Slowing swine growth during market disruptions
The pandemic’s impact on livestock production, harvest and sale has been in the forefront. Processing plant bottlenecks and a decrease in consumption because of restaurant and school closures have prompted producers to re-evaluate feeding programs.
In late spring 2020, there was a need to hold pigs back from growing too quickly to allow more time at the processing plants. This was a big paradigm shift for swine producers. Usually, they are laser focused on average daily gain, feed efficiency, cost of gain and return on investment. The ripple effect of COVID-19 throughout the industry changed those objectives.
It takes approximately six months from farrow to finish to produce a hog with a final weight of 280 pounds. Kansas State University swine researchers conducted a trial that produced a pig 14 pounds lighter at the end of that period by feeding a diet reduced in amino acids. These are the building blocks for animal protein, or muscle, and critical to a pig’s growth. Lysine is an important amino acid often used in swine diets. The objective of the K-State study was to slow growth while the pigs are consuming feed ad lib (available at all times).
Four test diets were formulated to evaluate the effects of lowered lysine content on pigs’ growth:
- Diet 1 included normal amounts of lysine in the diet for the entire late finishing phase.
- Diet 2 was a “slow diet” with the normal amounts of lysine until the final two weeks of feeding. Then, the pigs were fed a corn-based diet that included only vitamins and minerals.
- Diet 3 was a “slow diet” with a 25% reduction of lysine during the entire late finishing period.
- Diet 4 was a “slow diet” with a 25% reduction of lysine until the final two weeks of feeding. The pigs were then fed a corn-based diet that included only vitamins and minerals.
Findings showed that the slow diets resulted in substantially reduced growth rate. Just by lowering the level of amino acids, the pigs were 14 pounds lighter at the end of the 44-day finishing period. When the slow corn-based diets were fed, there was an additional 12-pound decrease in body weight, resulting in a pig 26 pounds lighter.
It is important to not start the low-protein, low-amino acid diet too soon because early growth provides more muscle deposition. The reduced levels of protein amino acids work best when the pig is over 200 pounds.
By reducing amino acids, the researchers achieved their goal of slowing the growth rate of pigs with a “holding” diet while influencing feed efficiency. They were able to buy 3.5 to 4 weeks of extra time to get those pigs to market, which allowed producers to keep the animals on the farm during the packing plant slowdowns while not getting them too heavy.
When producers have to hold onto pigs that are already close to market weight, the goal is to minimize costs of keeping those animals on the farm. In the K-State study, the price of a corn-based holding diet and reduction of lysine supplementation actually lowered the cost of feed per day. Even though the trial diets resulted in poor feed efficiency, the cost was much lower without protein (amino acids) included.
Researchers said these findings could be important any time markets are disrupted, whether it’s a global pandemic or other industry challenges. These diets help protect the animal’s welfare and the producer’s bottom line while providing a safe supply of pork to the food chain.
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