Dr. John Patience has seen just about everything in his 45 years of working in animal science.
Then, along came coronavirus.
“I would never have dreamed I would be doing research on slowing down pig growth,” he told those listening to his webinar as part of the 2020 Saskatchewan Pork Symposium. It was the 19th time Patience has been a speaker at the conference, although this time it was via Zoom.
He said research that has been done over the past four decades has been on how to increase growth rate and increase feed intake.
“This is just another example of how nimble we have to be in the pig industry because thing can change on a dime,” he said. “One of the things we have learned during this experience with COVID-19 and the disruption in packing plants in the mid-west (United States) was that we always have to be alert and we always have to in a position to react and to react quickly.
“The people who were least affected by the temporary slowdown or shut down of packing plants were those people who reacted the fastest and, indeed, may have even anticipated the problem.”
Patience, who works in the Department of Animal Science & Iowa Pork Industry Center at Iowa State University in Ames, Iowa, said in late April plant capacity utilization bottomed out at 54 per cent.
“The coronavirus really got started in March and started to gain a hold on us in April. We had a lot of pigs that wanted to find a home and there was just no place to put them.”
That led to a study, a quick study, of the best way or quick ways to slow down growth in pigs.
“Do you want to reduce feed intake, or do you want to slow down growth in the pigs, or do you want to lower feed costs per day as low as possible?”
“Every producer has to answer these questions because it will define what feeding strategy you are going to apply.”
He said the objective of researchers was to develop a feed regime or regimes that would slow or stop growth and do so at the lowest possible cost, with the least impact on carcass quality and meat quality, and with no or minimal impact on the health of the pigs.
Before delving deeper into the science, researchers looked at a number of things:
*1 Barn management: “We recommend these hesitantly because if they are done to extreme they could affect the welfare of the pigs. One of them is a modest increase in the temperature in your barn. We all know if the barn temperature goes up, that feed intake in the pigs goes down. If we do this modestly, this would be one way to reduce feed intake and slow down growth.
*2 Tightening feeders: “This one I am not really a fan of at all because if we overdo it, you are going to have hungry pigs which leads to behavioural problems which can lead to social vices, fighting, tail biting and so on. Maybe tighten them a little bit, but I think we can get in trouble if we do that to extreme.”
He and his colleagues looked at nutrition.
“Well, we can feed a high fibre diet, increase the bulk of the diet or the energy intake, impair the ability of the pig to eat the feed and lower daily energy intake slowly.”
He said crude protein and amino acid levels can be lowered. He said scientists knew the use of an acidic salt and calcium chloride works on appetite.
“When we started this we were able to put together a White Paper for pork producers, but there really wasn’t very much information that was available to us to really make specific recommendations.”
That led to three experiments that were put together quickly. Patience said scientists wanted to get information out to producers as fast as possible.
There were 92 farrows and gilts in the first study. They were housed individually and weighed 72 kilograms. They were tested using with eight different diets for four weeks.
“Remember at this point, we didn’t have any data so he wanted to try an array of nutritional options,” Patience said.
In a summary of the study, the following key points were made. The results were co-written by Patience and published in May in May on nationalhogfarmer.com.
Four per cent calcium chloride diet did the best at slowing pig growth rates over 28 days (approximately seven kilograms’ body weight gain), but it tends to be a more expensive option. The net cost will be determined by the balance between higher feed cost per pound compared to lower daily feed intake.
97 per cent corn diet was successful at reducing growth rates over 28 days (approximately 13.5 body weight gain). It is the simplest and least expensive dietary option.
Increasing the NDF content of diets marginally reduced body weight gains. Fibre sources can be expensive and currently are in short supply.
“We were disappointed in it,” Patience said. “We didn’t get the benefits than we thought. You have to go to at least 20 per cent NDF to get enough of a reduction in growth rate and feed intake that we were looking for.”
The second study looked at a control diet, a 97 per cent corn diet, and two that were combinations of the two. In one, corn was used in the first half of the six-week timeframe and control in the second. The other pigs were fed in the opposite order.
At the end of the experiment, pigs fed the control diet throughout the experiment weighed 123 kilos. Pigs fed the 97 per cent corn diet weighed 109 kilos.
The final weight of the pigs fed the 97 per cent corn diet for three out of the six weeks was 118 kilos. It did not matter if they were fed the 97 per cent corn diet for the first three weeks or the last three weeks; their final weight was the same.
Patience said feeding the pigs the corn diet was about 10 cents less per day per pig than the control diet.
It was also determined that pigs on the corn diet could transition to the balanced diet when packer space became available and weight gain was needed.
In experiment No. 3, pigs started at 125 kilograms, with 900 pigs — farrows and gilts — in the test. There were 19 pigs in each pen, with the pigs harvested in three cuts. The pigs were on experimental diets for 14, 28 and 42 days.
There were six dietary treatments in the experiment. Like in the other experiments before it, calcium chloride reduced body weight by a largest amount, with the corn diet again being successful in reducing body weight.
Patience was pleased with the work of scientists and the results obtained. Using a one-to-five scale on four components, he said he would give the experiments an overall score of 19 out of 20. •
— By Cam Hutchinson
