Influence of stocking density on the performance, carcass characteristics and selected welfare indicators of broiler chickens     

Thomas DG  Ravindran V  Thomas DV  Camden BJ  Cottam YH  Morel PC  Cook CJ 《New Zealand veterinary journal》2004,52(2):76-81

AIM: To compare the effects of four stocking densities (5, 10, 15 or 20 birds per m2) on the performance, carcass characteristics and selected welfare indicators of broiler chickens. METHODS: A total of 756 day-old male broiler chicks were assigned as six replicates of 13, 25, 38 and 50 birds per pen, to stocking densities of 2,000, 1,000, 667 and 500 cm2 floor space per bird, respectively. The birds were housed in floor pens in an environmentally controlled room. Normal commercial diets were fed ad libitum and fresh water was freely available throughout the 5-week study period. Liveweights of birds and feed intake were recorded at weekly intervals. Data on carcass parameters and welfare indicators (moisture, gait scores, feather scores, breast and hip lesions, and foot pad and hock burns) were obtained on Day 35. Adrenal glands were removed at slaughter, weighed and examined histologically to determine the total proportion of cortical and medullary tissues. RESULTS: During the study, the birds at the lowest density grew faster (p<0.001-0.01) and consumed more (p<0.001- 0.01) feed than those at the other three stocking densities. The liveweight gains and feed intake of birds reared at densities of 10, 15 and 20 birds per m2 were similar (p=0.11-0.83 and p=0.17-0.57, respectively). Stocking density had no influence on the feed/weight gain, mortality or carcass characteristics. No breast or hip lesions were observed in carcasses from any of the groups. The weight and structure of the adrenal glands were similar across all groups although the staining of medullary tissue of birds was most intense in the highest stocking density group. As stocking density increased, so did moisture and gait score, hock and foot pad burn scores, and the feather score was adversely affected. CONCLUSIONS: The data showed that the relationship between stocking density and productivity traits was not linear in nature, in accordance with other studies. Under the conditions of the current study, the performance, mortality and carcass characteristics of broilers grown at densities of 10, 15 and 20 birds per m2 were similar. There were some welfare implications at high population densities as indicated by adverse effects on litter quality, gait scores and the incidence of hock and foot pad burns.  相似文献   

Breed does not affect the association between murmur intensity and disease severity in dogs with pulmonic or subaortic stenosis     

M. Rishniw  D. Caivano  D. Dickson  S. Swift  C. Rouben  S. Dennis  C. Sammarco  J. Lustgarten  I. Ljungvall 《The Journal of small animal practice》2019,60(8):493-498

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Prospective study of dilated cardiomyopathy in dogs eating nontraditional or traditional diets and in dogs with subclinical cardiac abnormalities     

Lisa Freeman  John Rush  Darcy Adin  Kelsey Weeks  Kristen Antoon  Sara Brethel  Suzanne Cunningham  Luis Dos Santos  Renee Girens  Robert Goldberg  Emily Karlin  Darleen Lessard  Katherine Lopez  Camden Rouben  Michelle Vereb  Vicky Yang 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2022,36(2):451

BackgroundRecent studies have investigated dogs with presumed diet‐associated dilated cardiomyopathy (daDCM), but prospective studies of multiple breeds are needed.Hypothesis/ObjectivesTo evaluate baseline features and serial changes in echocardiography and cardiac biomarkers in dogs with DCM eating nontraditional diets (NTDs) or traditional diets (TDs), and in dogs with subclinical cardiac abnormalities (SCA) eating NTD.AnimalsSixty dogs with DCM (NTD, n = 51; TDs, n = 9) and 16 dogs with SCA eating NTDs.MethodsEchocardiography, electrocardiography, and measurement of taurine, cardiac troponin I, and N‐terminal pro‐B‐type natriuretic peptide were performed in dogs with DCM or SCA. Diets were changed for all dogs, taurine was supplemented in most, and echocardiography and cardiac biomarkers were reassessed (3, 6, and 9 months).ResultsAt enrollment, there were few differences between dogs with DCM eating NTDs or TDs; none had low plasma or whole blood taurine concentrations. Improvement in fractional shortening over time was significantly associated with previous consumption of a NTD, even after adjustment for other variables (P = .005). Median survival time for dogs with DCM was 611 days (range, 2‐940 days) for the NTD group and 161 days (range, 12‐669 days) for the TD group (P = .21). Sudden death was the most common cause of death in both diet groups. Dogs with SCA also had significant echocardiographic improvements over time.Conclusions and Clinical ImportanceDogs with DCM or SCA previously eating NTDs had small, yet significant improvements in echocardiographic parameters after diet changes.  相似文献