Bernie Peet is president of Pork Chain Consulting Ltd. of Lacombe, Alberta, and editor of Western Hog Journal. His columns will run every second week in the Manitoba Co-operator.
The swine research team at Kansas State University, under the leadership of Dr. Mike Tokach, has an enviable reputation for carrying out practical and relevant research. The proceedings from its annual swine day provide a valuable reference – I have selected a handful of topics from the 2009 event and encourage you to visit the KSU website to see others.
FEEDING SOWS IN LATE GESTATION
It is widely accepted that increasing feed level in late gestation (day 90+) results in less body fat loss in the sow during the last part of gestation and in the lactation period. A KSU trial looked at the effect of increasing feed intake by two lbs./0.9 kg during this period on both gilts and sows over two parities. As might be expected, both gilts and sows fed the additional feed were heavier and had higher backfat at farrowing. During the lactation period gilts fed the higher amount lost more weight and backfat than those fed the basal diet. However, sows showed little difference in weight or backfat loss in lactation. Average lactation feed intake for gilts was significantly lower if they had received extra gestation feed (10 lbs./4.5 kg/day versus 11.7 lbs./5.3 kg/ day) whereas sows actually ate slightly more during lactation when they were fed more in late gestation. Increasing feed level in late gestation led to higher birth weight in gilt litters but lower birth weight in sows’ litters. Also, gilts fed the higher level of feed had a higher conception rate after weaning, but in sows it was lower. Subsequently, the parity two sows (previously gilts) that received additional feed in late gestation had increased average piglet birth and weaning weight during the subsequent lactation period. The researchers concluded that there is no benefit to increasing feed level in late gestation for sows and it incurred an increase in feed costs of $3.50 to $5 per sow.
FEEDING MEAL OR PELLETS
Two trials were carried out to compare feeding finishing pigs with a diet in meal or pellet form, with all other factors identical.
Pigs fed pelleted feed had a higher daily gain (925 versus. 871 g/d), although there was little difference in feed intake. Feed efficiency was 5.3 per cent better in pellet-fed pigs (2.68 versus 2.83) and these pigs were over six kg heavier at the end of the 112-day trial. In a second trial, these differences were not as pronounced, but it was noted that the pelleted diet used had a much higher percentage of fines than in the first trial. Pigs fed pellets had heavier carcasses and higher carcass yield, although there was a slight tendency towards lower loin depth and carcass lean percentage.
This trial mirrored the results of other research which suggests a five per cent benefit in feed efficiency of feeding pellets rather than meal. However, it also highlights the importance of pellet quality and percentage fines. If pellet quality is not good, the additional cost of pelleting a diet may not be recovered. Also, pigs tend to root out pellets from the feeder and in the process discard the fines, leading to more wastage.
THINNING OUT FINISHING PENS
It is common practice to remove a few larger pigs from finishing pens a week or two before the majority go for slaughter, but what effect does this have on the remaining pigs? Two KSU trials looked at (1) removing one, two or four pigs from a group of 25 at 15 days prior to marketing the rest and (2) removing two pigs per pen from a group of 27 at 20 days prior to shipping, then zero, two, four, or six pigs per pen 10 days before marketing the group.
Clearly, removal of pigs results in more pen space for the remaining pigs and improved feed and water access. As a result, in both trials, where pigs were removed from a pen, the remaining pigs had a higher feed intake, improved growth and better feed efficiency. This effect was larger as the number of pigs removed increased. The trial report concluded that income over feed cost was best when two pigs were removed at one time. Improvements in performance from removing more than two pigs were not great enough to overcome the total reduction in total weight produced by the pen.
ABSCESSES AND NEEDLE-FREE INJECTIONS
Given the trend towards needle-free injection, notably in Manitoba, I was interested in a trial comparing this method with the conventional needle and syringe technique, especially in regard to the number of abscesses four weeks after treatment.
Nursery-age pigs received four injections of aluminum hydroxide adjuvant, one in the neck and one in the ham by needle-free jet injection on one side and injection in the same places on the other side using a conventional needle and syringe. Immediately prior to injection, the external surface of the injection sites was contaminated with the bacteria Arcanobacterium pyogenes, which is commonly associated with abscesses in pigs.
After 28 days, pigs were euthanized and post-mortems carried out. Twelve abscesses were found at needle-free injection sites, whereas only one abscess was found where a conventional needle injection method was used. The researchers concluded that the implementation of needle-free jet injection systems in market-hog production will be beneficial by eliminating the potential for needles and needle fragments in meat products, but it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork-processing plants.