Metabolic response of horses to a high soluble carbohydrate diet: effects of low-intensity submaximal exercise and sodium bicarbonate supplementation.     

P L Ferrante  J H Menninger  P A Spencer  D S Kronfeld 《American journal of veterinary research》1992,53(3):321-325

Four mares fed a low fiber, high soluble carbohydrate diet were used in a crossover design to evaluate the effects of dietary sodium bicarbonate (NaHCO3) supplementation during daily low-intensity submaximal working conditions. Mares were fed the diet at 1.7 times the maintenance energy requirement for mature horses at work. The horses tolerated the diet well and had no clinical abnormalities. Resting venous blood bicarbonate (HCO3), standard HCO3, and base excess (BE) concentrations significantly (P less than 0.05) increased with NaHCO3 supplementation, but no significant changes in resting venous blood pH or carbon dioxide tension (PCO2) were recorded. Venous blood HCO3, standard HCO3, BE, hemoglobin, and heart rate were significantly (P less than 0.05) increased and plasma lactate concentration was significantly (P less than 0.05) decreased in the control horses and in the horses given the NaHCO3 supplement during low-intensity submaximal exercise. There were no significant changes in venous blood pH, PCO2, or plasma protein concentration with exercise. Venous blood HCO3, standard HCO3, and BE concentrations were significantly (P less than 0.05) greater during submaximal exercise in horses given the NaHCO3 supplement. There were no significant differences in plasma lactate or total protein concentrations, blood pH, PCO2, or hemoglobin concentration between the 2 groups during exercise.  相似文献   

A survey of northern Victorian dairy farmers to investigate dairy calf management: colostrum feeding and management          下载免费PDF全文

AJ Phipps  DS Beggs  AJ Murray  PD Mansell  MF Pyman 《Australian veterinary journal》2018,96(4):101-106

Objectives

To describe colostrum management practices carried out in northern Victorian dairy herds and to identify weaknesses in these areas that may affect calf health and welfare by comparing the results with the current industry recommendations

Methods

A questionnaire to obtain information about colostrum management and calf‐rearing practices was sent to commercial dairy farming clients of Rochester Veterinary Practice between June and September 2013. The questionnaire consisted of a general herd overview and colostrum harvesting practices.

Results

The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) time of removal calf from the dam, (2) relying on calf suckling colostrum from the dam to achieve adequate passive transfer, (3) failing to supplement calves with colostrum, (4) feeding inadequate volumes of colostrum, (5) delayed colostrum harvesting, (6) pooling of colostrum, (7) failing to objectively assess colostrum quality or relying on visual assessment and (8) storing colostrum for a prolonged periods of time at ambient temperatures.

Conclusion

The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.

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Insulin-like growth factor I in growing thoroughbreds     

Staniar WB  Kronfeld DS  Akers RM  Harris PA 《Journal of animal physiology and animal nutrition》2007,91(9-10):390-399

The objective of this longitudinal study was to characterize growth and plasma insulin-like growth factor I (IGF-I) concentrations in pasture-raised thoroughbreds fed two sources of dietary energy. Mares and foals were randomly assigned to either a sugar and starch (SS) or fat and fibre (FF)-rich feed, and plasma IGF-I and growth were measured once a month from 1 to 16 months of age. These dependent variables were also compared with day length and ambient temperature. There was an association between plasma IGF-I concentration and average daily gain (ADG) (r = 0.32, p < 0.001). There were also clear seasonal patterns in both ADG and plasma IGF-I, with high values in June and May, and a low value in March. Plasma IGF-I and ADG were positively associated with day length and temperature. Plasma IGF-I was never higher (p > 0.10) in the FF group when compared with the SS group, and was higher in the SS group during a rapid growth phase in the spring of year 2 (p < 0.10). The results establish an association between ADG and IGF-I in the horse and indicate that environment and age may influence this relationship. In addition, plasma IGF-I is influenced by dietary energy source at particular times of year. This link has important implications in designing feeding management strategies that are aimed at addressing skeletal development.  相似文献   

Concerned about use of BST in dairy cattle     

Kronfeld DS 《Journal of the American Veterinary Medical Association》2001,219(5):591-592

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Obesity and diet affect glucose dynamics and insulin sensitivity in Thoroughbred geldings     

Hoffman RM  Boston RC  Stefanovski D  Kronfeld DS  Harris PA 《Journal of animal science》2003,81(9):2333-2342

Insulin resistance is considered a risk factor in obesity, laminitis, exertional rhabdomyolysis, and osteochondrosis. The objective was to use the minimal model to estimate glucose effectiveness (Sg) and insulin sensitivity (Si) in nonobese to obese horses initially adapted to forage only, then adapted to forage plus supplements rich in starch and sugar (SS) or fiber and fat (FF). Ten Thoroughbred geldings, with BCS of 5 (nonobese), 6 (moderately obese), and 7 to 8 (obese), were adapted to pasture and hay, allocated to two groups, and fed SS or FF in a switch-back design with 8 wk of adaptation. Modified frequent-sampling i.v. glucose tolerance tests were applied after adaptation to forage, SS, and FF. For the tolerance tests, horses were kept in stalls overnight and provided hay, and venous catheters were placed the next morning. Baseline samples were collected, 0.3 g of glucose/kg of BW was given i.v., and blood was sampled at 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, and 19 min. At 20 min, 30 mU of insulin/kg of BW was given, followed by sampling at 22, 23, 24, 25, 27, 30, 35, 40, 50, 60, 70, 80, 90, 100, 120, 150, and 180 min. Plasma was analyzed for glucose and insulin, and Si, Sg, acute insulin response to glucose, and the disposition index were calculated. Normality was tested using the Shapiro-Wilk statistic. Body condition effects were analyzed using a mixed model with repeated measures. Diet effects were analyzed using a Wilcoxon signed rank test. The Sg was higher in obese than nonobese (P = 0.003) and moderately obese (P = 0.007) horses; Si was lower in obese than nonobese (P = 0.008) horses, and acute insulin response to glucose was higher in obese than nonobese (P = 0.039) horses. Effects of diet were likely confounded by body condition, but horses had lower Si (P = 0.066) when fed SS compared with FF, especially when nonobese. In conclusion, the minimal model effectively estimated Sg, Si, acute insulin response to glucose, and disposition index in horses. Obese geldings were insulin-resistant and seemed to rely primarily on Sg for glucose disposal. Feeding a diet rich in sugar and starch decreased insulin sensitivity of horses. Maintenance of body condition and avoidance of grain-based meals rich in sugar and starch would be beneficial to decrease the risk of developing insulin resistance and associated metabolic syndromes in horses, especially for horses at risk for these syndromes.  相似文献   

Effect of Exposure to Heatwave During Blastocyst Formation on Reproductive Performance of Female Rabbits     

F Marco‐Jiménez  C Naturil‐Alfonso  DS Peñaranda  E Jiménez‐Trigos  FJ García‐Diego  JS Vicente 《Reproduction in domestic animals》2014,49(4):629-635

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Alkanes as internal markers to estimate digestibility of hay or hay plus concentrate diets in horses.   总被引：8，自引：0，他引：8  

A L Ordakowski  D S Kronfeld  J L Holland  B J Hargreaves  L S Gay  P A Harris  H Dove  D Sklan 《Journal of animal science》2001,79(6):1516-1522

Dry matter intake (DMI), dry matter digestibility (DMD), and fecal output (FO) are difficult to measure directly in the field, and indirect methods using external and internal markers have thus been developed. An experiment was conducted consisting of two digestion trials with two periods in each trial to examine the use of five odd-chain alkanes (C25 to C33) of plant cuticular wax as internal markers to estimate DMD of hay or hay plus concentrate diets in horses. Eight mature Thoroughbred geldings were housed in 4- x 4-m stalls and randomly assigned to one of two mixed grass/legume hays (Diets 1 and 2) in Trial 1 and to mixed grass/legume hay plus one of two concentrates (Diets 3 and 4) in Trial 2. After the first 12-d period was conducted, dietary assignments for each group were switched for the second period in each trial. Each period consisted of a dietary accommodation from d 1 to 7 and total fecal collection from d 8 to 11. Results indicated that fecal recoveries of odd-chain alkanes were 88 to 90% for Diet 1, 75 to 92% for Diet 2, 71 to 81% for Diet 3, and 71 to 82% for Diet 4. Alkane recoveries were not related to alkane chain lengths. Digestibilities calculated from alkane concentration data adjusted using the mean fecal recovery of individual odd-chain alkanes (DA1) were not significantly different from the digestibilities estimated from total collection (DTC) for Diets 1 and 2 in Trial 1 and Diets 3 and 4 in Trial 2. When adjustment was based on the mean recovery of all alkanes (DA2; estimated by linear regression), all DA2 estimates for horses offered all diets were similar to DTC. Results indicate that accurate mean estimates of DMD can be obtained by using plant wax alkane markers and adjusting for the mean recovery of five odd-chain alkanes in a diet.  相似文献   

Dietary aspects of developmental orthopedic disease in young horses     

D S Kronfeld  T N Meacham  S Donoghue 《Veterinary Clinics of North America: Equine Practice》1990,6(2):451-465

The clinician may choose between two approaches to nutritional intervention. One is to evaluate the ration and make a painstaking effort to identify those specific factors operating in a particular case, then correct them. The second is to evaluate the ration, inspect for obvious aberrations, and, if finding none, proceed with no further delay to formulate an optimal diet, or a series, for the animals, and design a feeding program to suit farm management. Veterinarians should counsel clients on the possible or probable consequences of level of feeding on growth rate and clinical expression of DOD. In our view, retardation of growth rate by feeding poor quality hay is irresponsible. At present, we suggest that the new approach to retarded growth in weanlings and yearlings--a carefully formulated diet that specifically restricts starch and protein while supplying NRC minimum requirements of other essential nutrients--should be confined to selected individuals and be conducted under strict professional supervision.  相似文献   

Excitation Gap in the Normal State of Underdoped Bi2Sr2CaCu2O8+delta     

AG Loeser  Z Shen  DS Dessau  DS Marshall  CH Park  P Fournier  A Kapitulnik 《Science (New York, N.Y.)》1996,273(5273):325-329

Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.  相似文献   

Consumer protection, veterinary medicine, and new animal drugs     

D S Kronfeld 《Journal of the American Veterinary Medical Association》1972,161(11):1395-1400

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