Changes in light intensity during the rearing period can influence egg production in domestic fowl     

Leeson S  Lewis PD 《British poultry science》2004,45(3):316-319

1. A total of 240 Shaver White and 240 ISA Brown pullets that had been reared in multi-bird cages on a 10-h photoperiod, and maintained at a light intensity of 3 or 25 lux, or changed from 3 to 25 lux or from 25 to 3 lux at 9 or 16 weeks of age, were moved into individual-bird cages at 20 weeks and transferred to 15-h photoperiods at 25 lux. 2. In both breeds, birds transferred from 3 to 25 lux at 16 or 20 weeks laid significantly more eggs than birds maintained on the brighter intensity from one day or increased to it at 9 weeks. 3. Mean egg weight, shell deformation, albumen height, feed intake and body weight gain in lay were not significantly affected by the light intensity treatments during the rearing period. There was, however, a small, but significant, negative correlation of egg numbers with mean egg weight, although this only partially explained the difference in egg numbers. The differences in egg production were unrelated to rate of sexual maturation.  相似文献   

Constant photoperiods and sexual maturity in broiler breeder pullets   总被引：2，自引：2，他引：0  

Lewis PD  Backhouse D  Gous RM 《British poultry science》2004,45(4):557-560

1. Broiler breeder pullets were maintained on 10-, 11-, 12-, 13-, 14- or 16-h photoperiods to determine the effect of constant photoperiods on sexual development in broiler breeders. The birds were fed to achieve a 2100 g body weight at approximately 17 or 20 weeks to see if the photosexual response was modified by rate of growth. 2. In both body weight groups, pullets maintained on 10h were the first to reach sexual maturity (50 eggs/100 bird-d), and these and the 11-h pullets matured significantly earlier than any of the other photoperiod groups. Pullets maintained on 13 or 14 h matured latest, at about 3 weeks after the 10-h pullets, though both were only marginally later than the 12- or 16-h birds. These differences in maturation probably reflect the different rates at which photorefractoriness is dissipated in broiler breeders reared on photoperiods that vary in their degree of stimulatory competence. 3. There were no significant interactions among the photoperiods and the ages at 2100 g; faster-growing birds consistently matured about 10 d earlier than conventionally grown pullets.  相似文献   

International disease surveillance     

Lewis CJ  Michell AR 《The Veterinary record》2004,154(5):156; discussion 156

  相似文献   

Intrapelvic granuloma formation six years after total hip arthroplasty in a dog     

Freeman CB  Adin CA  Lewis DD  Ginn PE 《Journal of the American Veterinary Medical Association》2003,223(10):1446-9, 1433

A 9-year-old Golden Retriever that had undergone left total hip arthroplasty 6 years previously was evaluated because of constipation and tenesmus. Abdominal radiography and ultrasonography revealed a large intrapelvic mass that was contiguous with a mass of polymethyl methacrylate that had been extruded through a defect in the medial wall of the acetabulum at the time of total hip arthroplasty. Clinical signs resolved following resection of the mass and associated polymethyl methacrylate from the pelvic canal. Results of histologic examination of the mass were consistent with a diagnosis of foreign body granuloma, most likely secondary to particulate debris. There was no clinical or radiographic evidence of aseptic loosening of the acetabular or femoral components, and the mass may have represented a response to wear debris.  相似文献   

Culling of wild red deer     

Thomas L  Allen T 《The Veterinary record》2003,152(26):815; author reply 815-815; author reply 816

  相似文献   

Toxicity of cadmium and zinc to the cercarial activity of Diplostomum spathaceum (Trematoda: Diplostomidae)     

Morley NJ  Crane M  Lewis JW 《Folia parasitologica》2003,50(1):57-60

The toxicity of cadmium and zinc at concentrations ranging from 0.1 to 100 microg/l was investigated against the activity of Diplostomum spathaceum (Rudolphi, 1819) cercariae. Over a 24 h exposure period a significant reduction in cercarial activity occurred in solutions of cadmium, zinc, and a mixture of cadmium and zinc at all concentrations. Reduced cercarial activity also occurred in all toxicant solutions compared with controls after only 6 h exposure indicating that cercariae were vulnerable during the period of maximum cercarial infectivity (0-5 h). The mechanisms of metal toxicity and their importance to parasite transmission are discussed.  相似文献   

Matched concurrent case-control study of risk factors for feather pecking in hens on free-range commercial farms in the UK   总被引：1，自引：0，他引：1  

Nicol CJ  Pötzsch C  Lewis K  Green LE 《British poultry science》2003,44(4):515-523

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.  相似文献   

Growth,carcass traits,and plasma amino acid concentrations of gilts fed low-protein diets supplemented with amino acids including histidine,isoleucine, and valine   总被引：6，自引：0，他引：6  

Figueroa JL  Lewis AJ  Miller PS  Fischer RL  Diedrichsen RM 《Journal of animal science》2003,81(6):1529-1537

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.  相似文献   

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     

Halling KB  Lewis DD  Cross AR  Sammy RJ  Rapoff AJ 《Veterinary surgery : VS》2003,32(4):324-335

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.  相似文献   

The Banfield Education Program     

Lewis HB  Novak W 《Journal of veterinary medical education》2003,30(1):33-40

  相似文献