The present study was conducted to investigate the effect of environmental temperature and backfat thickness (BT) on the reproductive performance of lactating sows. Sixty crossbred sows were allotted to four groups in a 2×2 factorial arrangement by environmental temperature (high temperature [HT], 27.5±1.76℃; low temperature [LT], 23.3±0.89℃) and BT (<20 mm, average 17.70 mm; ≥20 mm, average 23.20 mm) from July to August 2019. Sows in the HT group experienced a greater change in BT and a lower feed intake. Losses in body weight and BT were lower in sows with <20 mm BT than in those with ≥20 mm BT. Sows with low BT had a lower weaning-to-estrus interval than sows with high BT (5.20, 4.93 d vs. 5.87, 5.60 d, respectively). Piglet survivability was lower in the HT group (90.31%) than in the LT group (94.87%). Piglet weaning weight and average daily weight gain were greater in sows with <20 mm BT (5.75 kg and 201.46 g, respectively) than in those with ≥20 mm BT (5.49 kg and 188.41 g, respectively). Sows in the HT group had higher cortisol concentrations than those in the LT group (post-farrowing: HT 7.86 μg/mL vs. LT 6.04 μg/mL; weanling: HT 5.48 μg/mL vs. LT 4.40 μg/mL). In conclusion, environmental temperature adversely influenced sow performance and cortisol levels. Moreover, sows with low BT had a greater weaning-to-estrus interval when subjected to heat stress.

본 실험은 포유기 사료 급여 기간의 변화가 포유 모돈의 생리적 변화와 번식 능력에 미치는 영향을 조사하기 위해 수행되었다. 평균체중 256.15 ± 4.39kg의 F1 모돈(Yorkshire × Landrace) 30두를 공 시하였으며, 완전임의배치법에 따라 3처리구에 배치하였다. 각 처리구는 1) L0-5: 임신기 110일령부터 이유시까지 포유모돈 사료를 급여, 2) L0: 분만일부터 이유시까지 포유모돈 사료를 급여, 3) L0+5: 분 만 5일 후부터 이유시까지 포유모돈 사료를 급여 하였다. 포유기에는 모돈들에게 사료를 무제한 급여 하였으며, 실험결과 사료의 변화 시기는 모돈의 체중 및 등지방 두께에 유의적인 영향을 미치지 못하였 다. 사료섭취량에 있어서 분만일부터 이유시까지 포유돈 사료를 섭취한 모돈이 수치적으로 가장 높았지 만 처리구간 유의적인 차이는 나타나지 않았다. 산자수, 자돈의 체중 및 유성분에 있어서도 처리구간 차이는 발견되지 않았다. 결론적으로 분만 5일전부터 5일후 사이에 포유돈 사료로 교체하는 것은 모돈 의 번식능력 및 포유능력에는 긍정적인 영향을 미치지 않는 것으로 판단된다.

The present study investigated the effects of fermented potato protein (FPP, Lianol® ferity) during gestation and lactation on productivity of sows. A total of 50 crossbred sows (Landrace×Yorkshire) in their 3 to 5 parities were allotted to one of two treatments (n=25) including control and FPP groups. FPP tablets applied in sows in two stages. Stage one involved applying FPP daily from 3 days before farrowing to 2 days after for 5 consecutive days. The second stage also involved a 5 day period around weaning time from 3 days before to 2 days after. After farrowing, the amount of feed offered 3 times per day gradually increased from about 3.6 kg at farrowing to 8.4 kg at late lactation. During the first lactation FPP tended to increase backfat thickness (BFT) at weaning at the first (p=0.069) whereas FPP increased BFT (p<0.05) at weaning in the second lactation. There was no significant effect of FPP on body weight changes and daily feed intake of sows. Decreased weaning to estrus interval was associated with applying lianol tablet at the second lactation (p<0.05). Weight of born alive piglets, weaned piglets and total weight gain were greater in FPP group at the second lactation (p<0.05). Applying FPP tended (p=0.062) to increase insulin like growth factor-Ⅰ(IGF-I) at the weaning time in the first lactation. The effect of FPP on IGF-I was significant at the second lactation, revealing a higher concentration in blood at post farrowing and weaning time (p<0.05). This study shows the benefit of using FPP tablets in sows to increase blood IGF-I and both initial and final litter size to improve piglet weaning weights.