Influence of dietary fat and time of hay feeding on growth and development of yearling horses |
| |
| Institution: | 1. Obstetrics, Gynecology and Andrology, Department for Small Animals and Horses, Vetmeduni Vienna, Austria;2. Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, Austria;3. Graf Lehndorff Institute, Vetmeduni Vienna, Neustadt (Dosse), Germany;1. Departamento de Fomento de la Producción Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, La Pintana, Santiago, Chile;2. Instituto de Ciencia Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile;1. School of Food and Agriculture, University of Maine, Orono, ME;2. Cooperative Extension Knox and Lincoln County, University of Maine, Waldoboro, ME;3. tComputer Information Systems, University of Maine at Augusta, Augusta, ME;1. Department of Pathophysiology, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland;2. Department and Clinic of Animal Reproduction, Sub-Department of Andrology and Biotechnology of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Sciences, Lublin, Poland;1. Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada;2. ÿcole Nationale Supérieure Agronomique de Rennes, 65 Rue de Saint-Brieuc, 35042 Rennes, France;3. Department of Population Medicine, University of Guelph, Guelph, ON N1G 2W1, Canada |
| |
| Abstract: | Seventeen Thoroughbred and Quarter Horse yearlings were used in a 2×2 factorial experiment to determine 1) whether adding fat (5% corn oil) to the concentrate would influence feed intake, growth and development and 2) whether time of hay feeding would influence energy metabolism on the basal and added fat diets. Yearlings were assigned at random, within breed and gender subgroups, to one of four diets: B-I, basal concentrate with Coastal Bermuda grass (Cynodon dactylon) hay fed immediately after the concentrate; B-D, basal with hay fed 3.5 hr after the concentrate; F-I, basal + fat with the hay fed immediately; and F-D, basal + fat with the hay fed 3.5 hr after the concentrate. The basal concentrate was formulated to meet or exceed NRC (1989) recommendations when fed with the hay. The basal + fat concentrate was formulated at 9.7% higher digestible energy than the basal concentrate and all of the other nutrients were increased proportionately so if the intake was reduced, the yearlings would still meet nutrient needs. The concentrates were fed individually to appetite for two 1.5-hr feeding periods daily in 1.5×3.0 m slip stalls. Hay was group fed in the paddocks at a rate of 1.0 kg/100 kg BW daily divided into two equal feedings. Animals were housed in four 9.1×34.9-m drylot paddocks with three, four, or five animals in each paddock. The mean age at the start of the experiment was 377±8 days. Weight and body measurements for withers height, heart girth, body length, and hip height were taken at the start of the experiment and at 28-day intervals for 84 days. Radiographs for bone mineral estimates were made at the start and completion of the experiment. During the final 28-day period of the feeding trial, three animals from each experimental group were randomly selected for a 24-h period of blood sampling to evaluate the effects of the diets on blood glucose and insulin.Fat addition to the concentrate reduced the daily concentrate DM (P=0.0187) and total feed DM (P=0.0021) intake. When feed intake was expressed as a function of BW, concentrate and total feed intakes were 1.33 and 2.14 kg/100 kg BW daily and were not influenced by diet (P>0.1). Colts consumed more concentrate DM (P=0.0039) and total feed DM (P=0.0022) than fillies. The yearlings gained an average of 0.60 kg/d for the 84 days. Weight gain, body measurements and bone mineral deposition were not influenced by gender or diet. Mean plasma glucose concentrations were higher (P=0.05) in yearlings consuming the basal concentrate with hay fed immediately than when hay feeding was delayed. When fat was fed, the time of hay feeding had no effect on plasma glucose concentrations (P>0.05). Plasma glucose and insulin were lowest just prior to the morning feeding and peaked two to three hours after both morning and afternoon feedings. Fat supplementation reduced plasma insulin (P=0.001). Results suggest that the addition of 5% corn oil to a yearling concentrate may reduce feed intake but will not reduce growth and development of the animal if other nutrients are supplied at concentrations that provide for the animal's daily needs. Delaying hay feeding may be advantageous to growing horses as it may allow the concentrate to move down the tract at a slower rate reducing the glucose peaks. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
