Livestock Science

Editorial Board

2010-08-01

Genetics of adaptation in domestic farm animals: A review

T. Mirkena, G. Duguma, A. Haile, M. Tibbo, A.M. Okeyo, M. Wurzinger, J. Sölkner — 2010-06-07

Abstract: This review summarizes available information on genetics of adaptation in major livestock species focusing on small ruminants. Adaptation to humans and consequences of domestication on predator aversion, mechanisms of adaptation to available feed and water resources, severe climates and genetic evidence of disease tolerance or resistance have been presented. The latter focuses on gastrointestinal parasites and bacterial diseases. The resource allocation by the animal to production and fitness traits under both optimal and sub-optimal conditions has a genetic background. Such information would help in identifying the most appropriate and adapted genotypes capable of coping with the environmental challenges posed by the production systems or, wherever possible, in adapting the environments to the requirements of the animals.

Using copper oxide wire particles or sericea lespedeza to prevent peri-parturient gastrointestinal nematode infection in sheep and goats

J.M. Burke, S. Orlik, J.E. Miller, T.H. Terrill, J.A. Mosjidis — 2010-05-18

Abstract: Gastrointestinal nematodes (GIN) continue to plague the small ruminant industry, especially in parts of the world with warm, humid climates. Alternatives to chemicals are needed for GIN control because of anthelmintic resistance and a desire to reduce chemical residues in meat products. Three experiments using peri-parturient does or ewes addressed the objective: 1) in Arkansas, meat goats were untreated (n=20) or fed copper oxide wire particles (COWP; 2g each) in pelleted sericea lespedeza (Lespedeza cuneata; n=22) before kidding while consuming sericea lespedeza hay, 2) in Arkansas, 42 Katahdin ewes were randomly assigned to remain untreated or were fed COWP (2g each) before lambing within groups fed bermudagrass (Cynodon dactylon) or sericea lespedeza hay in a 2×2 factorial design, 3) in Louisiana, Gulf Coast Native ewes were randomly assigned to remain untreated or were fed COWP (4g each) in a pelleted ration (n=10 each) after lambing began. Fecal egg counts (FEC) and blood packed cell volume (PCV) were determined weekly in all experiments, and coproculture to examine GIN species was conducted in the first two experiments. Haemonchus contortus is typically the predominant GIN in the southeastern U.S., even during cooler months. However, Trichostrongylus spp. was the predominant GIN in Arkansas during these experiments. In all of the experiments, feeding COWP led to a reduction in FEC, but no change in PCV. The sericea lespedeza hay fed to ewes in Experiment 2 was associated with a reduction in FEC compared with ewes fed bermudagrass hay. Kids and lambs from COWP-treated dams in two experiments were lighter than those from untreated dams. Sericea lespedeza aided in the control of GIN infection, and while feeding COWP to peri-parturient ewes and does offered some reduction in GIN infection, body weight of offspring at birth and 60 or 90days of age may be reduced.

Cafeteria trials to determine relative preference of six desert trees and shrubs by sheep and goats

A. Allan Degen, S. El-Meccawi, M. Kam — 2010-05-17

Abstract: Six fodder plants consisting of two leguminous trees, Acacia salicina and Acacia saligna, a leguminous shrub, Cassia sturtii and three halophytic shrubs, Atriplex canescens, Atriplex halimus and Atriplex nummularia were offered ad libitum in cafeteria trials to four fat-tailed Awassi sheep (41.1±3.2kg) and four local Negev goats (36.5±kg). Leguminous plants are characterized by high tannin contents and halophytes by high ash contents. The animals, aged 1.5–2.0years, were randomly picked from a large free-grazing Bedouin flock of sheep and goats that had access to the fodder plants while grazing. They were penned for three weeks prior to measurements during which time they were provided with a maintenance diet. After a 12h fast, the animals were offered the six feeds over a 15min period each day for 5 consecutive days to determine (1) fodder selectivity by these small ruminants and (2) whether the ranking and proportionate feed intakes were similar between sheep and goats. Time-series analyses showed that the intakes and ranking of intakes did not change over the five days. Total DMIs per 15min were similar in sheep (95.6±10.1g) and goats (92.6±17.8g) and feed selection in goats tended to be positively correlated with that of sheep (Mantel test: n=15; r2=0.48; P=0.071). A. saligna was the most preferred feed in both small ruminants (by Jacobs' selectivity index) and the two Acacia species comprised more than 86% and 70% of dietary intakes in goats and sheep, respectively.

Breeding for welfare in outdoor pig production: A simulation study

J.L. Gourdine, K.H. de Greef, L. Rydhmer — 2010-05-26

Abstract: Despite the societal and market attention, to our knowledge, there is no breeding program for outdoor pig production in which improvement in animal welfare is emphasized. In this study, a dam-line selected for an outdoor production system was simulated. The purpose was to investigate the opportunities for improving welfare through traditional selection methods. The genetic gain from simulated breeding programs was compared for three alternative scenarios: 1) a conventional scheme that improves production and reproduction traits (litter size, piglet mortality (PM), mean piglet weight at weaning, weaning-to-mating interval (WMI), average daily gain (ADG) from birth to 20kg, ADG from 20 to 100kg, and lean content); 2) extension of the first scenario with welfare considerations including leg condition of sows after first lactation (LEGw) and additional non-market values on PM and WMI; and 3) a breeding program for welfare in which genetic progress of traits important for welfare (mothering ability and sow longevity) was obtained by increasing the non-market values of LEGw, PM and WMI. The simulation showed that, compared with weights found in the literature, greater weights on LEGw, PM and WMI (approximately 3, 2 and 7 times higher, respectively) were required to avoid deterioration of these traits. The improvement of traits important to welfare was realized with a reduction in the genetic gain of production traits. Thus, the implementation of a breeding program for welfare in outdoor production requires other prerequisites than the market value of the genetic progress only.

Effects of diet protein source on the behavior of piglets after weaning

W.A.G. Araújo, A.S. Ferreira, D. Renaudeau, P.C. Brustolini, B.A.N. Silva — 2010-05-17

Abstract: Forty eight piglets with initial body weight of 5.60±0.75kg, weaned at 21days of age were used to investigate the effects of diet protein source on their behavior and performance after weaning. The piglets were distributed in a completely randomized experimental design, composed of three treatments (a control diet with soybean meal and maize, diet with nonfat dry milk powder and diet with spray-dried plasma), and four replications, with four animals per experimental unit. The piglets' behavior activities were registered and analyzed through the observation of the videos and registered in a work schedule. These images were analyzed continuously, using the “focal” technique. The animals submitted to a control diet demonstrated during the whole period of evaluation a higher incidence of nosing behavior, less time spent at the feeders more time spent with the manifestation of non-desirable agonistic behaviors (P<0.05) than other treatments. The values for feed intake and weight gain, for animals submitted to control diet were lower when compared to animals submitted to plasma and milk powder diet (P<0.05). It is concluded that piglets weaned at 21days of age and fed with simple diets (control diet), based on corn and soybean meal, demonstrate higher incidence of undesirable behaviors and lower growth performance than the piglets that are fed with diets containing spray-dried plasma or nonfat dry milk powder.

Residual feed intake of Angus beef cattle divergently selected for feed conversion ratio

S.N. Smith, M.E. Davis, S.C. Loerch — 2010-05-26

Abstract: A divergent selection experiment using feed:gain ratios as the selection criterion was conducted in the early 1980s using Angus beef cattle located at the Eastern Agricultural Research Station (EARS), Belle Valley, OH. Numbers of bulls completing the 140-d postweaning performance test in 1979 through 1983 were 35, 34, 35, 34, and 33, respectively. Each year, the 3 bulls with the highest feed:gain ratios and the 3 bulls with the lowest feed:gain ratios were selected from the individually fed bulls, and were randomly mated as 2-yr-olds to approximately 20 cows each in a test herd of Angus cows also located at EARS. The progeny of these matings were then fed to assess postweaning and carcass performance. The objective of the current study was to compare the results of the experiment based on divergent selection for feed:gain ratios with those that would have been obtained using residual feed intake (RFI) as the selection criterion. RFI was calculated using 3 approaches: (1) dry matter intake (DMI) adjusted for production (i.e., ADG and metabolic midweight) to derive RFIP; (2) DMI adjusted for ultrasonic backfat thickness at the end of the 140-d test, in addition to ADG and metabolic midweight, to obtain RFIBF; and (3) DMI estimated using the NRC net energy equations, taking into account the energy and feed required for both gain and maintenance, to derive RFINRC. RFI was calculated by subtracting expected feed intake, derived using these 3 approaches, from the observed feed intake. Low RFIP and RFIBF bulls consumed less feed than high RFI bulls, whereas no differences existed for weight traits or ADG. Both feed:gain ratio and RFINRC were significantly correlated with weight traits and ADG on a phenotypic basis. The correlation between RFIP and RFIBF was near 1.0. In addition, rankings of the bulls were very similar based on RFIP and RFIBF. However, RFIBF may be the best selection criterion for feed efficiency examined in this study, as it was phenotypically independent of backfat thickness, in addition to weights and gains, and, therefore, would be less likely to negatively impact marbling score and carcass quality grade.

Comparison of three cooling management systems to reduce heat stress in lactating Holstein cows during hot and dry ambient conditions

2010-05-31

Abstract: The aim of this study was to compare three cooling management systems to improve the physiological status and lactation performance of Holstein cows during summer heat. Multiparous Holstein cows, 32, were blocked according to milk yield divided into four treatments being: C) Control group, cows cooled before milking time (0500 and 1700h daily); AM) cows cooled at 1100h and before milking; PM) cows cooled at 2300h and before milking; and AM+PM) cows cooled at 1100 and 2300h, as well as before milking. Total cooling time per group was 1h for the Control group, 2h for AM and PM groups, and 3h for the AM+PM group. Cows were moved to a holding pen daily to be cooled. Respiration rate (RR) and rectal temperatures (RT) were lowered (P<0.05) by treatment in AM+PM compared to control, but body condition scores were similar among groups. Glucose levels of control cows (48.41mg/dL) were higher (P<0.01) than cooled cows (44.9mg/dL) and AM+PM cows (43.12mg/dL). Other metabolites (i.e., cholesterol, triglycerides) did not differ among treatments, and thyroid hormones (i.e., thyroxin, triiodothyronine) were also similar among the groups. Milk production and milk energy output were higher (P<0.05) in group AM+PM cows (21.12kg of milk and 13.6Mcal per day) than control cows (19.1kg of milk and 12.6Mcal per day), but milk fat and protein proportions were similar among the four groups. Even though cows under the cooling management system with the higher number of coolings per day had better performance, their physiological status does not correspond to a those non-heat stressed lactating cows. Results show that it is necessary to increase the time of cooling to effectively reduce heat stress during severe summer heat conditions.

Effect of vaccination against gonadotrophin-releasing hormone, using Improvac®, on growth performance, body composition, behaviour and acute phase proteins

E. Fàbrega, A. Velarde, J. Cros, M. Gispert, P. Suárez, J. Tibau, J. Soler — 2010-06-08

Abstract: The objective of this study was to evaluate the effect of vaccination against GnRH on performance traits, pig behaviour and acute phase proteins. A total of 120 pigs (36 non-castrated males, NCM; 36 males to be vaccinated, IM; 24 castrated males, CM; and 24 females, FE) were controlled in groups of 12 in pens with feeding stations allowing the recording of individual feed intake. The two vaccinations (Improvac®) were applied at a mean age of 77 and 146days. All pigs were individually weighed every 3weeks from the mean ages of 74 to 176days and backfat thickness (BT) and loin-muscle depth (LD) were also recorded ultrasonically. Twelve group-housed pigs for each treatment were video recorded during 2 consecutive days at weeks 9, 11, 20, 21, 23 and 25 of age to score the number of inactive or active pigs in each treatment group by scan sampling. Aggressive behaviour by the feeder and away from the feeder, and mounting behaviour was also scored by focal sampling. Blood samples from 12 NCM, 12 CM and 12 IM were taken to determine the concentration of circulating acute phase protein Pig-MAP at weeks 1, 2, 4, 11, 13, 21 and 25 of age. After slaughter, the number of skin lesions on the left half carcass was scored. IM presented overall a higher growth rate and daily feed intake compared to NCM (P<0.05), whereas their feed conversion ratios did not differ significantly. In comparison with CM, IM presented a better feed conversion ratio (P<0.05), since their overall daily weight gain did not differ significantly, but IM ate less. Final lean meat percentage of IM and CM was lower compared to that of NCM (P<0.05). Activity, mounting and aggressive behaviour of NCM was higher than in IM, CM and FE after the second vaccination. Pig-MAP concentrations were significantly elevated just after surgical castration and after both administrations of the vaccine (P<0.05), but concentrations subsequently decreased throughout time. Skin lesions of NCM were significantly higher compared to that of IM and FE (P<0.05). The effects of vaccination were especially remarkable after the second dose, when the higher feed intake and lower activity of IM compared to NCM might result in higher final body weight and more fat. Results from this study indicate that some welfare aspects such as a reduced aggression and mounting behaviour may be improved by vaccination against GnRH, together with productive benefits like adequate feed conversion ratio and daily weight gain.

Precipitation of proteins in the rumen fluid using tungstic and trichloracetic acid after feeding sheep thermally treated or untreated soybean meal

Martin Gierus — 2010-06-03

Abstract: The aim of the study was to quantify the protein degradation in the rumen of thermal treated and untreated soybean meal postprandial using trichloracetic (TCA) and tungstic acid (TA) as precipitants of N-compounds in the rumen fluid. The hypothesis is that the difference between TA and TCA precipitation represents peptides with small molecular weight. In two experiments, castrated male sheep were used for the determination of digestibility, N-balance, determination of passage rate of the solid phase, ammonia-N determination in the rumen fluid and for the precipitation trial. The animals were assigned to two treatments in experiments 1 and 2 and fed ad libitum twice a day with chopped wheat straw treated with a solution of 4% NaOH and supplemented with soybean meal either thermally treated (149°C for 4h) (TT) or untreated (UT). Rumen fluid was sampled 0.5, 2.5, 4.5, 6.5 and 7.5h after the morning feeding. The precipitation of N-compounds was affected by a significant interaction among thermal treatment, sampling time and precipitant. At 0.5h postprandial, no differences (P>0.05) in the precipitation for treatment or precipitant were observed. In the TT treatment, TA precipitated significantly more N-compounds in rumen fluid (in mgN/100ml/g of N consumed) at 2.5h onwards. There were no differences (P>0.05) in precipitation of N-compounds in rumen fluid comparing the different postprandial samplings within treatment. Results of ammonia-N determination were in line with those of N precipitation with TA or TCA. At 2.5h postprandial, ammonia-N was significantly higher in UT than TT fed animals. In conclusion, the punctual accumulation of small peptides was not observed through the precipitation of N-compounds in rumen fluid. In general, more small peptides were precipitated when TA was used as precipitant and soybean meal was thermally treated.

Molecular, genealogical and morphometric characterisation of the Pallaresa, a Pyrenean relic cattle breed: Insights for conservation

2010-06-04

Abstract: The Pallaresa cattle breed is a native population of beef cattle found in the western regions of the Catalan Pyrenees (Spain). Since the second half of the twentieth century, population size decreased dramatically in favour of the Bruna dels Pirineus breed. At the present time, it is classified as a relic breed on the brink of extinction by the FAO, as only 22 breeding animals remain alive (2 bulls and 20 cows). Its importance as genetic and cultural heritage and its contribution in maintaining the landscape and ecosystem, as well as its unquestionable interest as a tourist attraction, make it an irreplaceable element in this area.In this paper, we present the breed characterisation of the population at the molecular, genealogical and morphological levels, and the comparison and phylogenetic relationships with other local breeds, in order to contribute to the characterisation of this prominent genetic resource.Genealogical analyses showed that the Pallaresa population is highly inbred. The mean inbreeding for both the whole pedigree and the living population was 18.93% and 25.71%, respectively. A set of 15 microsatellites were typed on the available Pallaresa individuals to ascertain the genetic variability of the breed at the molecular level and to allow a direct comparison with a set of previously studied 19 local cattle breeds from Spain, Portugal and France. The average number of alleles per locus for the Pallaresa breed (4.3) was the lowest of the analysed breeds and the within-population genetic identity, assessed using molecular coancestry, the highest (0.437). The Pallaresa population showed high levels of differentiation from the other analysed breeds. The lowest kinship distance was assessed for the pairs formed with the Bruna dels Pirineus and Salers breeds (0.417±0.010 and 0.427±0.011, respectively). STRUCTURE analysis showed that most Pallaresa individuals were assigned to one distinct cluster, showing that the breed gathers a unique genetic background.Despite its dramatic population scenario, the Pallaresa breed still preserves moderate levels of genetic diversity. The results obtained from the current study can contribute to design appropriate conservation strategies to prevent its extinction in the near future. The implementation of a mating programme involving Pallaresa bulls and Bruna dels Pirineus cows selected according to genetic and morphological closeness to the Pallaresa breed is suggested to prevent the genetic impoverishment of the population.

The influence of the grape pomace on the ruminal parameters of sheep

M.J. Abarghuei, Y. Rouzbehan, D. Alipour — 2010-06-07

Abstract: To overcome an animal feed shortage in Iran, the effect of replacing alfalfa with grape (Vitis vinifera sp.) by-product plus polyethylene glycol (PEG, MW 6000) on the ruminal parameters and retained nitrogen (Nr) of sheep was assessed. In a change-over design experiment 6 sheep with similar live weight (61.8kg), were used during 3 periods of 28days. The three dietary treatments, which were iso-caloric and iso-nitrogenous, were; control (alfalfa hay, barley grain, wheat chaff, wheat straw), GP diet (grape pomace, barley grain, wheat chaff and urea) and GP diet+PEG. PEG was used to deactivate tannins in grape pomace. Animals were held in individual metabolism cages. They were adapted to experimental conditions for 21days, before the commencement of the measurement periods. In each period, the digestibilities of organic matter (OMD), NDF (NDFD), crude protein (CPD) and ruminal parameters (pH, ammonia, bacteria and protozoa population), microbial protein synthesis using urinary purine derivatives and N metabolism in sheep were measured. The concentration of OMD, NDFD and CPD was decreased using grape pomace and the addition of PEG only, improved CPD. The amount of endogenous fecal nitrogen loss and Nr in GP diet were less than control (P<0.05), these amounts were increased by the addition of PEG (P<0.05). GP diet caused reduction in ruminal parameters (pH, ammonia, cellulolytic and proteolytic bacteria population and protozoa number) and microbial protein yield as compared to the control. The addition of PEG increased those parameters (P<0.05). In conclusion, GP diet had a detrimental effect on the rumen parameters and Nr with positive influences of PEG addition on most of these parameters.

Mortality in Austrian dual purpose Fleckvieh calves and heifers

B. Fuerst-Waltl, C. Fuerst — 2010-06-23

Abstract: Most countries worldwide already include functional traits in the breeding goals for cattle. Among those are e.g. reproductive traits or longevity while traits regarding calves or heifers are hardly considered. Mortality, but also culling of heifers before first calving may result in higher replacement costs but also in reduced possibility for selection and is thus of importance in cattle breeding. Thus, the aim of this investigation was to explore the genetic background of postnatal mortality and involuntary culling in Austrian Fleckvieh (dual purpose Simmental) calves and replacement heifers. The following periods were defined for analyses: P1=48h to 30days, P2=31 to 180days, P3=181 to 365days, P4=366days to first calving or a maximum age of 1200days if no calving was reported, P5=birth to age at first calving or a maximum age of 1200days if no calving was reported, P4S=heifers having at least one insemination slaughtered in P4, defined as involuntarily culled. After data editing records of more than 86,000 calves and heifers were investigated. Mortality rates were 1.85, 1.39, 0.36, 0.70, and 5.61% for the defined periods P1–P5, respectively; 7.78% of heifers were involuntarily culled (P4S). For the estimation of genetic parameters a linear and threshold sire model and a linear animal model with the random effects herd⁎year and sire as well as the fixed effects year⁎month, number of dam's parity, and calving ease were applied. In total, the pedigree consisted of 11,609 animals (sire model, sire–dam relationship) and 237,113 animals (animal model). For mortality traits, heritabilities ranged from <0.0001 (P3) to 0.018 (P5) for the linear models, and 0.001 (P3) to 0.072 (P1) for the threshold model, respectively. Heritabilities for involuntary culling (P4S) were 0.024, 0.021 and 0.067 for the linear animal, linear sire and threshold sire model, respectively. The rank correlations were >0.99 between random effects of sires obtained with linear sire and threshold sire models and were lower (r=0.77 to 0.90) for animal and sire models, respectively. Total calf and heifer mortality is higher than stillbirth. Consequently, its economic impact on cattle breeding should not be neglected. Based on the results obtained in this study selection against higher postnatal mortality and involuntary culling of heifers should be possible. Furthermore, monitoring of the population and of extreme bulls might be very useful for breeding organisations to avoid deterioration in these traits.

Performance and meat quality of suckling calves grazing cultivated pasture or free range in mountain

2010-06-14

Abstract: The purpose of this study was to compare the effect of grazing on mountain (M) versus cultivated lowland pasture (C) on the performance and meat quality of suckling calves (Experiments 1 and 2). In addition, the effect of finishing on C after M on growth and meat quality was assessed (Experiment 2). Animals on C and M had on average similar live weight gain and carcass weight in the first experiment. However, the performance depended on year as gain and carcass weight was higher on C than on M in the first year and vice versa in the second year. In the second experiment the calves on M had lower gain and carcass weight than on C. Three weeks finishing on C after M compensated to some extent for the lower growth rate on M. Overall, the results indicate that mountain grazing may yield similar growth rates and slaughter weights as improved lowland pasture depending on year. There were only small effects of pasture type on carcass and meat quality traits like conformation, fatness, intramuscular fat and protein content, and fatty acid (FA) composition. The variation in FA composition could to a large extent be explained by difference in fatness with increase in monounsaturated and decrease in polyunsaturated FA with increasing intramuscular fat content, in turn varying between pasture type, experiment and year. There was a tendency that M led to higher proportion of C18:1n-9 and lower proportion of C18:1n-7 than C, which may be due to difference in milk and forage intake. Both pasture types resulted in meat with intramuscular fat with high nutritional value since the n-6/n-3 ratio was low.

Effect of piglet birth weight on survival and quality of commercial market swine

J.S. Fix, J.P. Cassady, J.W. Holl, W.O. Herring, M.S. Culbertson, M.T. See — 2010-06-14

Abstract: The objective of this study was to determine the effect of individual piglet birth weight on mortality and pig quality in a U.S. commercial production system. Pigs used in this study were farrowed from Large White×Landrace sows (n=463) bred to Duroc boars during a 4week period at a commercial sow farm. Within 24h of birth, all pigs (born alive=5727 and stillborns=513) were weighed and individually indentified. A portion of pigs (16.7%) were cross-fostered to reduce litter size variation during lactation. Individual mortality was recorded daily during the suckling phase. Pigs were weighed 2days prior to weaning (18.7±2.1days of age), finisher placement (74.8±1.9days of age), and 16weeks into finishing (172.8±1.8days of age). During BW collections, an inventory of all live pigs was conducted, and pigs were given a quality score based on visual evaluation of BW and health (3=healthy pig; 2=slightly small and/or slightly unthrifty; 1 small and/or unthrifty). Survival was analyzed for 4 distinct time periods (prenatal, pre-weaning, nursery phase, and finishing phase). Data were analyzed using a logit (survival) or cumulative logit (quality score) function. Birth weight linear effects on prenatal, pre-weaning, and nursery survival as observed mortality probability increased as birth weight decreased. However birth weight did not impact the likelihood of survival during finishing. As birth weight decreased, the likelihood of pigs being poorer quality, quality score (1 or 2), at weaning, finisher placement, and 16weeks into finishing, increased. As birth weight increased the likelihood of a pig being full value at the end of the finishing phase increased. Reduced individual piglet birth weight, was associated with reduced pig quality and likelihood of prenatal, pre-weaning, and nursery survival. Because of the negative impact of birth weight on pre-weaning and nursery survival and pig quality in finishing, as birth weight decreased pigs were less likely to be full value at harvest.

Genetic associations between stayability and reproductive and growth traits in Canchim beef cattle

2010-06-10

Abstract: Stayability is a trait that has a large impact on the costs of rural properties because it is directly related to the cow's ability to produce a certain number of calves over a given period of time. Thus, the objective of this study was to estimate the genetic variance of stayability (STAY) and its genetic associations with age at first calving (AFC), body weight of males and females at 420days of age (BW420), and scrotal circumference at 420days of age (SC420), in order to provide support for a genetic evaluation program on Canchim beef cattle. Genetic parameters were estimated by Bayesian inference using the THRGIBBS2F90 program, considering two-trait analysis between STAY and the other traits. A threshold model was established for STAY and a linear model was established for all other traits. The animal model included the contemporary group as the fixed effect and the genetic additive and residual effects as random effects. The heritability estimates and their respective standard deviations (in parentheses) obtained for STAY, AFC, BW420 and SC420 were 0.03 (0.01), 0.04 (0.01), 0.24 (0.04) and 0.24 (0.06), respectively. STAY presented genetic associations with AFC, BW420 and SC420 of −0.63 (0.20), −0.09 (0.11) and 0.45 (0.21), respectively. It had environmental correlations with AFC and BW420 of 0.02 (0.01) and −0.06 (0.04). For SC420, the environmental covariance was set at zero. Selection for BW420 would not contribute towards improving STAY because the genes that acted on one trait did not act on the other. However, selection to increase SC420 should result in changes in this trait and also favor STAY. Despite the favorable genetic correlation estimates between AFC and STAY, the selection response for both traits would be low. Changes in management and environmental conditions could improve both traits.

Effects of space allocation on growth performance and immune system in weaning pigs

H.K. Oh, H.B. Choi, W.S. Ju, C.S. Chung, Y.Y. Kim — 2010-06-28

Abstract: The objective of this study was to determine the optimum floor space allocation to maximize the immune response and growth performance of weaning pigs. 180 crossbred (6.02±0.55kg) were subjected to a 28-day feeding trial (3 pens/treatment) in which the effects of the following four space allocation were compared: S0.43 (0.43m2/pig; 10 pigs/pen), S0.30 (0.30m2/pig; 14 pigs/pen), S0.27 (0.27m2/pig; 16 pigs/pen) and S0.21 (0.21m2/pig; 20 pigs/pen). Linear effect of space allocation on body weight (BW) at day 14 (P<0.01) and day 28 (P<0.01) after weaning was observed. There was a linear effect of space allocation on average daily gain (ADG) (P<0.05) during the first 14days after weaning. Within 28days of experiment, there was a linear decrease in ADG (P<0.1) with decreasing space allocation. However, no significant linear or quadratic effects were observed in the average daily feed intake (ADFI) or gain: feed ratio (G:F) in response to decreased space allocation during the experiment period. On day 28, the calculated values of the space allocation coefficient, k, were 0.073, 0.052, 0.047, and 0.038 each corresponding to the space allocation of 0.43, 0.30, 0.27, and 0.21m2/pig, respectively. There was a linear increase in the concentration of serum IL-1β and cortisol on day 28 (P<0.05) with decreased space allocation from 0.43 to 0.21m2/pig. The concentration of serum TNF-α was not affected by space allocation. However, the concentration of serum TNF-α was numerically lower in the S0.30 group than in the other groups. Serum IgA and IgG were not influenced by space allocation of the weaning pigs. The linear response to decreasing space allocation from 0.43 to 0.21m2/pig suggests that the space allocation for maximizing growth performance and immune response of weaning pigs until 15kg BW is between 0.30 and 0.43m2/pig. These results indicate that stress caused by reduced space allocation may disrupt the cellular immune system in piglets and stimulate the releases of cortisol.

The effect of pasture allowance and concentrate supplementation type on milk production performance and dry matter intake of autumn-calving dairy cows in early lactation

2010-06-28

Abstract: This study was undertaken to evaluate the influence of daily pasture allowance and concentrate type on milk production performance, dry matter intake, grazing behavior and blood and urinary metabolites of autumn-calving dairy cows in early lactation. The study lasted 61days using 28 Holstein Friesian cows. Prior to experimental treatment, milk production averaged 23.1kg/day (±3.64kg/day) and mean live weight was 595kg (±48.1kg). The four dietary treatments were a combination of two pasture allowances above ground level (low, 25.5 vs. high, 38.5kg of dry matter/cow/day) and two concentrate types offered at the level of 5kg/cow/day (corn-based concentrate vs. sugar beet pulp-based concentrate). Total dry matter intake of individual cows was estimated using the n-alkenes method and milk composition was analyzed weekly using infrared spectroscopy (Foss 4300 Milko-scan). Pasture allowance significantly (P<0.01) increased milk production 22.0kg/day for low and 24.7 for high, respectively. The concentrate energy source had no effect (P>0.05) on milk production, milk fat (3.73%) or protein (3.09%). Pasture dry matter (DM) intake and total DM intake (kg/day) increased from 9.6 to 11.1 and from 13.9 to 15.4 with increased in pasture allowance (P<0.05). Live weight and body condition score were unaffected by either pasture allowance or concentrate type. Plasma NEFA and plasma urea nitrogen (PUN) did not differ with pasture allowance averaging 0.298mmol/l and 8.23mmol/l, respectively (P>0.05). High pasture allowance increased (P<0.05) urinary purine derivatives (allantoin+uric acid/Creatinine (PD/C)) ratio. Concentrate type had no effect on any milk production parameter and the effect of daily pasture allowance was the most significant influencing factor.

Crossbreeding and intensification of smallholder crop–cattle farming systems in Bhutan

T. Samdup, H.M.J. Udo, C.H.A.M. Eilers, M.N.M. Ibrahim, A.J. van der Zijpp — 2010-06-28

Abstract: This paper evaluates the effect of livestock intensification through crossbreeding for dairying in Bhutan, where crossbreeding policies aim to improve smallholder livelihoods. It is also expected that crossbreeding will reduce dairy imports, and will reduce the environmental impact on forests and other common property resources. Since 1985, breeding policies have promoted the Brown Swiss crossbred for high altitude areas and the Jersey crossbred for other areas with suitable agro-ecological conditions. From 1998 onwards, farmers were allowed to choose their desired cattle breed irrespective of the agro-ecological conditions. Data on household, cropping and livestock activities were collected through interviewing 183 households in extensive, semi-intensive, intensive, and intensive peri-urban areas in the years 2000 and 2004. Herd composition on the study farms reflected the policy of promotion of crossbreds in areas with suitable agro-ecological conditions, as well as the preferences of the farmers and their cultural values. The change in livestock breeding policy in 1998 had no apparent impact on the breed composition of the herds. Crossbred cows had 2.4–4.6 times higher milk off-takes than local cows. The livestock gross margins were 1.4–2.4 times higher in the intensive than in the semi-intensive and extensive areas. Crossbreeding has contributed to the higher livestock gross margins in the intensive areas. Cattle management was characterized by high reproductive wastage and poor survival. Crossbreeding has not reduced cattle numbers per farm, but lactating crossbred cows are mainly stall-fed and, so, crossbreeding reduces grazing pressure on common property resources. Crossbreeding has not yet been able to reduce the gap between supply and demand of dairy products in Bhutan. In areas with suitable market conditions, farmers will continue with crossbreeding for dairying, as it is a regular and reliable income source.

Breeding objectives for sheep in Ireland: A bio-economic approach

2010-06-17

Abstract: Breeding objectives for meat sheep in Ireland have been defined and used in the development of selection sub-indices to provide commercial producers with an economic comparison of animals for specific performance trait groups. Using trait-by-trait bio-economic models and a range of methodologies, economic weights (in € per lamb born per genetic standard deviation in the trait) have been calculated for maternal and terminal sire performance traits as follows: production traits; −€1.41 for days to slaughter, €0.35 for carcase conformation class, −€0.52 for carcase fat class, lambing traits; −€0.69 for lambing difficulty for single-bearing ewes, −€0.37 for lambing difficulty for multiple-bearing ewes, €1.15 for lamb survival, maternal traits; €0.83 for number of lambs born, −€1.49 for ewe mature weight, health traits; −€0.09 for lamb foot rot, and −€0.82 for ewe foot rot. Results indicate the significant value of improving the ability of lambs to survive to weaning, without increasing number of lambs born. The highly negative economic weight for both days to slaughter and mature size represents a powerful unfavourable relationship between the two traits.Economic values for lambing difficulty and foot rot represent the significant costs these traits have in the Irish sheep production system.In the early stages of the development of the genetic improvement program for sheep in Ireland the breeding objective defined in this paper provides directed emphasis for trait recording, selection strategies, and mating systems. In addition the economic weights provide indications as to how much genetic improvement in a specific trait would be worth paying for. The proposed formulation of the total economic index as sub-indices provides the ability for commercial farmers to adjust breeding emphasis towards specific market outcomes or address key production aspects in their particular farming system.

Ileal and total tract nutrient digestibility in wheat wet distillers solubles and wheat dried distillers grains with solubles when fed to growing pigs

C. Pedersen, J.E. Lindberg — 2010-06-21

Abstract: The digestibility of dietary components, amino acids and energy in growing pigs fed with wheat wet distillers solubles (WWDS) and wheat dried distillers grains with solubles (WDDGS) was studied in growing pigs fitted with a post valve T-caecum (PVTC) cannula. Eight PVTC cannulated pigs were used in a cross-over arrangement, with four animals per treatment. The coefficients of apparent ileal (CAID) and apparent total tract digestibility (CATTD) of dry matter, organic matter and energy decreased linearly (P<0.05) in diets with increasing dietary inclusion of WWDS and WDDGS. The CAID of crude protein (CP) and fat were unaffected by the dietary inclusion level of WWDS and WDDGS. The CAID of all amino acids were unaffected by increasing dietary inclusion of WWDS and WDDGS. The coefficients of ileal standardized digestibility (CSID) of CP, lysine and histidine were higher (P<0.05) in the WWDS product than in the WDDGS product, while the opposite was found for the CSID of methionine, cysteine, isoleucine, leucine and valine. The CSID of CP and phenylalanine in WWDS and WDDGS, and of lysine in WWDS were at the same level as those reported for wheat bran. However, the CSID of CP and essential amino acids were lower in WWDS and WDDGS than in wheat, wheat flour and wheat middlings. The digestibility values presented make it possible to formulate diets for pigs with inclusion of WWDS and WDDGS with better precision, in particular with respect to the supply of essential amino acids.

Feed conversion rate and estimated energy balance of free grazing Iberian pigs

2010-06-28

Abstract: A direct in situ observation method has been used, observing ingestive bites taken by continuously monitored Iberian pigs (10 uninterrupted hours, from 08:30 to 18:30) to calculate intake of acorns and grass and grazing activity during the fattening period in the dehesa (cleared Mediterranean forest like savannah) from November first to the end of December. The obtained results, together with measurements of weight gain, have been used to propose a new method for calculating stocking rate capacity. 60 grazing days have been studied corresponding to different randomly chosen Iberian pigs (110.2±1.3kg of average initial LW) during 2months. The results show a daily intake of 56.4±2.34MJ ME from grass and acorns, of which acorns accounted for 90.42% (2.92±0.13kg of kernel DM and 0.49±0.04kg of grass DM); to do so pigs walk 3.9±0.18km in 369.0±7.8min of activity which happens at an average temperature of 7.6±0.2°C. The daily expenditure of ingested energy is divided as follows: 13.8±0.18MJ for the resting metabolism (54.1%±0.44); 5.5±0.14MJ for thermoregulation (21.5%±0.29); 6.3±0.15MJ for grazing, divided in displacement (8.0%±0.32) and standing (16.4%±0.25) during the activity. The total energy cost is therefore 25.7±0.38MJ ME, which equals 51.2%±2.71 of the ingested ME. ME available for production was 30.7±2.33MJ per pig and day, equivalent to 0.8±0.06MJ/kg LW0.75 per day. The total heat losses were 31.8±0.59MJ per pig and day. The corresponding ratios are: 253.0±13.05g/kg DM for gain/feed, 15.3±0.79g/MJ for gain/ME intake and 1.4±0.06MJ/kg LW0.75. There are not significant differences between both sexes.With an average daily weight gain of 0.79±0.03kg, the conversion rate of the ME consumed as grass and acorns is 56.4±2.34MJ ME (corresponding to 4.0±0.29 Kg kernel DM and 0.7±0.08kg of grass DM). To ingest that amount of energy pigs have to use 10.5±0.75kg of entire acorns to shell these. Bearing in mind that the annual production of acorns of an average adult evergreen oak (Q. ilex rotundifolia) acorn production is very close to this amount, it could be established that pig feed conversion rate (FCR) for acorn equals the total acorn production from one adult tree. So stocking rate may be estimated by dividing the number of adult oaks of a dehesa by the expected weight gain; and it could be established that stocking rate should be <1pig/ha of dehesa to gain the minimum standard of 46kg only grazing natural resources.

De novo fatty acid synthesis and balance of fatty acids of pigs fed different fat sources

P. Duran-Montgé, C.E. Realini, A.C. Barroeta, R.G. Lizardo, E. Esteve-Garcia — 2010-06-28

Abstract: Dietary fatty acid composition has been shown to influence fat deposition in rodents, chickens and pigs. Results in pigs, however, have been less clear than in other species and may relate to the level of fat/oil added to the diet and the reporting of gross carcass composition instead of gravimetrically measured fat content. The objectives of the experiment were to study the effect of dietary fat composition on whole pig (carcass+viscera) fatty acid (FA) composition and to perform a whole-body balance in order to study de novo FA synthesis and the fate of essential FA.Seventy crossbred gilts (61.8±5.2kg BW) were divided into 10 animals per treatment. Pigs were fed one of seven treatments: a semi-synthetic diet formulated to contain a very low level of fat (NF) and six fat supplemented diets (10%) based on a barley–soybean meal. The supplemental fats were tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), blend (FB) (55% tallow, 35% sunflower oil, and 10% linseed oil) and fish oil blend (FO) (40% fish oil and 60% linseed oil). In addition, 5 pigs were killed at 61.8kg to measure body composition at the start of the balance period. Carcass and viscera fat content and FA composition were determined to perform a balance in pigs growing from 61.8 to approximately 100kg BW. Whole-body FA composition reflected dietary treatments; viscera showed a high content of long-chain polyunsaturated fatty acids. Whole-body fat content of HOSF (26.7%) and SFO (26.7%) fed animals was higher than T (22.9%) fed animals (P<0.05). The ratio of de novo FA synthesis (endogenous FA) of pigs fed the very low fat diet was 1.6:1.0:3.0 for palmitic, stearic and oleic acids, respectively. The different diets containing high amounts of polyunsaturated FA (SFO, LO and FO) showed deposition ratios (not catabolizated exogenous FA) of linoleic and linolenic acids between 64.8 and 66.5, and 62.9 and 64.1%, respectively, whereas deposition rates of arachidonic, eicosapentaenoic and docosahexaenoic acids were 33.6, 47.9 and 48.9%, respectively. Tissue content of eicosapentaenoic acid and arachidonic acid increased in the diets containing high levels of linolenic and linoleic acids (P<0.05), respectively, but the diet containing high linolenic acid did not increase docosahexaenoic acid deposition (P<0.05). In conclusion, dietary tallow lowers whole animal fat content as compared to sunflower oil and high-oleic sunflower oil diets.

Body reserve mobilization during lactation in first parity sows and its effect on second litter size

A.C. Schenkel, M.L. Bernardi, F.P. Bortolozzo, Ivo Wentz — 2010-06-29

Abstract: The aim of this study was to evaluate the influence of sow body reserves at weaning and body reserve losses during the first lactation on the second litter size (SLS). A number of 1222 females which reached the second parity without failures such as return to estrus after insemination, abortion or failure to farrow, were analyzed. Measurements of body weight (BW), backfat thickness (BT) and body condition score (BCS) were taken within 24h after farrowing and on the weaning day. Body fat and body protein mass at first weaning and their losses during lactation were estimated based on BW and BT. The lactation length, the weaning-to-estrus interval (WEI) and the number of weaned piglets were on average 19.6days, 5.5days and 10.5 piglets, respectively. During lactation, the sows had on average a reduction of 18.6kg (9%) in BW, 3.1mm in BT and 0.8 in BCS. In the first and second farrowings there were on average 12.4 and 9.7 total born piglets, respectively. Females with more than 178kg, BT≥16mm or body fat≥21% at weaning had a higher SLS (P<0.05). Sows with a lipid:protein ratio at weaning >1.40 had more piglets (P<0.05) than those with a ratio <1.22. Females in the categories of high BCS (≥3.0) or high body protein (>15%) at weaning had more piglets in the second birth compared to females with a BCS≤2 or body protein ≤14% (P<0.05). Smaller SLS (P<0.05) was observed in sows with a weight loss >10%, body protein loss >10%, body fat loss >20% or a BCS loss≥1.0 point. When sows were categorized into two groups of BW at farrowing—low (167–206kg) or high (207–245kg), higher SLS (P<0.05) was observed in sows losing more than 8% of BW or 9% of protein mass. The loss of <22% in fat mass increased the SLS in sows of high BW (P<0.05) but not in those of low BW at farrowing. In conclusion, SLS is affected by absolute body reserves at weaning and by their mobilization during lactation indicating the importance of achieving an adequate body condition at parturition and of optimizing the feed intake in lactating primiparous sows.

Study on functional longevity of Tunisian Holstein dairy cattle using a Weibull proportional hazard model

2010-06-15

Abstract: Records of functional longevity (FL), from first calving to last recording (or culling), of 36,888 Tunisian Holstein cows in 169 herds were studied using survival analysis. Using a Weibull proportional hazard model, the influences of age at first calving, herd–year–season, lactation number–stage of lactation, milk production within the herd and year, annual change in herd size and random genetic effect of sire on FL were studied. Besides a random time-dependent effect of herd–year–season, the model included fixed effects of parity and stage of lactation, within herd and parity production level (all time-dependent), and age at first calving (time-independent). All factors had a significant effect on FL at a level of P<0.001. Milk yield was by far the most important factor influencing FL and the hazard increased as the milk production decreased. Within the first three lactations, the relative culling risk increased stepwise with lactation stage. The highest risk of culling was found for cows at the beginning and at the end of the first lactation and at the end of any other lactation. The risk of culling decreased with parity.

Association of apolipoprotein B gene with body growth and fatness traits in Iranian commercial broiler lines

2010-06-15

Abstract: Apolipoproteins play a central role in the assembly, secretion, processing, and catabolism of lipoproteins. Apolipoprotein B (APOB) is the primary apolipoprotein of low-density lipoproteins (LDL), and is responsible for carrying cholesterol to tissues. The current study was designed to investigate the associations of apoB gene polymorphism on chicken body growth and fatness traits. Genomic DNAs were extracted from 400 chickens from four different commercial broiler lines. Two polymorphisms of the apoB gene were found with restriction fragment length polymorphisms. The association between these polymorphisms and their haplotypes with chicken growth and fatness traits were analyzed using both single marker and haplotype analysis. Polymorphisms in apoB gene and haplotypes were significantly (P<0.1) associated with body growth and fatness traits. This research suggests that apoB gene could be a candidate locus or linked to a major gene(s) that affects growth and fatness traits in the chicken.

Genetic diversity in Tunisian dromedary (Camelus dromedarius) populations using microsatellite markers

M. Ould Ahmed, F. Ben Salem, S. Bedhiaf, B. Rekik, M. Djemali — 2010-06-28

Abstract: Genetic diversity and relationships among three camel populations from three different geographic regions (Kebili, Medenine and Tataouine) in the South of Tunisia were estimated using a panel of six microsatellite markers. The total number of observed alleles across the three populations was 28. The mean number of alleles per locus was 3.33, 4, 4.17, and 4.67 for Kebili, Medenine, and Tataouine and across populations, respectively. The mean observed heterozygosity was 0.43, 0.43, 0.53 and 0.46 for Kebili, Medenine, and Tataouine and across populations, respectively. Observed heterozygosity values were lower than their respective expected heterozygosities (0.52, 0.57, 0.62 and 0.60). The mean estimates of F statistics were FIT=0.27, FIS=0.19 and FST=0.09. These values were significantly different from zero (p<0.05) and suggest a moderate differentiation of the camel population. The value of FST indicates that approximately 91% of the total genetic variation originates from differences among individuals within populations. Dromedaries in this study can be grouped into two distinct genetic entities: The Nefzawa (Kebili) and the Aaradh populations.

Possible association of bovine chromosome 5 markers with growth and fat traits in Hereford cattle raised under extensive conditions

2010-06-28

Abstract: Bovine chromosome 5 has been widely studied because several QTLs have been detected there, in particular for growth and fat traits. Even though most of the beef is produced under pasture based conditions, only little research has focused on this kind of systems. Two QTL regions, neighboring the Myogenic factor 5 gene, and Insulin-like Growth Factor 1 (IGF1) gene, were selected. Within them, four BTA5 microsatellites (BP1, ETH10, IGF1 and RM029) were used to establish their association with growth and fat traits in a pasture based feeding system. The Estimated Breeding Values tested were: 400 (W400) and 600Days Weight (W600), Rib Eye Area (REA), Rib Fat, Rump Fat, and Intra Muscular Fat. For growth traits significant associations (p≤0.05) between BP1 and REA, and between IGF1 and W600, were detected. For fat traits significant association (p≤0.05) between ETH10 and Rib Fat and Rump Fat was detected. When considering a pair of closer marker genotypes, IGF1/ETH10 was significantly associated (p≤0.05) with W400 and W600. These results show that QTL for growth and fat traits that were previously reported in two regions of BTA5, are also expressed in a commercial pasture based system, where animals are not always fed to express their maximum genetic potential.