Early Weaned Pig Vices Studied

As weaning age decreases, pigs' behavioral vices, such as belly nosing and belly sucking, tend to increase. The lacerations and weakened immune response caused by this behavior may increase cull rates and "poor doers."

Researchers at the Prairie Swine Centre in Saskatoon, Saskatchewan, Canada set out to investigate some of the factors that contribute to the behavioral vices sometimes associated with early weaning. The research team studied the effects of genetic lines, diet form and various types of pen enrichment in the incidence of belly nosing and sucking behaviors in 7-day-old piglets.

Behavioral vices were studied in 291 piglets, weaned at 7 days of age and housed in 19 pens. Piglets were fed liquid diets for either seven or 14 days, then switched to dry, pelleted feed. Pen environment was modified by providing an air-filled inner tube, rubber nipples in the feed trough, or neither, which served as controls.

Pens were segregated by sex, but they contained both Duroc and Yorkshire piglets. Pigs were observed between 8:30 a.m. and 4:30 p.m. on two consecutive days when pigs were 10- to 23-days postweaning.

Live observations were made at five-minute intervals to record the number of pigs that were belly nosing, belly sucking, or nosing and sucking on other parts of penmates' bodies.

Researchers found Yorkshires engaged in more belly sucking than Durocs (4% versus 1.6%) and in belly directed behavior (9.2% versus 6.2%, respectively).

The rubber nipples, for example, reduced the percentage of time spent belly sucking (1.1%) compared to the inner tube (3.1%) while 4.1% of control treatment pigs displayed the vice. Nipples also reduced the total amount of sucking observed (1.6%) compared to the inner tube-treated pigs (3.5%) and controls (4.8%).

The length of liquid diet supplementation (seven or 14 days) was not related to belly nosing behavior, researchers say.

In general, nipples reduced the level of sucking and belly-directed behaviors in the Yorkshires but not the Durocs. Overall, environmental treatments intended to reduce such behaviors may not be effective, they conclude.

Researchers: Clover Bench, Stephanie Hayne, Clarence Froese and Harold Gonyou, Prairie Swine Centre Inc., Saskatoon, Saskatchewan, Canada. Phone Bench at (306) 373-9922 or e-mail bench@sask.usask.ca.

Group Size Impacts Wean-Finish Performance

Researchers at the University of Illinois, in collaboration with United Feeds Inc., evaluated the effect of group size on pig growth and carcass performance in a wean-to-finish facility.

A total of 1,400 pigs were allocated to test group sizes of 25, 50 and 100 pigs/pen. Pigs were placed on test at weaning (averaging 17 days old and 13 lb.) and were marketed averaging 255 lb. Feeder trough space was standardized at three holes/25 pigs; floor-area allowance was the same for all group sizes, 7.3 sq. ft./pig.

Researchers found that during the first eight weeks of the test, pigs in groups of 50 and 100 had 3% lower average daily gain (ADG) and feed efficiency (feed:gain) compared to 25-pig groups. Average daily feed intake (ADFI) was similar in all groups during the period.

During the finishing period, however, the growth performance of the 50- and 100-pig groups was similar to the 25-pig groups; therefore, ADG, feed:gain and ADFI were similar for the overall weaning-to-market period.

Mortality rates and pig-weight variation within a pen was similar for all groups at the end of the study. Likewise, group size did not affect backfat thickness, loin eye depth or carcass dressing percent.

These results support recent studies conducted by these researchers that found pigs fed in large groups of 100 had 7% lower growth performance when compared to groups of 20 pigs housed in a conventional, nine-week nursery facility. However, results of this experiment indicate that wean-to-finish facilities may be stocked in groups of 25 to 100 without adversely affecting overall performance or carcass measurements. Researchers point out the larger group sizes reduce gating and feeder costs.

Researchers: Bradley Wolter, Mike Ellis, Stanley Curtis, Dan Hamilton and Nathan Augspurger, University of Illinois, and, Doug Webel and Eric Parr, United Feeds Inc. Phone Wolter at (217) 333-0794 or e-mail b-wolter @students.uiuc.edu.

Sow-Litter Impact on Ground Cover

Sustainable pork production systems have attracted the attention of researchers at Texas Tech University.

In an effort to better understand the management required to preserve ground cover on farrowing paddocks, researchers studied two 12-acre radials (Radials 1 & 6), each with 12 one-acre paddocks stocked in rotation with 40 to 60 PIC sows. Nose rings were not used to discourage rooting.

The two sites, formerly enrolled in the U.S. Department of Agriculture Conservation Reserve Program, were established with Old World Blue Stem grasses.

Researchers collected ground cover estimates - percent grass and weeds, respectively - when the study began in October 1998. Lactating sows were placed in Radial 1 in January 1999. In July 1999, 7,200 lb. of forage was harvested from Radial 1 (stocked) and 14,000 lb. was harvested from Radial 6 (unstocked). In August, an inch of water was irrigated onto Radial 6.

At the end of 13 months (February 2000), all sows were moved from Radial 1 to Radial 6. In June 2000, estimates of grass and weeds were again collected.

At the start of the 18-month project, ground cover on the 24-acre site was estimated at 87%.

At the conclusion, ground cover actually improved to an estimated 89.8%, indicating overall stocking density and animal nutrient deposition resulted in a small but significant improvement in ground cover. And weed content actually decreased.

On average, a paddock was used for four weeks stocked with six sows and their litters, then rested for three weeks before restocking.

Weaning averages ranged from 7 to 9 pigs/litter during the study.

It is important to recognize that the pasture containing sows and piglets for 13 months (Radial 1) had less improvement in pasture condition than did Radial 6, which was stocked for just four months.

Researchers cited four inputs that helped improve pasture conditions, and they are noted with corresponding letters (a,b,c) in Table 11:

- Application of organic or inorganic fertilizer;

- Harvesting forage to allow for re-growth; and

- Rain or application of water to foster plant growth.

Clearly, the pigs both harvest (sometimes in a damaging way) and fertilize the grass, researchers observed. And, pastures containing predominantly Old World Blue Stem could be stocked with up to 2.5 sows/acre with minimal or even positive environmental impact. Of course, their ability to control water application, using irrigation, was a factor.

Finally, researchers acknowledged that additional study would determine soil nutrient flows (nitrogen, phosphorus, potassium, calcium) to assure a sound environmental balance. Soil sampling on the site indicated there was no nitrogen accumulation when the ground cover was maintained.

Researchers: John J. McGlone and Harold Rachuonyo, Texas Tech University; phone Rachuonyo (806) 742-2826 or e-mail harry.rachuonyo @ttacs.ttu.edu.