Administration of growth promotants with estrogenic activity via hastening closure of the growth plate could have an economic impact on lambs because closure results in ovine carcasses being classified as yearlings. Twelve wether lambs approximately 12 mo old were given silastic implants filled with estradiol-17 beta and allotted randomly to be slaughtered 30, 60, 90, or 220 d after implantation to determine time of growth plate closure in relation to date of implanting. Seven comparable wethers not implanted served as controls. Four wethers implanted at 2 mo of age and slaughtered 220 d later also were included. Implanted wethers had serum concentrations of estradiol averaging 13.9 pg/ml over the 220-d implant period; controls averaged 2.7 pg/ml. Estradiol implants increased carcass maturity scores but fat deposition was not altered. Growth plate widths decreased (P less than .05) as wethers grew older and implants were in place for longer periods of time. Metacarpal growth plates in 12-mo-old lambs were completely ossified 220 d after implanting, but control wethers and wethers implanted at 2 mo maintained growth plate widths. Neither metacarpal nor metatarsal bone lengths differed (P less than .05) between control and implanted wethers. Growth plate ossification was not complete until 570 d of age in implanted lambs, even though bone length had stopped increasing by 408 d. Therefore, even though estradiol and other growth stimulants with estrogenic activity increase rate of ossification of the metacarpal growth plate, bone length or mature size is not limited.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
One thousand twenty steers and heifers were used in six feeding trials to examine the influence of laidlomycin propionate on feedlot performance and to determine the most efficacious dietary concentrations of that ionophore. Cattle were fed diets ranging in energy content from 1.08 to 1.49 Mcal NEg/kg of DM. Laidlomycin propionate improved rate of gain and feed conversion in both steers and heifers. Improvements in performance were not evident when laidlomycin propionate was fed at only 3 mg/kg. However, both average daily gain and feed conversion were improved by laidlomycin propionate within the range of 6 to 12 mg/kg of DM (P less than .001). Feed consumption was not substantially affected by inclusion of laidlomycin propionate in the diet. Improvements in ADG and feed conversion were greater on lower-energy diets than on higher-energy diets, but both these performance characteristics were improved regardless of the type of diet fed. Average daily gain was maximized with laidlomycin propionate at 6 mg/kg, whereas improvements in feed conversion were sustained through 12 mg/kg. Carcasses of cattle fed diets containing 6 to 12 mg/kg of laidlomycin propionate weighed 7.3 kg more (P less than .001) than carcasses of cattle fed the control diets. Yield grade and quality grade were not affected by laidlomycin propionate (P greater than .05). 相似文献
One hundred twenty ewe and wether lambs were fed high (76% TDN, 12.3% crude protein) or low (70.6% TDN, 16.1% crude protein) energy diets and slaughtered at average ages of 261, 356 or 469 d. High planes of nutrition for lambs at 356 or 469 d of age resulted in heavier carcasses, thicker fat depth and higher flank streaking scores compared to lambs fed low planes of nutrition. Rib bone, break joint and overall maturity scores were not influenced (P greater than .05) by diet. Metacarpal and metatarsal bones from lambs fed high planes of nutrition were slightly longer and heavier and required more force to break (P less than .05) compared with bones from lambs fed low planes of nutrition. The majority of the ewes fed high or low planes of nutrition had fused growth plates and possessed spool joints by 469 d; none of the wethers had spool joints. An additional 27 wethers were slaughtered at an average of 480, 578 or 662 d. Rib bone, break joint and overall maturity scores were not different (P greater than .05) for animals fed the high or low energy diets, but bone weight and shaft break force values were higher for those fed high energy diets. At 662 d of age, only 20% of the wethers on each dietary regimen possessed fused growth plates. Overall, plane of nutrition in market-weight lambs and yearlings had very little influence on the presence or absence of a break joint or on other bone maturity scores.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
AIM: To determine the frequency and type of skin wounds encountered by New Zealand veterinarians in their equine patients, the duration and estimated costs of treatment as well as the expected outcomes for these wounds.
METHODS: An online survey was sent to all veterinarians registered with the New Zealand Equine Veterinary Association. The survey comprised questions on the location and experience of respondents, the number of wound-related cases in relation to the total equine caseload, the type and anatomical location of wounds treated, the frequency, duration and costs of treatments, the outcome of wound treatment and an estimate of the most common causes of death or euthanasia in their equine patients.
RESULTS: The survey response rate was 110/262 (41.9%). The median number of equine cases seen by respondents was 20 (interquartile range (IQR) 6–60) per month; of these, five (IQR 2–10) were wound related. Wounds ranked third after lameness and respiratory disease for the relative frequency with which respondents encountered them. Of 102 respondents 59 (58%) reported that their clients frequently treated wounds incurred by their horse without consulting a veterinarian. Wounds on the distal limb, whether involving only the skin or also deeper structures, were reported by 86/101 (85%) respondents as the most frequently encountered. Wounds in this location also incurred the longest treatment period and were the most prone to develop complications. Finally, wounds ranked second, after colic, as the most common cause of death/euthanasia in the veterinary respondents’ equine patients.
CONCLUSIONS: The data obtained via the survey indicate that skin wounds, particularly on the distal limb, are a common occurrence in horses in New Zealand and, when they involve structures underlying the skin, are costly and time-consuming to manage and may lead to decreased performance, retirement or euthanasia. Consequently, we recommend that more effort be devoted to the education of equine veterinarians and owners, and that appropriate research funds be allocated to help improve patient outcomes. 相似文献
Seven sheep weighing 34 to 41 kg, each, 3 steers and 1 heifer weighing 230 to 460 kg each, were experimentally, "overfed" (induced grain engorgement). The most significant changes occurred in ruminal ingesta pH, blood pH, packed cell volume (PCV), hemoglobin (Hb), carbon dioxide pressure (PCO2, total CO2 (volume %), blood D-lactic acid, blood HCO3, and base excess. There was no common denominator that was especially pathognomonic. 相似文献
Riley encased methodology (REM) was developed for the purpose of establishing mangroves along highenergy shorelines, revetments, and bulkheads where natural recruitment no longer occurs and where conventional planting methods are ineffective. The principles of REM include the processes of individual seedling isolation within tubular encasements and adaptation of the juvenile plant to the external environment of the restoration site. The success of REM results from specifications for encasement preparation, propagule or seedling selection, and positioning of both encasements and seedlings according to elevation and tidal regimes. 相似文献
Measurements from trees and plants of a BrazilianInga/maize/beans alleycrop experiment were assessed for their distributional properties for three years of the study. Results for the tree data were similar to those found in an earlier study. Results for the crop data demonstrated similarities between the distributions for alleycrops and solecrops, nonnormality shown by positive skewness and peaked distributions. Changes in the distributional shapes were demonstrated from year to year as soil nutrient depletion increased and as climatic variables fluctuated. Variation across the rows in the alley was often of a similar size to variation from plant to plant within the rows. Initial recommendations for analysis of such data are given on the basis of these results. 相似文献
Data from the tree components of fifteen agroforestry experiments were examined for patterns of variability, normality and correlation. Variances of data from intercropped plots were generally similar to those from monocropped plots and similar patterns for both types of plot were demonstrated over time. Non-normality of distributions were frequently indicated for both types of plot. Some examination was made of correlations between tree and crop components. Recommendations are made for suitable statistical analysis of such data and indications of experimental needs are given. 相似文献