Matched concurrent case-control study of risk factors for feather pecking in hens on free-range commercial farms in the UK

1. The aim of the study was to compare the management and husbandry of free-range flocks in the UK where feather pecking was either present (case) or absent (control). 2. One hundred flocks were enrolled into a concurrent case-control study: 50 where birds had recently started feather pecking, and 50 matched control flocks where birds of the same age had not started feather pecking. 3. Information was obtained from a detailed interview with the flock manager, and by direct inspection of the flock, house and range. 4. Initial univariate analyses revealed that case flocks were more likely to comprise ISA Brown than Lohmann, were more likely to be restricted from litter areas to prevent floor eggs, and were less likely to use the outside range. 5. Cluster analysis indicated that feather pecking was not associated with any particular husbandry system. 6. The only influential risk factor significant in the multivariable conditional logistic regression analysis was use of the outdoor range. The risk of feather pecking was reduced 9-fold in flocks where more than 20% of birds used the range on sunny days (odds ratio = 0.12). Use of the range was positively associated with the presence of trees and/or hedges on the range.     

Growth,carcass traits,and plasma amino acid concentrations of gilts fed low-protein diets supplemented with amino acids including histidine,isoleucine, and valine

Three experiments were conducted to determine the fifth-limiting amino acid for growing pigs in an 11% CP, corn-soybean meal diet. In each experiment, 36 gilts (initial weight 19.5, 21.9, and 21.0 kg, respectively) were penned individually and fed one of six diets in a randomized block design for 35 d. Diets containing 16, 12, and 11% CP were fed in each experiment. All 12 and 11% CP diets were supplemented with lysine, tryptophan, threonine, and methionine to provide the same total concentrations as those in the 16% CP diet. In Exp. 1, the 11% CP diet was supplemented with isoleucine, valine, or isoleucine + valine to concentrations equal to those in the 16% CP diet. In Exp. 2, the 11% CP diet was supplemented with histidine, histidine + valine, or histidine + isoleucine + valine. In Exp. 3, the 11% CP diet was supplemented with valine, histidine + valine, or isoleucine + valine. Gilts were allowed free access to feed and water. In all experiments, ADG and feed efficiency (G/F) were reduced (P < or = 0.07) as dietary protein was reduced. Supplementation of isoleucine alone further reduced (P < 0.05) ADG, ADFI, G/F, and fat-free lean gain. In contrast, supplementation of valine alone resulted in numerical increases in ADG and ADFI in two experiments, although the differences were not significant (P > 0.05). Supplementation with histidine and valine together resulted in growth performance equal to or greater than that of pigs fed the 12% CP diet, but less than that of pigs fed the 16% CP diet. Supplementation of isoleucine and valine together resulted in better growth performance (P < 0.05) than supplementation of either amino acid alone. In two experiments (Exp. 1 and 3), supplementation of the 11% CP diet with isoleucine and valine together resulted in ADG that were not significantly different (P > 0.05) from those of pigs fed the 16% CP diet. Supplementation of all three amino acids (Exp. 2) did not improve performance over supplementations with histidine and valine. Plasma urea concentrations were reduced (P < 0.05) as dietary protein was lowered from 16 to 12%. Additions of crystalline amino acids did not affect plasma urea levels. Plasma amino acid concentrations reflected the dietary additions of crystalline amino acids, but did not assist in the identification of the sequence of limiting amino acids. These data suggest that valine is the fifth-limiting amino acid and that either histidine or isoleucine is the sixth-limiting amino acid in an 11% CP diet.     

Biomechanical comparison of a circular external skeletal fixator construct to pin and tension band wire fixation for the stabilization of olecranon osteotomies in dogs: a cadaveric study

OBJECTIVE: To compare anatomic reduction and the biomechanical properties of a circular external skeletal fixator (CESF) construct to pin and tension band wire (PTBW) fixation for the stabilization of olecranon osteotomies in dogs. STUDY DESIGN: Cadaveric study. ANIMALS: Forelimbs from 12 skeletally mature mixed-breed dogs, weighing 23 to 28 kg. METHODS: An olecranon osteotomy was stabilized with either a CESF construct or PTBW fixation. A single distractive load to failure was applied to each specimen through the triceps tendon. Osteotomy reduction and biomechanical properties were compared between fixation groups. RESULTS: Reduction was not significantly different (gap: P =.171; malalignment: P =.558) between fixation groups. Osteotomies stabilized with the CESF had greater stiffness (P <.0001) and maximum load sustained (P <.0001) compared to PTBW fixation. There was no significant difference for yield load (P =.318) or for load at 1 mm of axial displacement (P =.997) between fixation groups. Failure of fixation occurred by bending of the intramedullary Steinmann pin and the fixation wires in the CESF specimens and by untwisting of the tension band wire knot with pullout and bending of the Kirschner wires in the PTBW specimens. CONCLUSIONS: Specimens stabilized with the CESF construct had similar reduction and yield load, greater stiffness and maximum load sustained, and less elastic deformation than specimens stabilized with PTBW fixation. CLINICAL RELEVANCE: The CESF construct may provide a biomechanically favorable alternative to PTBW fixation for stabilization of olecranon osteotomies in dogs, and its application warrants clinical investigation.     

Amino acid interactions in chick nutrition. 1. The interrelationship between lysine and arginine

A series of experiments has been conducted to investigate the specificity of the interaction between lysine and arginine in chick nutrition, in the light of the concept of agent and target advanced by Lewis (1965). Diets were designed in which the level of methionine, tryptophan, histidine, or threonine was appreciably inadequate, while the arginine concentration in each diet was marginally satisfactory. Excess lysine was added to these diets in a standard sequence.

The profound ill‐effects induced by excess lysine were, in all experiments, alleviated only by arginine and not by the amino acids originally limiting in the control diets. The findings support the existence of an unique relationship between lysine and arginine.     

Synthetic oestrogens in the production of roasting fowl. II. Dietary nutrient concentration and time of implantation

Three experiments have been carried out using broiler‐type birds reared beyond the normal broiler stage to 14 weeks of age. In the first experiment control cockerels were compared with birds injected with either a 15 mg. hexoestrol pellet or a 15 mg. pellet of diethylstilboestrol at 9 weeks of age: at this stage three diets of different nutrient density were offered. As the nutrient density was increased, food utilisation progressively improved and growth rates were raised. Hexoestrol implantation resulted in an increase in voluntary food intake of 23 per cent above the control whereas diethylstilboestrol implantation increased voluntary food intake by only 14 per cent. These increases in food intake were associated with proportional increases in live‐weight gain.

In a second experiment pullets received 15 mg. implants of hexoestrol at 64 days of age, and were then fed diets of different nutrient concentrations to 98 days of age. Live‐weight gain tended to improve as nutrient density was raised, and efficiency of food utilisation was inversely proportional to nutrient density.

In a third experiment male birds were reared from 70 to 119 days of age. Four different implantations with hexoestrol at various ages were compared: only in those receiving two implants was there any difference in performance. Six diets varying in energy level and protein level were offered. Growth rates improved as dietary protein levels were raised progressively from 13.3 to 16.3 per cent, though food utilisation was most efficient at 14.8 and 16.3 per cent crude protein. Growth rate was 7.6 per cent greater when the dietary energy level was raised from 3065 to 3275 kcal. metabolisable energy per kg.     

Adverse events diagnosed within three days of vaccine administration in dogs

OBJECTIVE: To determine incidence rates and potential risk factors for vaccine-associated adverse events (VAAEs) diagnosed within 3 days of administration in dogs. DESIGN: Retrospective cohort study. ANIMALS: 1,226,159 dogs vaccinated at 360 veterinary hospitals. PROCEDURE: Electronic records from January 1, 2002, through December 31, 2003, were searched for possible VAAEs (nonspecific vaccine reaction, allergic reaction, urticaria, or anaphylaxis) diagnosed within 3 days of vaccine administration. Information included age, weight, sex, neuter status, and breed. Specific clinical signs and treatments were reviewed in a random sample of 400 affected dogs. The association between potential risk factors and a VAAE was estimated by use of multivariate logistic regression. RESULTS: 4,678 adverse events (38.2/10,000 dogs vaccinated) were associated with administration of 3,439,576 doses of vaccine to 1,226,159 dogs. The VAAE rate decreased significantly as body weight increased. Risk was 27% to 38% greater for neutered versus sexually intact dogs and 35% to 64% greater for dogs approximately 1 to 3 years old versus 2 to 9 months old. The risk of a VAAE significantly increased as the number of vaccine doses administered per office visit increased; each additional vaccine significantly increased risk of an adverse event by 27% in dogs < or = 10 kg (22 lb) and 12% in dogs > 10 kg. CONCLUSIONS AND CLINICAL RELEVANCE: Young adult small-breed neutered dogs that received multiple vaccines per office visit were at greatest risk of a VAAE within 72 hours after vaccination. These factors should be considered in risk assessment and risk communication with clients regarding vaccination.     

Change in the effect of constant photoperiods on the rate of sexual maturation in modern genotypes of domestic pullet

1. Data for modern egg-type hybrids reared on constant daylengths show that, as expected, they mature more quickly than earlier genotypes. However, the constant photoperiod which gives earliest sexual maturity has not changed as a result of selection and is 10 h for both early and modern genotypes. 2. Further analysis showed that the rate of delay in sexual maturity for constant photoperiods above 10 h is similar for modern and for early hybrids (+0.29 d for each incremental one hour of photoperiod), the response of modern hybrids below 10 h (+4.22 d for each one-hour reduction in photoperiod) is more than double that of early hybrids (+1.71 d/h).     

The incidence of genotypes at codon 171 of the prion protein gene (PRNP) in five breeds of sheep and production traits of ewes associated with those genotypes

Scrapie is one of several transmissible spongiform encephalopathies of livestock. Disease susceptibility is linked to polymorphisms in the normal prion protein gene that encodes the mammalian prion precursor. Codon 171 of this gene is a major determinant of scrapie susceptibility. Selection for arginine (R) at codon 171 is encouraged by the USDA to decrease the incidence of scrapie. Objectives of this study were to determine the frequency of R allele variants at codon 171 in a sample of sheep from five breeds (Columbia, Hampshire, Rambouillet, Suffolk, and Targhee) and western white-faced commercial ewes and to determine whether the R allele is associated with ewe and lamb production traits. Genotyping was performed on 532 ewes and 901 lambs from the University of Wyoming flock, in addition to 820 rams from 52 sheep producers from Wyoming and surrounding areas, using a DNA mismatch assay that discriminated the R allele from others at codon 171. Genotyping was performed by DNA sequencing on 127 rams representing all breeds, except Hampshire from the USDA Sheep Experiment Station at Dubois, ID. The 171R allele was found in all five breeds and in the commercial western white-faced ewes. Genotype frequencies varied (P < 0.001) by breed in ewe and ram populations. Influence of R-allele frequency on ewe lambing records and individual lamb records was analyzed for Columbia (62, 161, 121), Hampshire (89, 193, 162), Rambouillet (87, 179, 133), Suffolk (67, 178, 161), and commercial sheep (227, 463, 324) for numbers of ewes, total number of ewe production records, and individual lamb records, respectively. Suffolk ewes without the R allele (non-R/non-R) gave birth to more (P or= 0.08) by ewe genotype. Lamb birth and weaning weights were not influenced (P >or= 0.12) by lamb genotype in any of the breeds or in the commercial flock. In this population, ultimate lamb production was only influenced by genotype at codon 171 in the Suffolk flock.