sealPurdue Ag News Briefs

September 1997

Purdue study: One vitamin A shot does nothing for hogs

WEST LAFAYETTE, Ind. -- Hog farmers who hope to boost pig production by giving each of their healthy sows a single, massive shot of vitamin A are probably wasting their money, according to Purdue University research.

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,

With all-in/all-out, hog producers may not need antibiotics

WEST LAFAYETTE, Ind. -- Many hog producers use antibiotics to help keep hogs healthy. In some situations, antibiotics are warranted. However, a Purdue University study suggests that hogs raised in all-in/all-out (AI/AO) management systems live in such a disease-free environment that antibiotics could well be a waste of money for the producer.

In an all-in/all-out system, animals of similar age enter and leave a farrowing or nursery unit at the same time.

Purdue animal scientist Mark Diekman and animal sciences graduate student Amy Ice raised 200 barrows in AI/AO and 200 barrows in continuous management systems. Half of each group received antibiotic treatment, the other half did not.

At the end of six months, hogs in the AI/AO group had fewer lung lesions and produced more lean meat than did the hogs in the continuous management system. However, the AI/AO group that was given antibiotics did no better than did the untreated AI/AO group. The researchers' results suggest that for hogs raised in AI/AO management systems, routine use of antibiotics could be a waste of money.

Diekman reported his work last month at the national meeting of the American Society of Animal Science.

CONTACT: Diekman (765) 494-4829; e-mail,

Researcher aims to get better-tasting pork from lean hogs

WEST LAFAYETTE, Ind. -- If the trend toward leaner pork continues, the meat's taste and tenderness could suffer, says Purdue University animal scientist Allan Schinckel. To prevent the problem, Schinckel is figuring out how hogs deposit fat in their muscles. He reported his work last month at the national meeting of the American Society of Animal Science.

"The swine industry does not have a serious problem, yet," Schinckel says. "However, if payment and selection for extreme leanness continues, the percent of intramuscular fat will decline to the point that the pork will become much drier and tougher, especially when overcooked."

As he has searched for ways keep lean pork tender and juicy, Schinckel has studied fat deposition in genetic lines of average-lean and very lean pigs. He fed low-fat diets to half of the pigs from each group, high-fat diets to the other half. The average-lean pigs on high-fat diets deposited more fat in their muscles, and meat from them was more marbled. Very lean pigs, on the other hand, did not deposit more intramuscular fat -- no matter how much fat they were fed.

Contact: Schinckel, (765) 494-4836; e-mail,

Just how content is that cow?

WEST LAFAYETTE, Ind. -- At Purdue University, Julie Morrow-Tesch is developing video-based guides that will help students, producers and researchers figure out how content their animals are. Morrow-Tesch reported her work in July at the national meeting of the American Society of Animal Science.

Livestock producers want their animals to be content and at ease, not just because it's humane, but because contented, unstressed animals are better meat producers. But it's not always easy to tell if an animal is happy, says Morrow-Tesch, an animal scientist with the Agricultural Research Service.

Traditionally, researchers and producers have tried to determine an animal's level of contentment by observing and describing animal behavior. However, two people watching one cow or hog may rate the animal's behavior very differently. Just as field guides help bird watchers identify birds, Morrow-Tesch's video-based guides will help researchers identify animal behaviors and standardize their contentment ratings.

The video guide also will be useful for professors teaching animal behavior courses. Researchers trying to rate an animal's behavior will compare it to video clips in the guide, or they will videotape an animal and feed the video into Morrow-Tesch's video-based computer guide. The computer guide will automatically track, analyze and rate animal activity on the video clips.

Morrow-Tesch says the video guide is now private and used only for research, but she plans to make it available within six months to anyone who has access to the Internet.

Contact: Morrow-Tesch, (765) 494-8022; e-mail,

Researcher figures out how tannins block nutrition

WEST LAFAYETTE, Ind. -- Purdue University animal scientist Layi Adeola has figured out why livestock have trouble gaining weight on a diet of tannin-rich sorghum. His work, reported in July at the national meeting of the American Society of Animal Science, eventually may help livestock, and people, get more nutrition out of lower-cost, tannin-rich grains.

People in Africa and Southeast Asia depend on sorghum as a staple in their diets. Producers in the southern and central United States use it for livestock feed. It's available and fairly cheap, but not as nutritious as tannin-free grains.

"With a high-tannin diet, there can be as much as a 20 percent to 50 percent decrease in weight gain," Adeola says.

When Adeola investigated the problem, he found that tannins attach themselves to certain digestive enzymes bound to the membrane of the small intestine. Unfettered, the enzymes snag passing proteins and carbohydrates, break them down into amino acids and sugars, and make them available to go into the animal's bloodstream. When bound to tannins, however, the enzymes are unable to catch and break down passing food molecules. Potential nutrition passes through instead of being absorbed.

Adeola would like to foil the tannins. "Right now, any remedy is still speculative," he says. "But when we understand the whole picture, we may be able to look for agents that could reverse or decouple the binding between tannins and enzymes."

Contact: Adeola, (765) 494-4848; e-mail,

Compiled by Chris Sigurdson, (765) 494-8415; e-mail,
Purdue News Service: (765) 494-2096; e-mail,

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