cm and mid point +2·5 cm, 5 cm off the dorsal mid line.

On the same day, these pigs were slaughtered and the lean meat proportions of the carcasses were estimated using the Hennessy Grading Probe (HGP). HGP measurements were taken between the third and fourth from last rib, 6 cm off the dorsal mid line on carcasses (3/4 LR). The day after slaughter, 88 left carcass sides were randomly chosen to be dissected according to a simplified European Union (EU) reference method.

From the fat thicknesses measured, the one at the site mid point on live pigs was the most accurate predictor for the EU lean meat proportion. The use of multiple site measurements, compared with a single site measurement, significantly reduced the residual standard deviation for the estimation of lean meat proportion.

The site mid point on live pigs differed in longitudinal as well as in dorsal-ventral direction from 3/4 LR on carcasses.

The results of this study suggest that multiple backfat thickness measurements on live pigs can be used for prediction of lean meat proportion with sufficient precision for practical use. Therefore, the developed system can serve as a classification system for live pigs.
Effect of nutrient density and group size on the performance of growing and finishing pigs given food using single-space feeders
Authors: O’Doherty J. V. , McKeon M. P.
Published: August 2016

A 2 ✕ 2 ✕ 3 factorial arrangement of treatments used 522 boars to examine the main effects and interactions of season (spring v. summer), number of pigs per pen with a single-space feeder (13 or 16 pigs per pen with a singlespace feeder; 0·78 m2 per pig v. 0·65 m2 floor space per pig) and nutrient density of the diet (12·5 g lysine per kg and 14·0 MJ digestible energy (DE) per kg from 38 kg to slaughter (high), 12·5 g lysine per kg and 14·0 MJ DE per kg during the growing phase and 10·0 g lysine per kg and 13·6 MJ DE per kg during the finishing phase (split) and 10 g lysine per kg and 13·6 MJ DE per kg from 38 kg to slaughter (low)) on the performance and carcass characteristics of growing and finishing pigs. The smaller group of pigs had a higher food intake during the grower-finisher period than the high stocked pigs (P < 0·01). The pigs had a higher lysine intake in the spring than in the summer months (P < 0·05). Differences in daily food intake for the smaller group of pigs were reflected in increased growth rate during the grower-finisher period (P < 0·001). However these pigs had a poorer food conversion ratio during the grower-finisher period (P < 0·05) than the bigger group of pigs. The pigs offered the high specification and split-fed diets had better growth rate (P < 0·05) than the pigs given the low specification diet during the grower and finisher period. There was a significant two-way interaction in growth rate between dietary treatment and season during the finisher period (P < 0·01). The pigs given the high specification diet had a better growth rate (P < 0·001) than the pigs given the low diets during the summer months. However, the high specification diet depressed growth rate during the spring months (P < 0·05). The pigs had a lower backfat and higher lean meat in the summer than in the spring months (P < 0·05).
Intake and growth of steers offered different allowances of autumn grass and concentrates
Authors: French P. , O’Riordan E. G. , O’Kiely P. , Caffrey P. J. , Moloney A. P.
Published: August 2016

The aim of this experiment was to quantify the relationship between autumn grass supply and concentrate supplementation level on grass intake and animal performance. One hundred and ten continental steers (567 kg) were assigned to 10 treatments. The experimental design was a three grass allowances (6, 12 and 18 kg dry matter (DM) per head daily) by three concentrate levels: (0, 2·5 and 5 kg per head daily) factorial with a positive control group offered concentrates ad libitum and no grass. Grass allowance was offered daily and concentrates were given individually. The experiment began on 22 August and all animals were slaughtered after a mean experimental period of 95 days. Grass intake was calculated using the n-alkane technique and diet digestibility using ytterbium acetate as an indigestible marker. There was an interaction (P < 0·05) between grass allowance and concentrate level for grass intake. At the low grass allowance there was no effect of offering animals supplementary concentrates on grass intake, at the medium and high grass allowances, supplementary concentrates reduced grass intake by 0·43 and 0·81 kg DM respectively per kg DM concentrate offered. Increasing grass allowance increased (P < 0·001) complete diet organic matter (OM) digestibility at all concentrate levels and supplementary concentrates increased (P < 0·001) complete diet OM digestibility only at the low grass allowance. Both offering animals supplementary concentrates (P < 0·001) and increasing daily grass allowance (P < 0·001) increased their carcass growth rate. Relative to the animals offered the low grass allowance and no concentrate, supplementing with concentrate increased carcass growth by 116 g/kg concentrate DM eaten whereas increasing the grass allowance, increased carcass growth by 38 g/kg DM grass eaten. As a strategy for increasing the performance of cattle grazing autumn grass, offering supplementary concentrates offers more scope than altering grass allowance.
Genetic and economic relationships between somatic cell count and clinical mastitis and their use in selection for mastitis resistance in dairy cattle
Authors: Kadarmideen H. N. , Pryce J. E.
Published: August 2016

Clinical mastitis (CM) and monthly test-day somatic cell count (SCC) records on Holstein cows were used to investigate the genetic and economic relationship of lactation average (of natural logarithms of) monthly test-day SCC (LSCC) with CM. After editing, there were 23663 lactation records on 17937 cows from 257 herds. Three groups of herds were first identified as having low (L), medium (M) and high (H) incidences of CM from the original or pooled (P) data set. Genetic parameters were estimated for the original and three data sub-sets (derived from the three herd groups). Expected genetic responses to selection against CM were calculated using genetic parameters of each data set separately, with an adapted version of the UK national index (£PLI-profitable lifetime index). Indirect economic values of SCC (EVSCC) were calculated as the direct cost of CM per cow per lactation weighted by the genetic regression coefficient of CM lactation records on their sires’ predicted transmitting ability for SCC (PTASCC). All genetic regression analyses were based on linear and threshold-liability models. Heritabilities and repeatabilities, respectively, were 0034 and 0·111 for CM and 0120 and 0·347 for LSCC in the original data set. Genetic, permanent environmental, residual and phenotypic correlations between CM and LSCC for the original (pooled) data set were 0·70, 0·44, 013 and 0·20, respectively. Parameter estimates for the three herd groups differed, with magnitude of the estimates increasing with increase in incidence from L to H herd groups. The EVSCCper unit of PTASCCfor L, M, H and P herd groups, respectively, were £004, £0·15, £0·33 and £018 on the observed and £0·86, £0·96, £1·22 and £110 on the underlying-liability scales. Selection for mastitis resistance, using SCC as an indicator trait in an extended version of £PLI, resulted in a selection response of 0·9, 21, 1·7 and 1·9 more cases per 100 cows after 10 years of selection in L, M, H and P herd groups, respectively. These results suggest that genetic responses to selection for CM resistance as well as the EVSCCare specific to herd incidence and hence would be appropriate for customized selection indexes. The increase in CM cases was greater when CM was excluded from the £PLI (2·8v1·9), hence it is recommended that CM should be included in the breeding goal in order to arrest further decline or to make improvement in genetic resistance to clinical mastitis.
Genetic resistance to gastro-intestinal nematode parasites in Galla and Small East African goats in the sub-humid tropics
Authors: Baker R. L. , Audho J. O. , Aduda E. O. , Thorpe W.
Published: August 2016

A study was carried out from 1992 to 1996 to compare the resistance to naturally acquired gastro-intestinal (GI) nematode parasite infections (predominantly Haemonchus contortus) of Galla and Small East African goats in the sub-humid coastal region of Kenya. A total of 204 Galla and 349 Small East African (SEA) kids were born from five kiddings. These were the progeny of 18 Galla and 17 SEA bucks. Live weights (LWT), blood packed-cell volume (PCV) and faecal egg count (FEC) were recorded at 1- to 2-month intervals from birth to about 14 months of age. The SEA kids were more resistant to GI nematode parasites than Galla kids as shown by their significantly lower FEC (P< 0·001) in the post-weaning period (8- to 14-month-old kids) and lower mortality from birth to 14 months of age (P< 0·05). There was no significant (P> 0·05) breed effect on PCV, but Galla kids were significantly heavier (P< 0·001) at all measurement times between birth and 14 months of age. Heritability estimates for LWT, PCV and FEC at the different sampling times were characterized by high standard errors. Heritability estimates for records taken at 4·5 and 8 months of age from a repeated measures analysis were 0·18 (s.e.0·08) for PCV and 0·13 (s.e.0·07) for logarithm-transformed FEC. The phenotypic and genetic correlation estimates between PCV and LFEC were moderately to highly negative and averaged –0·36 and –0·53, respectively. The results are discussed in relation to the limited evidence for resistance to GI nematode infections in goats and compared with the much stronger evidence for resistance in sheep.
The effect of a zinc, cobalt and selenium soluble glass bolus on the trace element status of extensively grazed sheep over winter
Authors: Kendall N. R. , Jackson D. W. , Mackenzie A. M. , Illingworth D. V. , Gill I. M. , Telfer S. B.
Published: August 2016

The effects of trace element deficiencies in lambs, particularly zinc, copper, cobalt and selenium, include decreased growth rates and increased mortality. However, trace element supplementation of sheep reared under extensive conditions has several logistical problems.

Two trials were designed to investigate the effect of a zinc, cobalt and selenium soluble glass bolus on the trace element status of out-wintered ewe lambs. In trial 1 600 8-month-old ewe lambs (500 Scottish Blackface and 100 North Country Cheviots) were allocated to two treatment groups; 300 were treated with a zinc, cobalt and selenium soluble glass bolus (zinc) and 300 were untreated (control). In trial 2, 315 8-month-old Scottish Blackface ewe lambs were allocated to three treatments: 105 were treated with the zinc, cobalt and selenium soluble glass bolus (zinc), 105 were treated with a copper, cobalt and selenium soluble glass bolus (copper) and the remaining 105 were untreated (control). Blood samples were collected immediately prior to giving boluses and again after approximately 4 months. These were assessed for zinc (plasma zinc concentration), cobalt (serum vitamin B12concentration), selenium (erythrocyte glutathione peroxidase activity) and copper status (plasma copper concentration, caeruloplasmin, amine oxidase and superoxide dismutase activity and calculation of the ratio between the caeruloplasmin and plasma copper).

The zinc bolus in both trials significantly increased the plasma zinc concentrations (P< 0·001 andP< 0·01 respectively), erythrocyte glutathione peroxidase activities (P< 0·001) and serum vitamin B12concentrations (P< 0·001). The copper bolus also significantly increased the erythrocyte glutathione peroxidase activities (P< 0·001) and serum vitamin B12concentrations (P< 0·001) when compared with the controls but were not significantly different from the zinc group. The copper bolus significantly increased all of the copper status indicators (P< 0·01) when compared with the control and zinc groups. However, in trial 1 when only the zinc and control groups were compared, the zinc bolus significantly increased the ratio (P< 0·001) and serum caeruloplasmin (P< 0·001) and erythrocyte superoxide dismutase (P< 0·01) activities. These responses were not observed in trial 2 with the erythrocyte superoxide dismutase being significantly reduced in the zinc group when compared with the control group (P< 0·001).

The zinc, cobalt and selenium soluble glass bolus increased the status of all three trace elements consistently for a period of at least 100 days. The increases of cobalt and selenium status were similar to those achieved using the copper, cobalt and selenium bolus, which also increased the copper status of the sheep.
Genetic parameters of milk traits in Latxa dairy sheep
Authors: Legarra A. , Ugarte E.
Published: August 2016

A total of 7444 lactation records which include milk, fat and protein yields (MY, FY, PY) and fat and protein content (F%, P%) from 6429 Black-Faced Latxa ewes were employed to estimate genetic parameters for milk traits. Traits were standardized to 120 days of lactation. For the calculation of composition traits, not all test-days had their composition measured and therefore a correction taking this into account was included in the analysis. A first-derivative restricted maximum likelihood algorithm was used on an animal model with repeatability analysis, using models including fixed effects (flock-year-season of lambing, age-parity at lambing, number of lambs, interval between lambing and first milk recording and the combination of sampled test-days) and random effects (the additive genetic effect and the permanent environmental effect). The resulting heritabilities were 0·20, 0·16, 0·18, 0·14 and 0·38 for MY, FY, PY, F% and P% respectively. Heritability of F% was much lower than expected, probably due to problems derived from the recording method. Genetic correlations were high and positive between yields and moderately positive between F% and P%, and negative or null between yields and composition, as has been reported for other European dairy sheep breeds. As most of the milk produced by Latxa dairy sheep is processed into cheese, the inclusion of milk sampling in official milk recording and a change in the selection criterion are recommended to avoid a long-term worsening in milk composition.