Q. How early in lactation is milk production set?
The first 48 hours post farrowing will generally establish the milk production and mammary-secretory capability of the sow. Unused glands will become nonfunctional within a few days post farrowing. This is the major reason for performing cross-fostering of pigs early in lactation.
Q. How can sow lactation feed intake be determined?
One way is to weigh out a certain quantity of feed (e.g., 100 lb.) for each sow and then determine how many days that quantity of feed will last. Divide the amount of feed used by the number of days to establish daily feed intake. An alterative method is to record the number of feed containers (weigh scoops, coffee cans, etc.) used to feed the sows over a period of several days and determine the average amount consumed per day. Because sows differ in their ability to adjust to feed post farrowing, it may be best to determine feed consumption after four or five days post farrowing.
Q. Is it necessary to adjust the dietary lysine level in my sow herd when I am getting low feed intakes?
Yes. Lysine is generally the amino acid most likely to limit milk production in the lactating sow when a corn-soybean meal diet is fed. A low feed intake will result in a low lysine intake. It is essential to formulate lactation diets to a lysine concentration that reflects the feed intake of the sow herd. This process is important for first-parity sows and during the hot months of the year when feed intake is low.
Q. Is there a benefit in feeding higher dietary protein/lysine during lactation to my parity-one sows?
Yes. Large lactation weight losses and low feed intakes followed by poor rebreeding performance are common occurrences, particularly with first-litter sows. A limited amount of research suggests that the feeding of a lactation diet with a lysine level above 1.00% may be beneficial in eliminating some of these adverse effects in first-parity sows.
Q. How much lysine is required for the lactating sow?
Sows weaning eight pigs or less require from 35 to 40 grams of lysine per day, whereas those sows that wean 10 pigs or more may require 50 grams per day.
Q. Is there any value in adding valine to lactating-sow diets?
No. Some experiments have demonstrated a response to added synthetic valine (essential amino acid) to sow diets but most have not. When synthetic lysine is used in the lactation diet and replaces soybean meal, the concentration of other amino acids (e.g., valine) may be reduced below the sow's requirement. In contrast, if soybean meal is used as the sole supplemental protein source, there will be no benefit to added valine.
Q. How much supplemental fat should I add to my gestation and lactation diets?
Adding fat to sow diets at a moderate level (3 to 5%) has not affected sow lactation feed intake, nor has it been shown to affect sow lactation weight loss. Levels of 8 to 10% added fat have resulted in reduced sow-feed intakes. The addition of 3 to 5% fat to the lactation diet has, however, been shown to increase milk-fat content and will generally result in larger litter weaning weights. When fat is added at dietary levels above 5%, the bridging of feed in the sow feeder may become a problem. Generally, supplemental fat is not recommended during gestation unless it is fed to thin sows during the latter portion of pregnancy.
Q. My sows appear constipated during late gestation and the first few days post farrowing. Is this normal? How should I prevent this?
Dehydration is common following the farrowing process because the sow has lost body water from the expulsion of birth products. It takes a few days for a sow to recover from the farrowing process and to return to a normal water balance. In general, if a sow consumes an adequate quantity of water and feed during the first few days post farrowing, the remaining portion of the lactation period is considered to be relatively safe from constipation problems. If constipation persists, laxatives or a diet containing a higher fiber level (e.g., wheat bran) can be fed during late gestation and early lactation.
Q. Can a sow that has just weaned her litter be used as a foster mother for lightweight pigs?
Yes. Under proper management conditions and assuming the nurse sow has adequate body condition to nurse for an additional few days, the sow has successfully nursed the adopted litter. This procedure can be effective when pigs are batch weaned, but not when the all-in, all-out weaning practice is followed. Care should be taken to ensure that the transfer of pigs is successful. Allow the milk supply to build up in the sow's mammary glands for a few hours and then permit the sow to nurse the litter immediately upon transfer. This will result in a more successful transition.
Q. Is split-weaning helpful?
Under conditions where you want the lighterweight pigs to be heavier at weaning, the removal of the heavier pigs (allowing the lightweight pigs to remain nursing the sow) will give good results. Lightweight pigs will benefit from a few extra days of nursing the sow. If the sow nurses at least five pigs, she will not come into estrus while nursing.