Heat stress has serious negative consequences for the swine industry by reducing feed intake and reproductive performance of sows. Based on commercial observations, heat stress during the summer reduces fertility up to 15% and increases non-productive sow days by 5 to 19 days per year. In the present study, we determined the impact of dietary betaine as a heat abatement strategy in sows. Betaine is an osmolyte and has an important role in maintaining water homeostasis and cell integrity and has been demonstrated to reduce heat stress in other species. We used a total of 649 sows that were balanced by parity (169, 153, and 327 sows representing parity 1, 2, and 3 to 6) and assigned them within parity to a 2 x 2 factorial arrangement of treatments. Factors included betaine concentration: 1) in lactation (0 or 0.2%) and 2) from weaning through early gestation (0 or 0.2%). Lactation diets were corn-soybean meal based with 10% rice bran and 6.0% wheat middlings, and formulated to contain 651 ppm of choline, 3.31 g standardized ileal digestible (SID) Lys/Mcal ME and a SID Met+Cys:Lys ratio of 0.56. Gestation diets were corn-soybean meal based with 30% wheat middlings, 15% rice bran, and formulated to contain 651 ppm choline, 1.82 g SID Lys/Mcal ME and a SID Met+Cys:Lys ratio of 0.69. Sows were started on lactation diets (with or without betaine) the day they farrowed. Sows that did not return to estrus within 14 d after weaning were removed from further study. Average room temperature was 25.2±2°C during lactation and 24.1±3°C during the weaning-to-35 d post-insemination period. Sows that received betaine during lactation had greater body losses (1.02 vs 1.18 kg/d, SEM ± 0.06, P = 0.002) due to a lower feed intake (4.29 vs. 4.14 kg/d, SEM ± 0.07, P = 0.08). No difference in litter gain (52.3 vs. 51.35 kg, SEM ± 0.6, P = 0.16) and number of pigs weaned were observed (10.95 vs. 10.90, SEM ± 0.5, P = 0.5). Feed efficiency was greater (0.327 vs. 0.284, SEM ± 0.01, P = 0.001) for sows fed diets without betaine. Feeding betaine post-weaning tended to increase (P=0.08) the number of sows returning to estrus within 14 d (0.92 vs. 0.88, SEM ±0.03) and tended to reduce wean-to-estrus interval (5.78 vs. 6.68, SEM ±0.4, P=0.06). Supplementation of betaine to mature sows post-weaning reduced farrowing rate (0.897 vs. 0.790, SEM±0.025, Interaction, P = 0.07). Feeding betaine post-weaning to parity 1 sows resulted in the greatest total number of pigs born (P < 0.08) and pigs born alive (P < 0.05). Feeding betaine during lactation to parity 4+ sows resulted in the greatest total number of pigs born (P < 0.08). Subsequent litter size was not affected in Parity 2 and 3 sows.
• Supplementation of 0.2% betaine during lactation did not improve sow and litter performance.
• Supplementation of 0.2% betaine during lactation increased litter size in sows that were parity 4 or greater.
• Supplementation of 0.2% of betaine post-weaning increased the number of sows bred and reduced the wean-to-estrus interval.
• Feeding 0.2% betaine post-weaning increased litter size in parity 1 sows.
Eric van Heugten
North Carolina State University
Raleigh, NC 27695-7621
Phone: (919) 513 1116