Today's modern sows walk a very fine line in trying to live full, productive lives. They are leaner throughout their productive parities. Gilts are often younger and leaner when they are bred.
Lean genetics are what the industry wants. But when lean finishers become replacement gilts, their low backfat levels (averaging 0.48 to 0.56 in.) don't provide much margin for error as productive breeding animals, points out Ross Kiehne, DVM, Swine Vet Center (SVC), St. Peter, MN.
At SVC, the goal is to keep sows in condition and a productive part of the herd beyond three parities, to maximize output.
To accomplish that goal, the clinic has developed a program of body-condition scoring and herd profiling. The program points out inadequacies such as poor feeding regimes, or lack of attention to sows, which the producer can work to correct.
By using the profiling program to correct those inadequacies, sows will live longer, be more productive and more efficient. Then, they will also be in more uniform condition at farrowing, which will help to maximize lactation intake, he says. Sows will also enjoy improved welfare.
The end result is better parity structure and lower culling and mortality rates, Kiehne reports.
Measuring sow backfat doesn't correlate directly to changes in sow productivity, he admits. However, sow condition and backfat can provide an indicator of how long the animal remains productive.
For the on-farm backfat scanning/profiling program, the clinic selects four groups with 30 animals per group. Groups include gilts just bred, weaned sows, animals 50 days bred and animals just prior to farrowing. Parity distribution is important to give a good picture of the herd's condition, asserts Kiehne.
The females' backfat is measured using a RENCO ultrasonic backfat scanner.
Backfat readings for the four groups are averaged. Backfat should increase through gestation and herd variation should narrow.
Sow backfat targets from SVC are:
0.64 to 0.72 in. (16-18 mm.), at breeding, for the gilt;
0.6 in. (15 mm.) at weaning;
0.64 to 0.68 in. (16-17 mm.) at mid-gestation, and
0.72 to 0.76 in. (18-19 mm.) just prior to farrowing.
Ultrasound scanning helps understand the relationship of sow conditioning to backfat as follows:
Backfat measurements draw attention to the importance of sow conditioning;
Backfat readings help train the producers' eyes as to what is too thin or too fat;
Provides an objective score of body condition;
Provides herd profiling for backfat. Performed quarterly, it helps track production and reveals variation and reasons for culling, and
Results can be used to gauge herd performance and make precise feeding recommendations.
A second method to guide conditioning is to tag gilts at breeding with a special tag. These gilts are followed throughout their lifetime. Backfat measurements are taken every 30-60 days and compared to reproductive performance. Results to date indicate thinner animals did poorly in lactation, had a longer wean-to-estrus interval and had a higher culling rate. The backfat levels didn't have an effect on born alive or farrowing rate.
Feeding for Condition
To help sow condition and make sow feeding easier, Kiehne says to start by routinely checking sow condition when doing chores.
But don't check sow condition too often. “The producer must give the feeding program an opportunity to work to make a change in the sow's condition,” he states.
“A good program is to give the sow full feed from weaning to breeding, then check and adjust the amount fed after breeding, at 30-day pregnancy check, at 50-day pregnancy check, a 70-day visual check and increase the feed at 90 days of pregnancy,” Kiehne advises.
Also, to simplify feeding for conditioning, establish a baseline amount of feed for a properly conditioned animal, he continues. Then consider that an over-conditioned animal needs 1 lb. under that baseline and thin sows need 2-3 lb. over the baseline or more.
“If a very thin animal exists, they need to be given the opportunity to eat as much as they can, to get them back into proper condition quickly,” Kiehne stresses. Grouping these animals close together or in a pen can help.
“It has been our experience that putting condition on an animal is much easier than taking it off,” he notes. “It can often take a couple of parities to get an over-conditioned animal back down to the proper condition.”