Prosthetic Coxofemoral Joint Replacement in the Goose (Anser Sp.): II. Histologic and Mechanical Interface Evaluations

The interfacial tissue-implant healing reactions have been investigated in the goose to evaluate its suitability as an animal model for joint replacement implant studies. After various implantation periods, geese with one coxofemoral replacement hemiarthroplasty were evaluated for their gait performance and then sacrificed. The implantation sites and femora with implants were subjected to histologic studies, and the interfacial shear strength between the bone and implant was measured. The results were compared with findings reported in the literature on dog and man. Direct bone apposition was found in two geese with a firmly fixed implant. A connective tissue capsule surrounded those seven implant stems that were found to sit loosely in the femoral canal. Whereas the histologic findings were comparable to findings in dog and man, the interfacial shear stress was somewhat lower in the goose. Because of the histopathologically comparable findings of interfacial healing, the goose appears to present a suitable model to study bone implant tissue reactions. Further studies are necessary to determine seasonal-, age-, and sex-related bone tissue differences in the goose.     

Dietary fructan carbohydrate increases amine production in the equine large intestine: implications for pasture-associated laminitis

Pasture-induced laminitis in the horse is associated with the overconsumption of fermentable carbohydrate, in the form of simple sugars, fructans, or starch. The fermentation of carbohydrate in the cecum and large intestine results in the production of lactic acid and other toxins or "laminitis trigger factors." Vasoactive amines have been suggested as possible initiating factors. The aim of this study was to feed a commercially available form of fructan carbohydrate (inulin, 3 g/kg of BW per day) to normal ponies and to ponies predisposed to laminitis, to mimic a change from a basal hay diet to lush spring-summer pasture. Five normal and 6 laminitis-prone, native-breed ponies were acclimated to a basal hay diet before the inclusion of inulin and chopped dried grass. Blood samples, fecal samples, and foot temperature measurements were taken throughout the study. Amines were measured in the feces and plasma by HPLC and liquid chromatography-mass spectrometry, respectively. The pH of the fecal samples decreased from 6.89 +/- 0.11 on the hay diet to a minimum of 6.18 +/- 0.11 with the addition of inulin (P <0.05). An increase was observed in the fecal concentrations of a number of amines, including tryptamine (2.5-fold increase, P <0.05) and tyramine (2-fold increase, P <0.05). No changes were noted in plasma amine concentrations or plasma D- or L-lactate, indicating that there may be a threshold of hindgut pH change before mucosal damage can result in the release of these factors into the circulation. No differences in pH or any of the measured compounds were observed between the group of normal ponies and those predisposed to laminitis. This indicates that differences in the intestinal microflora do not account for this predisposition. However, the results from this study indicate that moderate increases in dietary fructan carbohydrate can produce increases in bacterial fermentation products and other compounds in the large intestine, which may be relevant to the pathogenesis of acute laminitis in ponies on pasture.     

Effects of temperature on power output and contraction kinetics in the locomotor muscle of the regionally endothermic common thresher shark (Alopias vulpinus)

The common thresher shark (Alopias vulpinus) is a pelagic species with medially positioned red aerobic swimming musculature (RM) and regional RM endothermy. This study tested whether the contractile characteristics of the RM are functionally similar along the length of the body and assessed how the contractile properties of the common thresher shark compare with those of other sharks. Contractile properties of the RM were examined at 8, 16 and 24?°C from anterior and posterior axial positions (0.4 and 0.6 fork length, respectively) using the work loop technique. Experiments were performed to determine whether the contractile properties of the RM are similar along the body of the common thresher shark and to document the effects of temperature on muscle power. Axial differences in contractile properties of RM were found to be small or absent. Isometric twitch kinetics of RM were ~fivefold slower than those of white muscle, with RM twitch durations of about 1?s at 24?°C and exceeding 5?s at 8?°C, a Q(10) of nearly 2.5. Power increased approximately tenfold with the 16?°C increase in temperature, while the cycle frequency for maximal power only increased from about 0.5-1.0?Hz over this temperature range. These data support the hypothesis that the RM is functionally similar along the body of the common thresher shark and corroborate previous findings from shark species both with and without medial RM. While twitch kinetics suggest the endothermic RM is not unusually temperature sensitive, measures of power suggest that the RM is not well suited to function at cool temperatures. The cycle frequency at which power is maximized appeared relatively insensitive to temperature in RM, which may reflect the relatively cooler temperature of the thresher RM compared to that observed in lamnid sharks as well as the relatively slow RM phenotype in these large fish.     

Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations

Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate (2 mg kg⁻¹ of body weight (BW) d⁻¹, on day 1 to 14), progesterone (0.10 mg kg⁻¹ of BW, on day 1 to 7), flumethasone (0.03 mg kg⁻¹ of BW, on day 18 to 20) and recombinant bovine somatotropin (rbST; 500 mg per cow, on day 1, 6, 16 and 21). At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artificially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk (DIM) did not differ between the first and second induced lactations ((9 710 ±1 728) vs. (9 309±2 150) kg; mean±SD). Total milk yield ((12 707±3 406) vs. (12 306±4 218) kg; mean±SD) and lactation length ((405±100) vs. (410±91) d; mean±SD) were not different between the first and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon (n=334), 18-mon (n=164) and 29-mon (n=22) lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl (Y= ab^1/xx^c), Wood (Y=ax^b exp(cx)) and Dhanoa (Y=ax^(bc)exp(cx)) models were equally suitable to describe 12-mon lactations. An exponential model with five parameters (Y=exp(a+bx+cd²+e/x)) showed the best fit for milk yield for 18-mon lactations. The rational model (Y=a+bx/1+cx+dx²) was found to produce the closest fit for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the first cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artificial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for fitting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation.     

如何提高仔猪饲料中小麦的利用率

<正>用最具成本效益的方法配制猪饲料是提高养猪场经济利润的一种重要手段。但是,具有最低成本的饲料配制方法往往会就几种主要饲料原料的饲喂价值进行过于简单的假设,同时还假定各饲料原料的养分具有相加性。这种情况会因饲料添加剂的加入而进一步混乱,或受到潜在的损害,因为饲料添加剂旨在使饲料释放更多的能量和/或氨基酸。因此,饲料配方师不得不充分确保某种添加剂将持