278 Phytogenic feed additive increased sow lactation average daily feed intake, litter weaning weight, and subsequent conception rate when fed in summer environmental conditions

Abstract

Abstract An experiment was conducted to test the hypothesis that feeding a phytogenic feed additive (Fresta F, Delacon, Austria) to sows during lactation would increase lactation average daily feed intake (ADFI) during natural heat stress from summer environmental conditions. At the time of entry to lactation facilities, 192 sows were randomly allotted by parity and within farrowing batch to one of two treatments. A basal lactation diet based primarily on corn, soybean meal, and dried distiller’s grains with solubles (DDGS) served as the control treatment, whereas the test treatment contained 0.04% phytogenic feed additive at the expense of corn. Before farrowing, sows were limit fed, but once farrowing occurred, sows were provided with ad libitum access to feed. Individual feed disappearance was recorded daily, and sow was considered the experimental unit. Sow body weights (BW) and ultrasound backfat thickness were recorded at the time of entry to and exit from the lactation facilities. Litter weights were recorded at birth and at weaning, and litter inventories were recorded at birth, upon completion of cross-fostering within treatment, on d 5 of lactation, and at weaning. Ultimately, 185 sows completed the study and were included in statistical analyses. Data were analyzed using the lme4 package of R 4.1.2, and the statistical models included the fixed effect of treatment and the random effects of parity and farrowing batch. Data were assumed to be normally distributed, except for pig survival and conception rate, which were analyzed using generalized linear mixed models specifying a binomial distribution. Total and live litter size did not differ at birth, nor did litter birth weight (Table 1). Inclusion of the phytogenic feed additive increased (P < 0.05; ADFI in lactation from 6.21 to 6.74 kg per day. In turn, the phytogenic feed additive tended (P < 0.10) to increase litter wean weight, which was driven by numerically increased piglet survival (87.47% for control and 89.37% for phytogenic, P = 0.126) and a tendency (P < 0.10) for increased average pig weaning weight. Sow BW did not differ at entry to lactation, though sow weight at weaning tended to be greater (P < 0.10) when the phytogenic feed additive was fed. The phytogenic feed additive also increased (P < 0.05) subsequent conception rate from 88.7 to 97.8%. In conclusion, feeding a phytogenic feed additive during summer conditions increased lactation feed intake, which resulted in increased weaning weight and improved subsequent conception rate.