bluuebunny/crossref_metadata_2025_split huggingface dataset:
Continued selection of Romney sheep for resistance or susceptibility to nematode infection: estimates of direct and correlated responses
Authors: Morris C. A. , Vlassoff A. , Bisset S. A. , Baker R. L. , Watson T. G. , West C. J. , Wheeler M. 
Published: August 2016

AbstractDivergent breeding lines of Romney sheep, selected as lambs for consistently high or low faecal worm egg count (FEC) following natural multi-species challenge by nematode parasites, were established in New Zealand at Wallaceville Animal Research Centre in 1979 and at Rotomahana Station in 1985. In 1988 the Rotomahana lines, including an unselected control line maintained under the same management conditions, were transferred to Tokanui Station where they remained for 4 years. In 1993 elite high and low FEC animals from Tokanui, along with the controls, were transferred to Wallaceville, where merged lines have since been managed together. Selection responses from the lines at Rotomahana and Tokanui, and from a further 5 years of divergent selection in the merged lines, are reported here. For the two most recent lamb crops (1996 and 1997 birth years), log-transformed FECs of the high and low lines were 1·27 and -1·46 phenotypic standard deviation units from the control. After back-transformation to the original scale, where the FEC for control line lambs averaged 1255 eggs per g, the means for the high and low lines were 3Ό5 and 0·27 times the control mean. Animal-model restricted maximum likelihood estimates of her it ability and repeatability for single-record FEC (following separate infections) were 0·28 (s.e. 0·02) and 0·42 (s.e. 0Ό1), respectively. Correlated responses in production traits include significantly decreased post-weaning weight gain and increased dags (breech soiling) in lambs, and decreased fleece weight in yearlings and ewes in the low FEC line, compared with those in the high line. However the low FEC line had proportionally 0·11 more lambs weaned per ewe mated than the high FEC line (F < 0·01). It is concluded firstly that selection for high or low FEC in Romney s has achieved an 11-fold difference between the divergent lines. Secondly, it will generally be necessary in a commercial environment to apply index selection for a combination of increased productivity, decreased FEC and possibly decreased dags, when potential candidates are recorded under conditions of nematode challenge.
Animal-intrinsic variation in the partitioning of body protein and lipid in growing pigs
Authors: Knap P. W. , Jørgensen H. 
Published: August 2016

AbstractBody composition in the pig, and its variation, is mostly referred to in terms of body protein and lipid content of the whole body. This study was made to check for animal-intrinsic variation in the partitioning of body protein into protein pools and of body lipid into lipid depots. Results from serial slaughter trials on 316 Danish Landrace and 76 Danish Yorkshire pigs were used to estimate additive genetic and litter-associated variance components for several traits. These traits were total body protein and lipid mass (TOTPROT and TOTLIPD), the proportions of total body protein that are present in the muscles (PROTMUS) or in the (sub-)cutaneous tissue plus bones (connective tissue protein, PROTCON), and the proportions of total body lipid that are present in the (sub-)cutaneous tissue (LIPDSUB), in the muscles (inter- and intramuscular fat, LIPDMUS), or in the bones (LIPDBON). TOTPROT and TOTLIPD were adjusted by regression for body weight; PROTMUS and PROTCON were adjusted for PROTCON, and LIPDSUB, LIPDMUS and LIPDBON were adjusted for TOTLIPD. The pooled estimates (± s.e.) of the degree of genetic determination (the sum of the additive genetic and litter-associated variance components, which approximates the repeatability) of these traits were 0·48 ± 0·19 for TOTPROT, 0·56 ± 0·20 for TOTLIPD, 0·56 ± 0·12 for PROTMUS, 0·57 ± 0·15 for PROTCON, 0·32 ± 0·10 for LIPDMUS, 0·33 ± 0·12 for LIPDSUB, and 0·22 ± 0·10 for LIPDBON. It is concluded that there is animal-intrinsic variation in partitioning of body protein and lipid.
The performance of group-housed sows offered a high fibre diet ad libitum
Authors: Whittaker X. , Edwards S. A. , Spoolder H. A. M. , Corning S. , Lawrence A. B. 
Published: August 2016

AbstractAs a part of a study investigating the extent to which ad libitum feeding of a high fibre diet could mitigate behavioural problems associated with food restriction, the performance of sows given food at restricted or ad libitum levels was compared. Ten subgroups of five were allocated to each of the restricted (R) and ad libitum (A) feeding regimes. Five weeks after service, subgroups were introduced into one of two dynamic groups of sows housed in adjacent straw-bedded pens. R sows received a fixed daily ration (parity 1: 2·2 kg; parity 2: 2·4 kg) of a conventional pregnancy diet (13·1 MJ digestible energy per kg) from an electronic sow feeder. Sows on the A regime had unrestricted access to five single-space hoppers dispensing a high fibre diet (containing 600 g unmolassed sugar beet pulp per kg). Subgroups were maintained on these gestation feeding regimes for two consecutive parities. During both parities, A sows were heavier by day 50 of gestation (parity 1: P < 0·05; parity 2: P < 0·01) and at farrowing (parity 1: P < 0·001; parity 2: P < 0·001) than R sows. No difference was found between feeding regime in sow weight at weaning, due to a greater weight loss during lactation of A (parity 1: P < 0·001; parity 2: P < 0·001) than R sows. No difference was found between feeding regime in sow backfat thickness, sow reproductive performance or litter performance in either parity. This suggests that unmolassed sugar beet pulp diets may be used to feed sows on an ad libitum basis during gestation without compromising productivity. However, food intakes may be too high (estimated at 4·1 kg per sow per day) to make ad libitum feeding of pregnant sows an attractive option for producers.
Lamb production from diverse genotypes. 2. Carcass characteristics
Authors: Fogarty N. M. , Hopkins D. L. , Ven R. van de 
Published: August 2016

AbstractCarcass and meat quality characteristics for 2408 cryptorchid and female lambs at mean carcass weights of 24·8 kg and 19·3 kg respectively are reported. The lambs were sired by a selection of Poll Dorset (D; no. = 7), Texel (T; no. = 10), Border Leicester (BL; no. =12) and Merino (M; no. =12) rams and born to Border Leicester × Merino (BLM) and Merino (M) dams. The lambs comprised six genotypes (D×BLM, T×BLM, D×M, T×M, BL×M and M×M) that represent the range of types (second cross, first cross and Merino) produced in the Australian lamb industry. The second cross (D×BLM, T×BLM) and first cross BL×M were fatter than first cross (D×M, T×M) (1 mm at the GR site) and M×M (3 mm GR) carcasses at the same hot carcass weight (P < 0·01). D cross were leaner than T cross for 24 kg cryptorchid carcasses at the С site (P < 0·01) but there was no difference at the GR site or f or 19 kg female carcasses at either site. There was no difference in M. longissimus thoracis et lumborum (LL) area of first cross and second cross carcasses sired by D and T rams, which were proportionately 0·04 greater than M×M and 0·09 greater than BL×M. The LL area was proportionately 0·04 greater for T than D crosses (P < 0·01). M×M had 0·02 lower dressing yield than other crosses (P < 0·01).There was a significant genotype effect for LL ultimate pH (P < 0·01). BL×M and M×M had higher mean pH and more carcasses than the other genotypes with pH greater than the critical value of 5·8 for meat quality. There were no significant differences between the genotypes for chromameter measures of meat colour. Implications for the production and processing sectors of the lamb industry are discussed.
Declining fertility in dairy cattle: changes in traditional and endocrine parameters of fertility
Authors: Royal M. D. , Darwash A. O. , Flint A. P. F. , Webb R. , Woolliams J. A. , Lamming G. E. 
Published: August 2016

AbstractReproductive performance of 714 Holstein Friesian dairy cows was monitored between October 1995 and June 1998 using thrice weekly milk progesterone determinations. Defined endocrine parameters such as interval topost-partumcommencement of luteal activity, inter-ovulatory interval and length of luteal and inter-luteal intervals were used with a number of traditional measures of reproductive performance to investigate the current status of fertility in a sample of United Kingdom dairy herds. A comparison of the results of the 1995 to 1998 trial with those of a previous (1975 to 1982) milk progesterone database, which included 2503 lactations in British Friesian cows monitored using a similar milk sampling protocol, revealed a decline infertility between these periods.Between 1975-1982 and 1995-1998, pregnancy rate to first service declined from 55·6% to 39·7% (P< 0·001), at a derived average rate approaching 1% per year. This decline was associated with an increase (P< 0·001) in the proportion of animals with one or more atypical ovarian hormone patterns from 32% to 44%. There was a significant (P< 0·001) increase in the incidence of delayed luteolysis during the first cyclepost partum(delayed luteolysis type I; 7·3% to 18·2%) and during subsequent cycles (delayed luteolysis type II; 6·4% to 16·8%), although the incidence of prolonged anovulation post partům (delayed ovulation type I; 10·9% to 12·9%) and prolonged inter-luteal intervals (delayed ovulation type II; 12·9% to 10·6%) did not alter significantly. These changes resulted in an increase in mean luteal phase length from 12·9 (s.e. 0·09) to 14·8 (s.e. 0·17) days and an increase in inter-ovulatory interval from 20·2 (s.e. 0·1) to 22·3 (s.e. 0·2) days. The decline infertility was also reflected in traditional measures of fertility since although interval to first service remained relatively unchanged (74·0 (s.e. 0·4) to 77·6 (s.e. 1·1) days) calving interval lengthened from 370 (s.e. 2·2) to 390 (s.e. 2·5) days. Collectively these changes may have contributed to the decline in pregnancy rates observed over the last 20 years.
Effect of diet energy density and season on voluntary dry-matter and energy intake in male red deer
Authors: Webster J.R. , Corson I.D. , Littlejohn R.P. , Masters B.M. , Suttie J.M. 
Published: August 2016

AbstractFood intake and growth of red deer is lower in winter than in spring and this reduces the efficiency of venison production. Rumen capacity is also lower during winter and this may contribute to the reduced food intake and therefore growth. In the present study, we investigated the ability of deer to regulate food intake during winter and spring by feeding diets of differing energy densities.Six groups of eight male red deer calves were housed indoors in separate pens. Each group was given,ad libitum, a pelleted diet of a different energy density (8·5, 9·0, 9·5, 10·0, 10·5 and 11·0 MJ metabolizable energy (ME) per kg dry matter (DM) for groups 1 to 6 respectively) but the same amount of protein (156 g/kg DM). Food intake of each group was recorded every 2nd day and animals were weighed every 6 days from 17 May to 9 December. For seasonal comparisons, winter was defined as 24 May to 31 August and spring as 1 September to 9 December.There was no difference (P> 0·05) between the mean live weights of the groups at any time during the study. Live-weight gain (LWG) reached a minimum on 4 July and was lower in winter than spring (161 v. 308 g/day, s.e.d. = 10·0,P< 0·001). LWG was positively related (P< 0·001) to diet ME during winter. DM intake (g/kg M0·75per day) and ME intake (MJ ME per kg M0·75per day) decreased until 16 July and increased thereafter. Mean DM intake was lower in winter than spring (83·5 v. 97·2 g/kg M0·75per day, s.e.d. = 2·05,P< 0·001). DM intake increased as diet energy decreased (P< 0·001) in winter and spring with a steeper slope (P< 0·05) in spring than winter. ME intake was not related to diet ME (P> 0·005) and was lower in winter than spring (0·82 v. 0·95 MJ/kg M0·75per day, s.e.d. = 0·25,P< 0·001). Maintenance energy requirement (MEm) across groups and seasons was calculated to be 0·45 (s.e. 0·22) MJ ME per kg M0·75and the energy requirement for LWG (MEf) was 53 (s.e. 8·5) MJ/kg LWG. MEfwas related (P< 0·01) negatively to diet ME during winter.In summary, deer consuming diets with a wide range of energy densities, altered their DM intake, resulting in similar energy intakes and growth rates on all diets. Animals seemed less able to achieve this compensation in winter compared with spring when food intake increased to support the natural rise in growth rate at that time. These results indicate that deer have target growth rates and/or energy intakes that change with season, and are defended by adjusting food intake.
Gene flow and potential selection response in age-structured subpopulations having a common male pool
Authors: Rönnegård L. , Danell Ö. 
Published: August 2016

AbstractIn extensive pastoral systems, where mating cannot be controlled, the breeding strategies of intermingling owner flocks interact. We present a method to evaluate a breeding programme in extensive reindeer (Rangifer tarandus) management which can also be applied to other pastoral production systems. Our main objective was to evaluate the method by applying sensitivity analyses. The method included a gene flow model with maternal effects. The potential responseRpwas defined as the response that could be achieved in a closed nucleus with a given selection procedure. The value ofRpwas derived from the gene flow from dams to daughters, selection differentials, and the realized difference between subpopulations. We studied a population structure having two subpopulations, only one of which had been subjected to selection. Random mating between subpopulations and a common male pool were assumed. A reference case was defined using reindeer data from the literature. After 9 years of continued selection among progeny the estimate ofRpwas 7·0 times higher than the realized subpopulation difference. We analysed deviations ofRpfrom the reference case caused by different female age structures between subpopulations. We also analysed the sensitivity of maternal effects. The method proved insensitive to differences in female age structure between subpopulations but was sensitive to the relative contribution of maternal effects to progeny performance.
Response from marker-assisted selection when various proportions of animals are marker typed: a multiple trait simulation study relevant to the sheepmeat industry
Authors: Marshall K. , Henshall J. , van der Werf H. J. J. 
Published: August 2016

AbstractA simulation study, based on a closed sheepmeat breeding nucleus and incorporating marker-assisted selection (MAS), was used to evaluate response when different proportions of animals were marker typed. Two traits were included in the simulation: trait 1, a production trait where phenotypes were available prior to selection, and trait 2, a carcass trait where phenotypic information was not available on breeding animals. Selection on an index which comprised estimated breeding values (EBVs) for both traits was possible by calculating EBVs for trait 2 as the sum of EBVs for a polygenic component, obtained from a genetic regression, and EBVs for a major gene component, obtained by inferring genotypes at a major gene locus from a linked marker locus. Different marker typing strategies were evaluated. These differed in the criteria used to select progeny for typing, and in the proportion of male and female progeny selected. Typing progeny that were likely to be used as a breeding animal, but excluding those whose marker genotype could be predicted with reasonable certainty, was an efficient genotyping strategy. Close to maximum gain at the major gene locus was achieved when only a proportion of animals were marker typed (for example 90% of maximum response was achieved with a little over one-third of the selection candidates marker typed). This indicates the potential for substantial savings in relation to the cost of marker typing in commercial breeding flocks.
Effect of growth rate on tenderness development and final tenderness of meat from Friesian calves
Authors: Therkildsen M. , Melchior Larsen L. , Bang H. G. , Vestergaard M. 
Published: August 2016

AbstractThe present study was conducted to determine the effect of growth rate of calves on the activity of the calpain system post mortem, post mortem desmin degradation, myofibrillar fragmentation index and meat tenderness of m. longissimus lumborum (LL) and m. supraspinatus (SS). Twenty-four Friesian heifer calves were allocated to two treatment groups: MM and HH. The MM calves were given food to achieve a moderate growth rate (678 g/day from 5 days of age to 90 kg body weight (BW) (period I) and 770 g/day from 90 kg BW to slaughter at 250 kg BW (period II)) and the HH calves were given food to achieve a high growth rate (period I: 895 g/day and period II: 1204 g/day). The myofibril fragmentation index (MFI), desmin degradation and the activity of µ-calpain, m-calpain and calpastatin were measured in LL and SS at slaughter, and 1 and 7 days post mortem. Shear force was measured in LL and SS after 1 and 7 days of ageing and a sensory panel evaluated the eating quality of the loin aged 7 days. MFI (P < 0·01) and tenderness (P < 0·01) were higher and shear force was lower (P < 0·001) in meat from HH calves compared with meat from MM calves. However, growth rate did not affect the activity of µ-calpain, m-calpain or calpastatin or the degradation pattern of desmin at any time post mortem. Besides growth rate and MFI at day 7 post mortem, which both correlated positively with meat tenderness (P < 0·001 and P < 0·01, respectively), fibre type traits and DNA or RNA concentrations were not generally related to final tenderness. Thus, it was concluded that increased growth rate of calves before slaughter increased the ease of fragmentation (MFI) of the meat and improved the tenderness but these findings could not be related to any changes in the activity of the calpain system.
Effect of diet forage to concentrate ratio on rumen degradability and post-ruminal availability of protein from fresh and dried lucerne
Authors: Faría-Mármol J. , González J. , Rodríguez C.A. , Alvir M. R. 
Published: August 2016

AbstractThe ruminal degradation of dry matter (DM) and crude protein (CP) and the intestinal availability of CP of four lucerne samples were measured on two diets with lucerne hay to concentrate ratios of 2: 1 (diet F) and 1: 2 (diet C). Two samples of fresh lucerne (third cut) harvested after 2 (FL1) or 8 (FL2) weeks from the previous cut were used together with a sample of lucerne hay (LH) and another of dehydrated lucerne (DL). Rumen degradability, measured by the nylon bag technique, and rumen outflow rates were determined on three rumen cannulated wethers. Intestinal digestibility was determined by the mobile bag technique on three duodenal fistulated wethers. For CP, significantly lower values were observed with diet C than with diet F for the potentially degradable insoluble fraction (0·334 v. 0·397) and its degradation rate (0·093 v. 0·134 per h). As a consequence, the effective degradability was also lower with diet C (0·746 v. 0·821; P = 0·059). Effective degradability of DM was also apparently lower with diet C (0·596 v. 0·634). With both diets, the intestinal digestibility decreased in all the samples with increase of ruminal incubation time according to a simple exponential equation. The undegraded CP digested in the gut (Di) and therefore the effective intestinal digestibility (EID) were derived from this exponential function according to the rumen outflow of undegraded CP. Mean values of Di (expressed as proportion of food CP content) were respectively 0·091 and 0·142 for F and C diets and 0·084, 0·115, 0·116, and 0·152 for FL1, FL2, LH and DL samples. Lower rumen degradability was partially compensated for by higher Di values resulting in a close correlation between both parameters (r = –0·965; P 0·001). The change of the digestion site associated with the reduction of the effective degradability of CP produced also an increase in the undigested CP as a proportion of food CP. So, these values are respectively 0·087 and 0·112 for F and C diets and 0·053, 0·109, 0·096, and 0·141 for FL1, FL2, LH, and DL samples. No difference in EID between F and C diets was observed (0·529 v. 0·563). For samples, the only effect (P 0·05) was recorded between FL1 (0·618) and the other samples (0·509, 0·544 and 0·512 for FL2, LH, and DL, respectively).
Effect of abomasally infused casein on post-ruminal digestibility of total non-structural carbohydrates and milk yield and composition in dairy cows
Authors: Abramson S. M. , Bruckental I. , Zamwel S. , Arieli A. 
Published: August 2016

AbstractA study was conducted to evaluate the effect of abomasal infusion of casein on post-ruminal digestibility of starch and on milk yield and composition. Six multiparous Israeli Holstein cows in mid lactation, fitted with ruminal and abomasal cannulas, were used in a 3 ✕ 3 Latin-square experiment. Each cow received 1600 g maize starch infused into the abomasum. Treatments were: abomasal infusion of sodium caseinate at 0, 350, or 700 g casein daily. Chromium mordant neutral-detergent fibre (NDF) was used as a digesta marker. Casein infusion was associated with increases in post-ruminal and total-tract digestibility of non-structural carbohydrates and protein. Concentrations of rumen ammonia and of plasma insulin, glucose and urea were higher in casein-infused cows. Concentrations of milk protein and lactose and milk protein yield increased with casein infusion. Results indicate that increased protein flow to the abomasum can improve the yield of milk constituents in dairy cows. Digestibility and yield responses to infusion of 350 g casein per day were similar to those at 700 g/day. There was a tendency toward reduced milk protein efficiency in casein-infused cows. It is suggested that part of the production response can be related to a direct effect of protein supply and the rest can be explained by the indirect effect of improved carbohydrate availability in the small intestine.