Postprandial glucose and insulin responses to a postexercise grain meal.

Many studies have examined the effect of pre-exercise feeding on glucose and insulin responses of horses. The objective of this study was to determine whether exercise performed one hour prior to a meal would attenuate the glucose and insulin responses to a meal. Data collected from 8 mature geldings in a 2 period crossover design experiment were used to determine the postprandial glucose and insulin responses to a meal of oats offered 1 h postexercise. During each period, 4 horses received a test meal following a 14 h fast (NoEx) or a 14 h fast and exercise bout (PostEx) that consisted of 48 min walking and trotting. Blood samples were collected before and at 30 min intervals for 5 h after the meal was offered. Glucose and insulin concentrations were similar between treatments at all time points (P>0.15). Postprandial glucose and insulin concentrations increased at similar rates in both groups from 0 to 90 min. Peak glucose and insulin concentrations and area under the response curves were similar between treatment groups. Glucose:insulin was not different between treatment groups at any time point before or after the meal (P>0.17). Overall, the 48 min of light work performed 1 h before a meal did not affect glucose or insulin responses to the meal. A one hour interval after mild exercise appears to be sufficient to allow normal glucose metabolism of a grain meal.

Effect of frusemide on bodyweight loss and recovery in racing Standardbreds.

This study was conducted to compare bodyweight (bwt) loss and recovery in Standardbred horses receiving frusemide compared to controls. Thirty Standardbred horses from 7 training stables that were racing at the Red Mile in Lexington, Kentucky, during the spring 2001 pari-mutuel meeting were studied. Fourteen horses (FRU) received frusemide (250 mg/horse i.v.) 4 h prior to racing, while 16 horses (NFRU) did not received frusemide. Horses were weighed on the morning of race day, prior to warm-up, after racing and the next day. Changes in bwt were calculated as percentage increase or decrease from initial bwt. Prior to warm-up, FRU horses had a mean bwt reduction of 1.30 +/- 0.63%, (P<0.01), compared to a 0.19 +/- 0.63% increase for the NFRU horses. FRU horses had a greater (P<0.03) postrace bwt loss (3.55 +/- 0.55%) than the NFRU horses (2.71 +/- 0.66%). On the morning after racing, bwt was still below initial values by 0.90 +/- 0.55 and 1.24 +/- 0.35% for the FRU and the NFRU horses, respectively. While frusemide administration increased the postrace weight loss in racing Standardbreds, it did not affect short-term bwt recovery. Further research is required into management strategies required to allow horses to replenish fluids and electrolytes safely following strenuous exercise.