bluuebunny/crossref_metadata_2025 huggingface dataset:
The nutritive value of processed roughages for milking cattle
Authors: Campling R. C. , Milne J. A.
Published: September 2010

Processing roughages generally causes marked changes in the particle size of the feed and this review is restricted to the effect of this on nutritive value; processing roughages by chemical methods is not considered. Where possible experiments with milking cows given processed artificially dried forages are discussed, but unfortunately relatively little work has so far been reported with these feeds. It is therefore necessary to refer to results from a much larger body of American information on processing field-cured lucerne, and to the few European studies with milled hays and straws. Much of the work has been done with small numbers of cows and often without reporting the particle size of the processed roughages. On the occasions this information was given it shows that, between experiments, the average particle size of pelleted hay varied enormously from 1·35 mm to 0·22 mm. The average particle size of the feed was the size of mesh through which half the total weight of particles passed (Gill, Campling and Westgarth, 1966). Processing a feed into pellets therefore does not imply a common particle size.
Modern developments in productivity of dairy cows
Authors: Balch C. C.
Published: September 2010

A Productive and efficient dairy industry seems likely to be a valuable national asset for many years to come. At this time of great change in the economic and political forces governing the dairy industry it is more apt to concern ourselves with what will be required of the cow of tomorrow, rather than to indulge in self congratulation on what has already been achieved, great as those advances have been. Analyses of this kind are essential before we can decide what information will be required to meet future conditions; in other words, what research will be necessary.
Maize gluten and rapeseed meal as protein supplements to barley or wheat for intensively finished Charolais-cross bulls
Authors: Pullar D.
Published: September 2010

Four diets, barley/proprietary protein concentrate (B/PC), barley/maize gluten (B/MG), barley/rapeseed meal (B/RSM) and wheat/'rapeseed meal (W/RSM) were formulated to contain 165 g crude protein and 13·0 MJ metabolizable energy per kg dry matter. In experiment 1, all four diets were offered ad libitum to Charolais × Friesian bulls from 187 kg live weight to slaughter at about 488 kg live weight. In experiment 2, the B/PC and B/RSM were offered ad libitum to Charolais × (Hereford × Friesian) bulls from 222 kg live weight to slaughter at about 491 kg live weight. There were no significant differences between treatments in daily live-weight gain, percentage fat and lean in the live animal, slaughter weight or days on experiment in either experiment. In experiment 1, the carcasses from bulls given B/PC were 14 kg heavier than carcasses from bulls given W/RSM (P<0·05), but only 10 and 7 kg heavier than from bulls given B/MG and B/RSM respectively (P<0·05). The killing-out proportion of bulls given B/PC was significantly greater (P<0·05) than bulls given B/RSM. In experiment 2, carcass weights were similar but the killing-out proportion of bulls given B/PC were again greater (P < 0·001). It is concluded that B/MG and B/RSM were as effective as B/PC as finishing diets and that wheat can be successfully substituted for barley, when offered with rapeseed meal.
The eating quality of pork from Meishan and Large White pigs and their reciprocal crosses
Authors: Ellis M. , Lympany C. , Haley C. S. , Brown I. , Warkup C. C.
Published: September 2010

Two studies, one using a trained taste panel and the other a consumer panel, were carried out to evaluate the eating quality of the Meishan breed. Entire male and female pigs of four genotypes: purebred Meishan (MS) and Large Wliite (LW) and the reciprocal crosses (MS♂ × LW ♀ and LW♂ × MS♀) were reared in single sex groups and given a commercial diet ad libitum from 35 kg live weight to slaughter at around 70 kg. For the taste panel, a loin joint was roasted under standard conditions and samples of fat and lean were presented to the panellists. There were no statistically significant differences between the genotypes for tenderness, juiciness, flavour, odour, incidence of boar taint or overall acceptability. Purebred Meishan samples had a higher incidence of abnormal odours but lower cooking losses and shear force values than the other three genotypes. Meat from gilts was judged to be significantly more tender and juicy, with a weaker pork flavour but a lower incidence of abnormal flavours and higher overall acceptability than that from boars. There were statistically significant interactions between genotype and sex for tenderness, abnormal odour and shear force which mainly involved the purebred Meishans and were of little practical significance. In the consumer study, loin chops and leg joints from purebred LW and the two crossbred genotypes were evaluated. Households received two samples of the same type of joint from the same sex in two separate distributions. Each household received an LW sample and a sample from one of the crossbred genotypes. In general, consumers found the appearance of the joints from the three genotypes to be equally acceptable. For eating quality, the within-household deviations of the crossbred compared with the LW suggested that MS♂ × LW♀ samples were considered to be of better eating quality, particularly for juiciness (deviation -0·71, s.e. 0·24, P < 0·01). In contrast, LW♂ × MS♀ samples were generally considered inferior, particularly in terms of juiciness (+ 0·59, s.e. 0·26, P < 0·05) and flavour (+0·63, s.e. 0·27, P < 0·05). However, the overall acceptability of both crossbreds was considered little different from the Large White. Overall, the results of this work suggest little benefit in eating quality for the Meishan under United Kingdom production conditions.
Food ingredient selection by growing and finishing pigs: effects on performance and carcass quality
Authors: Gill B. P. , Onibi G. E. , English P. R.
Published: September 2010

The aim was to investigate if selection of a balanced diet by growing and finishing pigs from foods differing in protein content is modified by the intrinsic nutrient and chemical properties of the high protein food ingredient offered. The treatments were as follows: a free-choice was offered between milled barley and either soya-bean meal (SBM) or low-glucosinolate rapeseed meal (RSM) or an equal mixture of SBM and RSM (SBM+RSM). In two further treatments (SBM/RSM and RSM/SBM) the protein supplements were changed when pigs reached 50 kg. These were compared with a control diet (CONT) formulated to provide 13-0 MJ digestible energy (DE) and 10 g lysine per kg and containing barley (680 g/kg), SBM (150 g/kg) and RSM (150 g/kg). A total of 72 pigs weighing about 30 kg were randomly allocated to the treatments in groups of six (three boars and three gilts). Pigs were slaughtered at about 90 kg and the chilled carcasses were assessed by measuring subcutaneous fat depths and cross-sections of the eye-muscle at the last rib. Responses from 30 to 90 kg on treatments CONT, SBM, RSM and SBM+RSM were, for food intake 2·57, 2·37, 2·21 and 247 (s.e. 0·08) kg/day (P < 0·05), for growth rate 0·93, 0·87, 0·70 and 0·82 (s.e. 0·05) kg/day (P < 0·05) and for food conversion 2·77, 2·72, 3·17 and 3·01 (s.e. 0·181) kg food per kg growth (P > 0·05) respectively. The amount of protein supplement selected in the diet from 30 to 90 kg on treatments SBM, RSM and SBM+RSM averaged 524, 495 and 483 (s.e.d. 64·9) g/kg respectively. With SBM this proportion decreased with increasing body weight (P < 0·01; R2 = 0·58). Changing RSM to SBM at 50 kg increased preference for the protein supplement and intake of SBM averaged 983 g/kg from 50 to 90 kg. On the other hand, switching from SBM to RSM increased preference for barley and intake of RSM averaged 572 g/kg. There were no significant differences in carcass quality but treatments RSM and SBM/RSM tended to produce increased fat depths. In conclusion, the use of RSM did not give a satisfactory level of -performance under the restricted free-choice feeding environment of this study. Preference and nutrient intake were adversely modified by RSM possibly due to the undesirable effects of antinutritive factors.
Population structure of the Sahiwal breed in Pakistan
Authors: Dahlin A. , Khan U. N. , Zafar A. H. , Saleem M. , Chaudhry M. A. , Philipsson J.
Published: September 2010

The present study was undertaken to assist conservation and improvement schemes in the Sahiwal breed of cattle in Pakistan. A data set, consisting of records of 244 pure Sahiwal breeding bulls and 5247 cows, the latter representing about 80% of all recorded Sahiwal cows in Pakistan born during a period covering about 20 years, was analysed with regard to inbreeding, additive relationships, effective population size and generation intervals. Average inbreeding coefficients of 1224 cows and 49 bulls, for which at least the grandparents and great-grandsires were known, were 0·043 and 0·046, respectively. About two-thirds of the inbreeding was due to matings between animals with parents or grandparents in common. The mean additive relationship among the cows was 0·062, with within-herd averages ranging from 0·087 to 0·358. The average population size in a subdata set of recorded Sahiwal cattle from 1980 to 1984 was 1612, whereas the most likely estimate of the effective population size was about 30 animals for the same active breeding population. The study indicated the immediate need for an active conservation programme whereby the Sahiwal subpopulations of India and Kenya also should be involved.
Reproduction management in dairy cattle: a prospective study using progesterone and oestrone sulphate for monitoring pregnancy
Authors: Kourletaki-Belibasaki S. , Stefanakis A. , Vafiadis D. , Hatzidakis G. , Krambovitis E.
Published: September 2010

In a prospective 2-year study, milk progesterone and oestrone sulphate determinations were used to monitor and assess pregnancy in lactating cows. The testing was done centrally at a government regional veterinary establishment which was responsible for providing semen to the farms of the area and also had available specialist expertise in animal reproduction. Sample collection and dissemination of test results were achieved through the network of the artificial insemination service. This approach was preferred because it was considered ergonomic, cost-effective and reliable. Comparison of oestrus behavioural signs and progesterone on the day of insemination revealed that 7·8% (89/1133) of the animals tested had high progesterone levels. Single progesterone testing on day 21 post insemination was not satisfactory for pregnancy diagnosis as the positive predictive value was 83·0% (147/177). The combination of low progesterone on day 0 and high progesterone on day 21 improved the positive predictive value to 87·4% (235/269). Results from 400 samples taken 110 to 130 days post insemination from 53 animals revealed that cows with oestrone sulphate concentrations greater than 0·1 μg/l actually calved. This assay appears to be particularly suitable as a pregnancy confirmation test. A pilot field study implementing a programme of testing on days 0, 21 and 42 for progesterone and between days 110 to 130 for oestrone sulphate not only achieved almost absolute pregnancy predictive values but careful result analysis strongly indicated that the approach of systematic testing can also reveal the fertility profile of a given herd and help to identify potential causes of pregnancy failure from the period of the reproduction cycle in which they occur.
Three-tier open nucleus breeding schemes
Authors: Shepherd R. K.
Published: September 2010

Optimum designs of three-tier open nucleus breeding schemes are evaluated deterministically by maximizing the equilibrium rate of genetic gain for two methods of selection. Methodology is developed for both restricted and unrestricted migration between tiers and incorporates the loss of variance due to selection. A formula is derived for calculating the asymptotic rate of inbreeding. In the extensive livestock industries, proportional improvements in the equilibrium rate of genetic gain of between 0·12 and 0·22 are possible over a closed nucleus if no restrictions are imposed on male and female migration between tiers. The value of the extra tier in an optimized three-tier open nucleus scheme is approximately 0-45 of the maximum proportional improvement of a two-tier open nucleus over a closed nucleus scheme. The optimum structure is to have approximately 1% and 10% of the population in the nucleus and multiplier respectively. With this optimum structure the asymptotic rate of inbreeding will be reduced to one-sixth of that in a closed nucleus. The effects of various factors on the optimum structure, genetic gain and inbreeding are examined. The advantage of a three-tier open nucleus scheme over a closed nucleus scheme can be reduced substantially if thesefactors are operating.
Typology of the evolution of intake by Charolais cows around calving
Authors: Ingrand S. , Agabriel J.
Published: September 2010

Charolais cows were individually given hayad libitumaround calving for two successive winters (no. = 40 and no. = 43). Profiles of hay intake are defined for each cow as the evolution of individual daily intake level around calving.

The aim of this work was to build a typology of these profiles, using multivariate analysis. Four and three groups of cows were distinguished respectively for a 2-month and a 4-month period around calving (PI and PI). These groups corresponded to different kinetics of intake level around calving which were defined as follows: group 1 — plane profiles, with a low difference of intake level between pregnancy and lactation; group 2 — profiles characterized by a marked decrease in intake level just before calving followed by a long and regular increase after calving; group 3 — profiles with no decrease before calving but an early break in the increase in intake after calving; group 4 — intake profiles with a large difference in intake level between pregnancy and lactation. Groups 2 and 3 were pooled for P2.

Cows from groups 2 and 4 increased intake after calving fast enough to prevent the use of their body reserves even with a high milk-production level. Their calculated energy balance became positive very quickly, only 1 week after calving. At the other extreme, a decrease in body reserves was observed for cows which needed at least 1 month after calving to reach their maximum intake capacity and then recover a positive energy balance.
Individual performance and production per unit area of grazing steers of different potential growth rates
Authors: Molinuevo H. A.
Published: September 2010

The purpose of this work was to investigate the relationship between individual animal performance and production per unit area of land of steers of different potential growth rate under different grazing stocking rates (SR). The analysis involved 160 steers divided equally between two breeds, over 2 years at four SRfor each breed and two replicates for each SR. Thus there werefive steers per replicate. The breeds were purebred Aberdeen Angus (Angus) and 4 Limousin (Limousin). After weaning steers were grazed for 251 days on a pasture dominated by Festuca arundinacea. Given that equal SR does not equate to equal treament for breeds characterized to be of different size and rate of growth at a given age, the analysis was undertaken on the basis of three categories of metabolic body size per ha (S). The variables analysed were individual live-weight gain (final minus initial weight, kg), relative individual live-weight gain (logefinal weight - loge initial weight) and production (kg/ha). A mixed model was used to examine effects of breed, S, year and the interactions between these variables. In general significant (P < 0·05) differences were found for all factors of classification and interactions. Independent linear regressions were calculated for each breed between absolute live-weight gain, relative live-weight gain, and production on S. It was concluded that there was a genotype × environment interaction, with the Angus breed tending to show a higher production per unit area than the Limousin, especially at high levels of S when scarcity of forage was apparent. Nevertheless Limousin steers had higher absolute individual performance than the Angus. The higher production of the smaller breed may be explained by a higher SR at a given S level and also by its higher relative individual live-weight gain in relation to that of the larger breed. The data were coded to use Mott's model to study the relationship between absolute performance (kg) and production (kg/ha). However this model ignores the existing interaction involving breeds.
Forages in diets for growing pigs 2. Nutrient apparent digestibilities and partition of nutrient digestion in barley-based diets including red-clover and perennial ryegrass meal
Authors: Andersson C. , Lindberg J. E.
Published: September 2010

Growing pigs fitted with simple t-shaped cannulas posterior to the ileal-caecal valve were used in a change-over design experiment (5 × 5) to determine the Heal and total tract apparent digestibility and hindgut disappearance of dietary components and energy in a barley-based diet with increasing inclusion of either red-clover or perennial ryegrass meal (proportionately 0·10 and 0·20). The total tract and Heal apparent digestibilities of organic matter (OM), crude protein (CP), nitrogen-free extractives (NFE) and energy were significantly reduced with increasing inclusion of red-clover and perennial ryegrass meal in the diet (P < 0·05). For all fibrous components (total fibre (TF), neutral-detergent fibre (NDF), acid-detergent fibre (ADF) and crude fibre (CF)), the ileal apparent digestibility was unaffected by level offibre inclusion in the diet. Also the total tract apparent digestibility of TF, NDF and CF were unaffected by red-clover meal inclusion, while in contrast the total tract apparent digestibility of TF, NDF and CF were significantly reduced with perennial ryegrass meal inclusion (P < 0·05). The hindgut disappearance of crude fat, NDF, ADF and CF was not affected by forage meal inclusion, whereas the hindgut disappearance of OM, NFE, TF and energy were significantly lower in the perennial ryegrass meal diets than in both the control diet and the red-clover meal diets (P < 0·05).

The total tract apparent digestibility of OM was higher for the control diet compared with the red-clover and perennial ryegrass meal diets. There was also a significantly higher apparent digestibility of OM in the total tract for red-clover meal compared with perennial ryegrass meal (P < 0·05). The Heal apparent digestibility of energy in a barley-based diet with forage meal inclusion decreased proportionately by about 0·014, 0·023 and 0·030 units per unit increase ofTF, NDF and CF in dry matter, respectively. Correspondingly, for the total tract energy apparent digestibility, there was a decrease proportionately by about 0·010, 0·016 and 0·022 units per unit increase of TF, NDF and CF in dry matter, respectively. Digestible energy content was significantly reduced, as measured at the ileum or over the total tract, with increasing inclusion offorage meal (P < 0·05).
Mating time and litter size in farm mink selected for confident or timid behaviour
Authors: Malmkvist J. , Houbak B. , Hansen S. W.
Published: September 2010

Farm mink (Mustela vison) have been selected on the basis of their behaviour towards man since 1988 at the Danish Institute of Agricultural Sciences and in this study were offered the possibility to mate 1 week earlier than usual. The objective was to investigate if the behaviour-related selection has affected the reproduction of the farm mink, measured as mating willingness and reproductive success. The animals belonged to three breeding groups: A: selected for curious/confident reactions (17 males, 73 females), B: selected for timid reactions (17 males, 74 females), and C: selected without any demands on reactions towards humans (18 males, 73 females). The time when an average of 50% of the population were mated was 3-6 days for group A; thus the confident were mated 1·7 to 2·1 days earlier than the timid (B) and the control (C) animals. The length of gestation was shorter in group A (46·0 (s.d. 3·0) days) than in group C (47·6 (s.d. 3·6) days) but not different from group B (47·0 (s.d. 3·2) days). Group C had a lower kit mortality from birth to day 50 (11·3%) than groups A and B (20·4 to 21·2%). No significant differences were found between the groups regarding the frequency of successful matings, the ratio of remated females, number of interrupted matings, barren females or litter size. It is concluded that 8 years of selection has led to the development of reproductive differences primarily in the time of mating readiness, whereas the differences seen in kit loss may be related more to random effects.
Effects of pasture grazing or storage feeding and concentrate input between 5·5 and 11 months of age on the performance and carcass composition of bulls and on subsequent growth and carcass composition at 620 kg live weight
Authors: Steen R. W. J. , Kilpatrick D. J.
Published: September 2010

A 3-year experiment has been carried out to compare systems of bull beef production involving pasture grazing and continuous storage feeding and to examine the effects of sward surface height and concentrate input from 5·5 to 11 months of age on grazing behaviour, growth rate and body composition at the end of the treatment period and on subsequent growth rate and carcass composition at commercial slaughter weight. Animals were either set-stocked at pasture to maintain sward surface heights of 6·5 and 10·0 cm or were given grass silage (725 g digestible organic matter per kg dry matter (DM)) supplemented with 0·8, 1·6, 2·4, 3·2 and 4·0 kg cereal-based concentrates (188 g crude protein per kg DM) per head daily. Half of the animals grazed at each sward height were given 1 -6 kg concentrates per head daily while the remainder received no supplement. A total of 255 continental beef breed × Friesian calves which were initially 198 kg live weight were used. From 11 months of age until slaughter at a mean live weight of 620 kg all animals were given grass silage supplemented with 3 kg cereal-based concentrate DM per head daily.

Reducing sward surface height from 10·0 to 6·5 cm increased the proportion of time spent grazing (P < 0·001), reduced the proportion of time involved in other activities and reduced live-weight gain (P < 0·001) from 1·21 to 0·84 kg/day. Offering concentrates at pasture reduced (P < 0·001) the proportion of time spent grazing (the effect being greater with the animals grazing the shorter swards) but did not affect the performance of the animals grazing the taller swards and produced only a modest increase in the live-weight gain (70 g/kg concentrates) of those grazing the shorter swards. At the end of the treatment period, the carcasses of the animals which had been given silage contained proportionally 0·39 more lipid than those of animals which had been at pasture and had the same growth rate. Differences in live weight at 11 months of age due to differences in feeding from 5·5 to 11 months were largely retained until the end of a 7-month period of realimentation while differences in carcass composition at II months were eliminated by slaughter at a constant live weight of 622 kg.
Influence of weaning on carcass quality, fatty acid composition and meat quality in intensive lamb production systems
Authors: Sañudo C. , Sierra I. , Olleta J. L. , Martin L. , Campo M. M. , Santolaria P. , Wood J. D. , Nute G. R.
Published: September 2010

This study investigated the effects of weaning and sex on various aspects of production and quality characteristics in 22 male and 18 female lambs of the Rasa Aragonesa local meat breed. Half the lambs were weaned (W) at 38 to 40 days and half were left unwearied (UW). Both groups were given ad libitum concentrates and cereal straw. Average farm weight was 22·1 kg at 78·3 days. Live-weight gain was significantly different between sexes but not between W and UW lambs. Dressing proportion was higher in UW lambs. Significant differences in fatness were found between W and UW lambs and between sex of lambs. Among the meat quality traits, W lambs had redder and UW lambs paler meat judged by colour a* and haem pigment concentration. No statistical differences were found in the other traits except flavour intensity, which was higher in UW (66·8) than in W (63·6) lambs on a 1 to 100 scale. All other eating quality aspects, in grilled m. longissimus lumborum slices, tended to be higher in UW lambs. The fatty acid composition of subcutaneous and intramuscular fat depots differed significantly (intramuscular fat was more unsaturated and polyunsaturated). There were also differences between W and UW lambs in subcutaneous fat (higher unsaturated in W lambs). However in intramuscular fat composition only differences in polyunsaturated fatty acids (higher in UW lambs), but not in total unsaturated or saturated, were observed. Tatty acids of less than C16 chain length were higher, in both fat depots, in UW lambs than in W lambs reflecting greater incorporation of milk fatty acids. Palatability characteristics were not closely associated with fatty acid composition except that flavour intensity was correlated with total saturated fatty acids.
Estimation of genetic parameters using health, fertility and production data from a management recording system for dairy cattle
Authors: Pryce J. E. , Esslemont R. J. , Thompson R. , Veerkamp R. F. , Kossaibati M. A. , Simm G.
Published: September 2010

The Dairy Information System (DAISY) was developed to record fertility and health information for use in research and to help farmers manage their farms. Data from 33 herds recording health and fertility over a 6-year period were used to study genetic relationships of several health, fertility and production traits. There were 10 569 records from 4642 cows of all parities. These were used to estimate genetic parameters for health: mastitis, lameness and somatic cell score (SCS), for fertility: calving interval, days to first service, conception to first service and for production: 305-day milk, butterfat and protein yields. Heritabilities for these traits were also estimated for the first three lactations. (Co)variances were estimated using linear, multitrait restricted maximum likelihood (REML) with an animal model. Mastitis and lameness were treated as all-or-none traits. The incidence of these diseases increased with lactation number, which may lead to variance component estimation problems, as the mean is linked to the variance in binomial distributions. Therefore, a method was used to fix the within-lactation variance to one in all lactations while maintaining the same mean. The heritability for SCS across lactations was 0·15. Heritabilities for other health and fertility traits were low and ranged between 0·013 and 0·047. All genetic correlations with the production traits were antagonistic implying that selection for yield may have led to a deterioration in health and fertility. The genetic correlation between SCS and mastitis was 0·65 indicating that indirect selection for improvements in mastitis may be achieved using somatic cell counts as a selection criterion. The potential use of linear type scores as predictors of the health traits was investigated by regressing health traits on sire predicted transmitting abilities for type. The results indicate that some type traits may be useful as future selection criteria.
The production parameters influencing the composition and structure of pastoral cattle herds in a semi-arid area of Kenya
Authors: Roderick S. , Stevenson P. , Ndungu J.
Published: September 2010

The size and composition of three herds belonging to Maasai pastoralists were monitored for more than 5 years (1990 to 1996). Animals were categorized as either suckling calves, weaned heifers, weaned males or breeding females. The dates of entries and exits were used to estimate the total number of observed animal days for each category. Fertility rates of breeding females and mortality and disposal rates for each category were estimated using animal days as the denominator. Herd differences were tested using contingency tables. Age to first calving and calving intervals were estimated and examined using analysis of variance tests.

The patterns of births and deaths were seasonally influenced. The mean annual calving rate of all breeding females was 65·6% and for females excluding first calvers was 46·9%. No herd effects were observed. The mean observed interval between calvings was 609 days and the calving interval, calculated from the parturition rate, was 649 days with no herd differences. Mean age at first calving was approximately 4 years with no herd differences. Mean annual mortality rates were 8·9% for breeding cows, 7·8% for weaned males, 6·7% for weaned heifers and 22·1% for calves. The mean annual culling rate of cows was 10·8% and the sale rate of heifers and weaned males was 12·9% and 41·5% respectively. The mean age at disposal of heifers was 655 days and of steers was 801 days. Herd sizes were shown to fluctuate annually with no obvious trend between herds. The main determinants of production identified were the effect of seasonally poor nutrition on the rate of reproduction and the effect of season, herd mobility and disease on mortality.

The study describes production levels that can be used to predict future changes to the system. The results are discussed in terms of the factors influencing and their relevance to pastoral development. The findings are compared with those observed in other, similar areas.
Growth performance, carcass composition and leg weakness in pigs exposed to different levels of physical activity
Authors: Petersen J. S. , Oksbjerg N. , Jørgensen B. , Sørensen M. T.
Published: September 2010

In order to evaluate the effect of exercise training and spontaneous physical activity on growth performance, carcass composition, and locomotory ability 48 female and 48 entire male pigs were subjected to one of three treatments: individual housing in pens of 2-5 m2(confined; C), individual housing and treadmill training for 15 minlday at a speed of 4 km/h, 5 days/week for a period of 70 days (trained; T) and group-housing equal to 0·9 m2per animal (free; F). Pigs in treatment C and T did not differ with regard to daily gain, food intake, kg food per kg gain and carcass lean content. Training did, however, induce significant cardiac hypertrophy (by a proportion of 0·06). In treatment F (i.e. large pens), daily gain was 135 g lower than in treatment C. Dissection of the carcasses showed that treatment F increased the weight of m. psoas major (by 30 g) and the total carcass bone mass (by 130 g) when compared with treatment C. Proportions of carcass lean and intramuscular fat were unaffected by treatment F. Likewise, leg weakness and osteochondrosis did not differ between treatments, whereas the locomotory ability was positively affected by rearing in large pens (treatment F) but not by treadmill training (treatment T). Thus, physical activity in large pens induced various adaptations throughout the body.
Hay for horses: the effects of three different wetting treatments on dust and nutrient content
Authors: Blackman M. , Moore-Colyer M. J. S.
Published: September 2010

Five bales were randomly chosen from a stack of 6-month-old barn-stored hay. Four 2·5-kg sections were taken from each bale and subjected to one of four different water wetting treatments, 0-min soak, 10-min soak, 30-min soak and 80-min steaming. Post wetting, the sections were shaken for 9 min under a Negretti LS45F personal dust sampler which sucked-in any particles released into the surrounding air. The sampler contents were then analysed for respirable particle numbers (particles < 5um), and the hay subsampled and analysed for water-soluable carbohydrate, N, Na, K, Ca, P, Mg, Zn, Mn, Fe and Cu. The steaming and soaking treatments all proportionately reduced respirable particle numbers by more than 0·93 of those present in the dry hay. Soaking for 10 min and 30 min significantly reduced levels of P, K, Mg, Na and Cu, whereas the steamed samples showed no loss of nutrients from the levels present in the dry hay. Thus in terms of reducing respirable particle numbers and conserving nutrient levels, steaming for 80 min is the most effective treatment when preparing hay fodder for horses.
The effects of age at slaughter, genotype and finishing system on the organoleptic properties and texture of bull beef from suckled calves
Authors: Sinclair K. D. , Cuthbertson A. , Rutter A. , Franklin M. F.
Published: September 2010

An experiment was devised to examine the effect of animal age at slaughter, within genotype and finishing system, on bull beef eating quality characteristics to assess the 15 month age limit imposed for bulls at slaughter by the Meat and Livestock Commission specification for improved beef eating quality. The experiment was a factorial design using bulls of two crossbred genotypes (Aberdeen Angus × and Charolais ×), offered two diets (silage-based and barley-based) and slaughtered at two abattoirs. Bulls were slaughtered from approximately 10 months of age on seven dates (ages) at 6-week intervals. Bulls given barley were slaughtered on date numbers 1 to 5 (43 to 67 weeks of age) and bulls given silage on date numbers 2 to 7 (49 to 79 weeks of age). On each slaughter date and at each abattoir the first four commercial steers which followed the bulls on the slaughterline and met the United Kingdom (UK) modal carcass specification R 4L were selected as abattoir, slaughter date and industry representative controls. At 48 h post mortem samples of m. longissimus lumborum; m. biceps femoris; and m. semimembranosus were recovered from all bull and steer carcasses, vacuum packed and stored at 2°C for a fiirther 12 days before freezing and subsequent assessment by a 12 member taste panel and texture analysis using a Warner Bratzler shear jig.

Bulls achieved high growth rates during the finishing period averaging 1·22, 1·55, 1·41 and 1·98 kg/day for silage-fed Angus × bulls; barley-fed Angus × bulls; silage-fed Charolais × bulls; and barley-fed Charolais × bulls, respectively (s.e.d. = 0·08; P < 0·05). Age at slaughter had no significant effect on beef tenderness from young bulls in this study. Similarly, no significant differences in beef tenderness either between genotypes or diets were detected. Bulls, however, produced meat which had lower mechanical shear force values (10·2 v. 11·9 kg for m. biceps femoris; P < 0·001) and was considered to be more tender (P < 0·001), less flavoursome (F < 0·001) and more acceptable (P < 0·01) than that produced by steers.

It was concluded that beef aged for 14 days post mortem and recovered from young bulls which have achieved high growth rates can be at least as good as that representative of the UK standard product. The 15-month age limit for bulls ensures that commercially produced bulls achieve high lifetime growth rates and will produce beef of a quality comparable with that achieved in this study.
Comparative evaluation of beef cattle breeds of African, European and Indian origins. 2. Resistance to cattle ticks and gastrointestinal nematodes
Authors: Frisch J. E. , O'Neill C. J.
Published: September 2010

Cattle breeds of African, European and Indian origins are being evaluated at Rockhampton for their suitability for beef production in northern Australia. In the current study, Belmont Adaptaur (HS), Belmont Red (AX) and Belmont BX (BX) dams were mated to produce straightbreds, and crossbred progeny by Brahman (B), Boron (Bo) and Tuli (Tu) sires. B dams were mated to produce straightbreds, and crossbred progeny by AX, BX, Bo, Charolais (Ch), HS and Tu sires. All animals were reared together in the presence of cattle ticks and gastrointestinal nematodes (‘worms’). Over a 10-month period, half of each genotype was treated every 3 weeks to control ticks and worms. The resistance of each genotype to these parasites was estimated from direct counts of maturing female ticks (‘tick counts’) and from a combination of worm eggs in fresh faeces (‘worm egg counts’) and response to treatment to control the parasites.

The ranking of the sire breeds for tick resistance was B, Bo > BX > AX, HS, Tu > Ch and for worm resistance was B > Bo, BX > AX, Ch, HS, Tu. Only the B × BX and B × Bo could match the resistance of the B to ticks and worms combined.

All genotypes responded to treatment to control parasites but at the low to moderate levels of infestation recorded throughout the study the response of the more resistant genotypes was too low to warrant the cost of treatment. However, the ranking of the genotypes for live-weight gains changed with parasite challenge. Progeny by B and by Bo bulls from each of the dam breeds had higher live-weight gains than the corresponding straightbreds irrespective of the level of parasite challenge but gains of Tu-sired progeny exceeded those of the corresponding straightbreds only at lower levels of parasite challenge. The difference in resistance between the B and the more resistant F2s was small and even at twice the parasite challenge experienced throughout the study, the Fts would still be expected to outgain the B. For those genotypes for which it was measured, heterosis was consistently significant for live-weight gains and for tick counts but not for worm egg counts. Heterosis for live-weight gain was consistently higher for control than for treated groups. Potential roles of the different breeds for crossbreeding is discussed in relation to the effects of different levels of parasite challenge on growth rates of their progeny.
Genetic and phenotypic relationships between food intake, growth, efficiency and body composition of mice post weaning and at maturity
Authors: Archer J. A. , Pitchford W. S. , Hughes T. E. , Parnell P. F.
Published: September 2010

Genetic and phenotypic variation in post-weaning growth, food intake, efficiency and body composition of mice post weaning and at maturity, were examined to determine whether genetic variation in efficiency exists and to predict likely responses to selection for increased food efficiency in post-weaning animals. Genetic variation was found for average daily gain, mid-weight, daily food intake and proportion of body fat both post weaning and at maturity. Residual food intake calculated from phenotypic regression had a heritability of 0·27 (s.e. 0·06) post weaning and 0·24 (s.e. 0·08) at maturity, and was very similar to residual food intake calculated using genetic (co)variances, indicating genetic variation in efficiency exists in post-weaning and mature mice. Although the phenotypic correlation between residual food intake post weaning and at maturity was low (0·29), the genetic correlation was moderate (0·60). This suggests that selection for efficiency in young animals will lead to a correlated improvement in maintenance efficiency of mature animals. Genetic correlation estimates suggest that correlated responses in other traits would include a concomitant decrease in post-weaning food intake, a slight increase in weight at weaning, a slight increase in post-weaning fat proportion and little or no change in post-weaning growth. In mature animals there will be an associated decrease in daily food intake and a slight decrease in mature size and body fat proportion. The results suggest that residual food intake of young animals might be a suitable selection criteria for use in livestock species to improve efficiency in young animals and also in the breeding herd.
Plasma non-esterified fatty acid response to a β-adrenergic challenge before or after feeding in energy underfed or overfed, dry or lactating cows
Authors: Chilliard Y. , Ferlay A. , Desprès L. , Bocquier F.
Published: September 2010

The effects of adrenergic challenge (in order to evaluate the adipose tissue lipolytic potential) and time of challenge relative to feeding on the response curve of plasma non-esterified fatty acids (NEFA) in four underfed or overfed non-lactating non-pregnant cows were studied. Basal NEFA and NEFA response to isoproterenol (ISO; 4 nmol/kg body weight) were higher when challenged before than after feeding and higher in underfed than overfed cows. Interaction between feeding level and time of challenge was significant (P < 0·001) for the rising part of NEFA response. Pooled NEFA response curves from several trials (no. = 63 challenges) were analysed in order to obtain a simplified procedure for the prediction of the NEFA response. High correlations were found between the response area or maximal NEFA response and NEFA response at 15 min (r = 0·95 and 0·98, respectively). This simplified procedure was applied on pooled data from 84 challenges in order to evaluate the effects of energy balance, physiological status, body condition score (BCS) and time of challenge relative to feeding. Energy balance had a significant effect on basal plasma NEFA and NEFA response at 15 min after ISO challenge (–7·6 and –14·2 μmol/l when the daily energy balance increased by 1 MJ, respectively). Time of ISO injection relative to feeding had a greater effect on stimulated NEFA than on basal NEFA (308 v. 239 μmol/l). There was a significant effect of BCS (41 μmol/l per unit of BCS) on the basal plasma NEFA level. The NEFA response at 15 min after ISO challenge was lower (387 μmol/l) in lactating cows than in dry cows. The NEFA response to ISO at 15 min could provide an efficient method of studying the adipose tissue lipolytic potential of cattle in vivo.
A comparison of growth and carcass traits in Scottish Blackface lambs sired by genetically lean or fat rams
Authors: Conington J. , Bishop S. C. , Waterhouse A. , Simm G.
Published: September 2010

An experimental programme was initiated in 1990 to investigate the consequences of selection for reduced fatness in hill sheep and to estimate genetic parameters for carcass traits in the same class of animal. Thirty-two progeny groups of lambs were born as a result of mating Scottish Blackface rams to ewes of the same breed on two Scottish Agricultural College hill farms in 1991 and 1992. Sires were from two divergent selection lines for subcutaneous back fat depth and were selected under ad libitum feeding conditions on an index combining live weight and ultrasonic fat depth at 20 weeks of age. The index was designed to alter body composition but not body weight. Weaned male progeny (reared extensively) were brought together from both farms in August of each year, reared on grass and finished for slaughter on swedes at a target condition score of 3. Measurements taken at weaning were: live weight, average ultrasonic measurements of average subcutaneous fat depth and muscle depth. At slaughter, traits measured were: pre-slaughter live weight, pre-slaughter condition score, age at slaughter, cold carcass weight, killing-out proportion, Meat and Livestock Commission (MLC) fat class and MLC conformation class. Side and shoulder dissections were made on proportionally 0·2 and 0·8 of lambs respectively and lean tissue, subcutaneous fat, intermuscular fat and bone were measured. Comparisons were made between the two genetic lines and genetic parameters were estimated from data adjusted to three different ‘end-points’: constant dissected subcutaneous fat weight, constant age at slaughter and constant cold carcass weight. Moderate to low heritability estimates were obtained for most traits: pre-slaughter live weight = 0·36, cold carcass weight = 0·39, fat class = 0·13, conformation class = 0·09, lean weight = 0·27, bone weight = 0·36 (constant subcutaneous fatness), intermuscular fat = 0·20, subcutaneous fat = 0·20 (constant cold carcass weight). Correlations between ultrasonic measurements at weaning, and slaughter and dissected carcass components were moderate to weak. However, there is sufficient genetic variation in the carcass traits to warrant inclusion in breeding goals for hill sheep. The results also show that genetic differences obtained by selection under intensive rearing conditions for divergent fatness are also seen in progeny reared under extensive (hill) conditions.
Effects of female reproductive rate and mating design on genetic response and inbreeding in closed nucleus dairy herds
Authors: Leitch H. W. , Smith C. , Burnside E. B. , Quinton M.
Published: September 2010

Hierarchical (each dam mated to one sire) and factorial (each dam mated to several sires) designs involving juvenile selection in a closed nucleus breeding programme were compared for rates of genetic response and inbreeding using stochastic simulation. Numbers of sires and dams selected and herd sizes varied. Generations were discrete. Sires and dams were selected at 15 months on the basis of an estimated breeding value (EBV) calculated using selection index which considered information on close relatives. Selection was for total merit index. Matings were carried out assuming use of multiple emulation and embryo transfer (MOET) or in vitro embryo production (1VEP) technologies, over a range of reproductive parameters. Reproductive rates assumed a fixed number of potential offspring per collection with IVEP and MOET. Comparison of mating designs using MOET showed that rates of genetic response and inbreeding with factorial designs voere from 88 to 431% and 36 to 111% of those with the hierarchical design. Generally rates of genetic response were increased and inbreeding decreased by increasing the number of mates per dam due to a reduction of correlations among EBV. Reduced rates of genetic response were occasionally observed in factorial designs involving the mating of dams to large numbers of sires. This increased the generation interval due to the time to carry out the matings. Factorial designs were found to be most efficient for increasing genetic response and or decreasing inbreeding, for breeding programmes involving the selection of equal numbers of sires and dam. For the breeding programmes considered, rates of genetic response with IVEP equalled the best of the MOET designs, achieved at highest MOET rates, at the lowest level of IVEP. But at the equivalent rate of genetic response, rate of inbreeding was increased by 8%. The increased rate of inbreeding was due to the shorter generation interval with IVEP, and the increased probability of selecting related individuals assuming all donors respond to IVEP.
A general method for predicting the weight of water in the empty bodies of pigs
Authors: Emmans G. C. , Kyriazakis I.
Published: September 2010

As water is the major component of the pig body its accurate prediction is of importance in pig growth models. It has become conventional to predict the weight of water, WA kg, from the weight of protein, P kg. The purpose of this paper is to find how this can be done across pig genotypes of different mature size. The widely used equation to relate WA to P is of the form: WA = a.Pb. This equation is examined theoretically. It is concluded that the form of the equation is reasonable and, that while the value of the exponent b is likely to be constant across genotypes, the value of the scalar a is not. It is proposed that the value of the scalar a is best estimated as a = WAPRm Pm1·b where WAPRm is the water: protein ratio in the body at maturity and Pm is the weight of protein in the body at maturity. The value of the parameter WAPRm is assumed to be constant across genotypes with a value in the range of 3·04 to 3·20, depending on the methods used for measuring body composition. The general value of b = 0·855, taken from published work, is confirmed. A consequence of the argument quantified in the paper is that the value of a is predicted to vary from a = 4·69 for a pig with Pm = 20 kg to a = 5·36 for a pig with Pm = 50 kg. The general equation is expected to give more accurate predictions of the weight of water and, hence, of body weight, in models intended to predict pig growth, food intake, body composition and efficiency.