Effectiveness of a pair-gain feeding strategy for individually fed, group-housed finishing pigs.

Crossbred barrows (n = 48) and gilts (n = 12) were used to examine the effectiveness of a pair-gain feeding strategy for individually fed, group-housed barrows. In a pair-gain feeding strategy, barrows were individually restricted to a feeding level at which their growth was similar to the mean growth of gilts with ad libitum access to feed. The purposes of this feeding strategy were to have barrows and gilts reach slaughter weight at the same time and to improve carcass traits of the barrows. At 29.8 +/- .4 kg BW, barrows were assigned to either the pair-gain or the ad libitum treatment. All pigs had free access to feed until they reached 60 kg BW. The experimental period was from 60 to 110 kg BW. The 12 group-fed gilts and 24 individually fed barrows (12 per pen) were also given free access to feed throughout the experimental period. The remaining 24 barrows (12 per pen) were put on a pair-gain feeding strategy. In the pair-gain feeding strategy, the weekly feed allowance of each barrow was based on its measured BW and computed energy conversion ratio and on the mean growth of the gilts. The barrows in the pair-gain treatment grew at the same rate as gilts. The ad libitum intake barrows grew faster (P < .05) and had a poorer energy conversion ratio for production than the barrows in the pair-gain treatment. The total energy conversion ratio, backfat thickness, and lean meat percentage were similar (P > .10) for the two treatments. In conclusion, the pair-gain feeding strategy was effective in achieving similar growth between barrows and gilts. The total energy conversion ratio and carcass traits of the barrows, however, were not improved.

Electronic identification with injectable transponders in pig production: results of a field trail on commercial farms and slaughterhouses concerning injectability and retrievability.

A nationwide electronic system for the identification of all pigs is a means to achieve a tighter control of livestock and meat in the Netherlands. In order to examine the use of electronic identification transponders, two field trails were performed. Transponders supplied by three separate companies were tested on pigs on commercial farms. In phase 1, each device was examined on separate farms and in phase 2, the three devices were tested on each farm. A total of 3,436 and 5,947 transponders from the different suppliers were injected in the base of the ear at weaning in phase 1 and 2 on seven and five farms, respectively. The following aspects were examined: technical labour for injection and reading, readability of the transponders, impact on tissues at the injection site, and retrieval of the transponder after slaughter. After instruction the farmer was well able to inject a transponder in a restrained piglet. The results show that in phases 1 and 2 1.6% to 7.3% of the transponders were unreadable at retrieval in the slaughter line, which is significantly (p < 0.05) higher than the required maximum loss of 1%. The 1.6% failure rate in phase 1 involved transponders from a single supplier. Loss of identification was associated with rejection after injection, expulsion during inflammation and technical failure. Three weeks after injection on average 0.6% of the piglets had an observable inflammation and at the time of retrieval pus was found around, on average, 1.2% of the transponders. An average of between 37% and 88% of the transponders were retrieved in the slaughter line from the base of the ear in phases 1 and 2. The other transponders were retrieved medial or caudal to this position. This positional variation meant that it was not consistently possible to remove the transponder from the carcass within the required 4 second time period. It was concluded that the systems should be improved before recommending their introduction on a large scale, because the variation in readability and location is too high.