This study used an endocrinological approach to explain the differences between sows that have higher vs. lower preweaning mortality in a group-farrowing system. The association between sows that had 2 or more piglets die within the first 72 h postfarrowing (high risk) or sows that had 1 or no piglets die within the first 72 h postfarrowing (low risk) with changes in serum hormone concentrations was investigated. Multiparous sows (n = 63; parity 2 to 7) from 4 contemporary breeding groups, each mated within a week, were used. Sows were housed in a group-farrowing system where 8 sows farrowed in individual pens and shared a communal feeding and dunging area in each room. Reproductive performance, including total born, born alive, and stillborn per litter, individual weight of piglets at birth and weaning (at 5 wk postfarrowing), litter size at weaning, preweaning mortality of piglets, and sow BW before farrowing and after weaning, were recorded for all sows. Of these sows, 14 sows from 2 breeding groups were selected randomly for blood sampling through an indwelling ear vein catheter. A blood sample was collected daily from each sow 2 d prefarrowing through 2 d postfarrowing. Serum samples were analyzed for prolactin, oxytocin, cortisol, and urocortin concentrations using RIA. Among the 14 sows, 7 sows lost 2 or more piglets during the first 72 h after farrowing and were classified as high risk sows, and the other 7 sows lost 0 or 1 piglet during the same period and were classified as low risk sows. Catheters in 11 sows (5 high risk sows and 6 low risk sows) remained functional for the entire sampling period. Results indicate that high risk sows farrowed larger litters (live born = 13.8 ± 0.50 vs. 11.3 ± 0.48 piglets; P = 0.03) with lighter piglets (1.4 ± 0.04 vs. 1.7 ± 0.05 kg; P < 0.001) compared with low risk sows. In addition, high risk sows had greater oxytocin concentrations (0.09 vs. 0.07 ng/mL; SE = 0.02, P = 0.01), which might be associated with larger litters farrowed, compared with low risk sows. There were no differences between high risk and low risk sows (P > 0.30) in terms of serum prolactin, cortisol, or urocortin concentrations. These results suggest that litter size and birth weight of piglets played an important role in preweaning mortality of piglets and hormone concentrations in sows were not associated with piglet mortality in the group-farrowing system used.

Li, Y. Z., Phillips, C. E., Wang, L. H., Xie, X. L., Baidoo, S. K., Shurson, G. C. and Johnston, L. J. 2013. Effects of distillers' dried grains with solubles on behavior of sows kept in a group-housed system with electronic sow feeders or individual stalls. Can. J. Anim. Sci. 93: 57-66. A study was conducted to investigate the effects of diets that contained distillers' dried grains with solubles (DDGS) on stereotypic behaviors of gestating sows housed in stalls and aggression in a group-housed system. Sows were fed corn soybean-based control (CON) or treatment (DDGS) diets starting from their previous breeding cycle (40% and 20% DDGS as-fed basis during gestation and lactation, respectively). Group-housed sows were mixed in pens with an electronic sow feeder within 1 wk after mating. Behaviors of focal sows (n = 27 in stalls, n = 40 in pens) were video-recorded for a period of 24 h between 4 and 8 d after mating. Salivary cortisol levels were measured on 32 focal sows (n = 16 in stalls, n = 16 in pens) during the week before mating (week 0), 1 wk and 12 wk after mating. In pens, DDGS sows fought for longer periods (P = 0.05), tended to fight more frequently (P = 0.06), and had greater cortisol concentrations (P < 0.001) at mixing compared with CON sows. In stalls, DDGS sows spent more time resting (P = 0.02), less time performing stereotypies (P = 0.05), and had lower cortisol concentrations (P = 0.03) in week 12 compared with CON sows. These results indicate that DDGS diets may compromise the welfare of sows in pens, but improve the welfare of sows in stalls.

No methods have been published for repeated blood sampling via an ear vein in group-housed sows. Therefore, the objective of this study was to develop a minimally invasive technique for the insertion of an ear vein catheter for repeated blood sampling in group-housed peripartum sows while minimizing any impact on production performance. Thirty-three multiparous pregnant sows were used including 18 catheterized sows and 15 control sows. In a group-farrowing barn, sows (8/room) shared a communal area and farrowed in individual, free-access pens. Treatment sows were anesthetized, and 1 ear was prepared aseptically 2 to 4 d before their expected farrowing date. A sterile needle was inserted into the largest and straightest portion of the vein, and the catheter, which was medical-grade microbore tubing, was inserted through the needle at least 24 cm. The needle was withdrawn, and the catheter was fixed into position and sutured to the ear. A blunt-end probe point cannula was glued onto the distal end of the catheter, and an adaptor injection cap with male Luer lock was placed on the end. The catheter was coiled and placed in a protective purse, which was cemented directly to the skin on the back of the shoulders. The catheter was flushed with heparinized saline to ensure patency. Once sows were able to stand, an elastic bandage was wrapped around the neck and upper body of the sow to hold the protective purse and exposed catheter in position. Blood samples were collected every 24 h, and catheters were flushed with heparinized saline after each collection. Fourteen of the 18 insertions were successful, and 11 of those remained functional for 4 d or more. Differences were not observed in reproductive performance between catheterized and noncatheterized sows.

The 2009 Al len D. Leman conference proceedings book is made possib le by the generous support of IDEXX. We also thank the following sponsors: AgStar F inancia l Serv ices A lpha rma Inc . Amer ican Associat ion of Swine Veter inar ians Appl ied Biosystems Bayer Animal Heal th Boehr ingerlngleheim Vetmedica, Inc. E lanco An ima l Hea l t h Fort Dodge Animal Heal th IDEXX Invervet /Scher ing-Plough Animal Heal th Nat ional Pork Board Newsham Choice Genet ics Nova r t i s An ima l Hea l t h US , I nc . Pf izer Animal Heal th P IC P igCHAMP PRRS CAP2