How to slow finishing pigs’ growth rate

How to slow finishing pigs’ growth rate
Apr 22, 2020

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Producers can consider implementing some alternative feed programs in the short term

by Andrea Gal
Farms.com

As processing plant closures across the Midwest due to COVID-19 have created a backlog of pigs on farms, American producers are exploring options to slow the growth rate and feed intake of finishing pigs. And scientists at Iowa State University’s Iowa Pork Industry Center are stepping up to help.

Dr. Laura Greiner, an assistant professor in the department of animal science at the university, emphasized that pork producers must work closely with their nutritionists, veterinarians and ventilation experts as they develop, implement and continue to reassess their plans. However, together with Dr. John Patience, a professor in the university’s department of animal science, Greiner outlined some practical strategies farmers can consider during these difficult times.

The goal is to try “to maintain these pigs at a certain weight or slow the rate of gain without significantly increasing the cost,” she said during a webinar last night. At the same time, producers must “ensure diets meet all nutritional requirements” for pigs, she added.

Greiner and Patience outlined five possible strategies.

  1. Low-energy high-fiber diet

Perhaps the easiest strategy to implement is a low-energy high-fiber diet. Ideally, the neutral detergent fiber (NDF) should be 20 per cent or higher.

Fiber options include wheat midds, corn germ meal or soy hulls. Distillers dried grains might not be available due to the closure of some ethanol plants, Patience noted.

“We might need to be a bit creative in our discussion of what we can use on-farm or locally,” Greiner added.

Producers should be mindful of the risk of mycotoxins in these fibrous ingredients, Patience said. This type of diet will also affect carcass yield by about 1 percentage point.

  1. Low-protein, low-amino acid diet

In the past, when producers faced tight budgets, researchers discussed the option of a low-protein, low-amino acid diet. This strategy might be helpful under current circumstances, too.

Likely, if employing this strategy, producers and their nutritionists should decrease amino acids such as SID lysine in the feed program by about a quarter or even a third.

But, when designing this diet (as with all the other options), producers and feed experts must ensure that nutrients like calcium, phosphorus and potassium continue to be incorporated into feed programs at sufficient levels.

  1. Use of calcium chloride

The addition of a salt called anhydrous calcium chloride to a diet will lead pigs to reduce their feed intake. The calcium chloride should account for “somewhere between 3 and 4 per cent of the diet,” Patience said.

But, “in order to maintain our calcium-to-phosphorus ratio, we need to add more phosphorus” to the feed, he added.

Producers must ensure pigs on this diet always have access to good-quality drinking water.

Farmers should also only use this diet for about three to four weeks in the post-marketing period, as researchers “don’t have enough data to recommend using” the diet for longer, Patience said.

  1. Restricting access to feed

Depending on the type of feeders producers have in their barns, another strategy could be tightening the feeders a bit. Farmers can consider about a 10 to 20 per cent coverage of the trough, Patience said.

But it’s important to monitor the behavior of the pigs for the development of vices like tail-biting. Increased competition over feed can also increase the variability of growth within the herd, as the more dominant pigs “will get the feed they want,” Patience added.

  1. Elevated barn temperatures

Assuming a comfortable humidity level in the barn, “for every 2 F (1.1 C) the temperature rises above the comfort zone,” the pig’s feed intake will decrease by about 0.1 pound (0.05 kilograms) per day, Patience said. A higher humidity further decreases feed intake.

But producers must be very careful if they opt to try this strategy, as “we don’t want to create too much stress on our animals,” Patience said.

Overall, Patience emphasized the importance of having a plan to ensure producers are prepared for a range of possible scenarios.

Dr. Nick Gabler, a professor in the department of animal science at Iowa State University, and some of his graduate students started a trial in mid-March to examine the results from the application of these strategies. Preliminary research findings are available here.

To learn more about the strategies outlined by Greiner and Patience, read this article.

National Pork Board and the Pork Checkoff, Des Moines, Iowa photo

 

 

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