The research, partially funded by the Indiana Pork Producers and the National Pork Producers councils, was reported this summer in the national council's 1996 Research Investment Report.
"If a producer's hogs are already healthy and not vitamin A deficient, a single shot of the vitamin per hog isn't going to do anything for them," said Purdue animal scientist Mark Diekman. "Especially if a hog already produces pretty good-sized litters, an injection of vitamin A probably won't bring any improvement. It largely depends on the genetics of the pig."
Diekman and Purdue animal scientist Wayne Singleton gave each of 977 sows a single injection of 1,000,000 International Units of vitamin A, then monitored the size and weight of their litters. The researchers gave the injection at different points in a sow's life, from weaning until 110 days after she'd been bred.
Timing didn't matter. When compared to a control group of pigs that received placebos, there was no difference in total litter size or weight, no matter when a sow was given the shot of vitamin A. Also, a single injection did not increase the chances that piglets would live after birth, nor did it decrease the number of runts born per litter.
Other researchers had found that litter size increased when they gave vitamin A, but the hogs they tested were already deficient in the vitamin, Diekman said. Another group found that litter size increased when hogs received a series of vitamin A shots. The Purdue researchers were the first to test single vitamin A shots and to show no effect.
CONTACT: Diekman (765) 494-4829;
e-mail, mdiekman@ansc.purdue.edu
ACS code/970822 Ag Diekman.vitaminA/9708f35
Writer: Rebecca Goetz (7650 494-0461,
e-mail
rjg@aes.purdue.edu