The deleterious effects of heat stress during the summer months on pig performance and welfare are one of the biggest concerns that swine producers worldwide face every year (Castro Junior & Silva, 2021). Sow farms are no different: as Silva et al. (2021) highlight, when environmental temperatures exceed the sow’s ideal comfort zone (18 to 20ºC), a range of physiological and behavioral responses are triggered to increase heat loss, while decreasing heat production caused by sow metabolism. Likewise, heat stress also has a huge economic impact (Guo et al., 2018). St-Pierre et al. (2003) estimate that sows suffering from heat stress can bring economic losses of over $113 million per year in the US alone. It is therefore extremely important to understand the effects of heat stress on sow performance and what alternatives we have to mitigate those effects.
The negative impact of heat stress on sows and their litters has been discussed extensively over the past few decades. Undoubtedly, one of the most critical consequences of exposure to high environmental temperatures is a drastic reduction in sow feed intake (Lucy & Safranski, 2017). Silva et al. (2021), for example, evaluated feed intake and feeding behavior of 60 mixed parity sows exposed to hot and cool seasons. Results from that study showed that feed intake is highly affected by environmental temperature (P < 0.001); demonstrated by sows having an average feed intake of 5.66 kg/day during the hot season and 7.23 kg/day in the cool season. As well, sows presented lower daily ingestion time (P < 0.01) during the hot season and lower ingestion time per meal (P < 0.05) when compared to the cool season.
Considering this, sow herds suffer several negative consequences due to heat stress and a drop in feed intake throughout their entire production cycle. As Lucy & Safranski (2017) point out, heat stress can contribute to seasonal infertility and reproductive disorders, including ovarian malfunction, delayed puberty, increased embryo mortality, long weaning to estrus intervals, low farrowing rates, and depressed litter size. Moreover, the reduced voluntary feed intake as a natural response to decrease body heat production can also result in reduced milk production (Renaudeau et al., 2005), negatively affecting offspring performance.
To improve sow performance under heat stress conditions, many research trials have been conducted to identify environmental and nutritional alternatives that can attenuate its effects. Among the nutritional solutions, feed additives such as feed flavors appear to be a very effective approach to improving the sows’ voluntary feed intake (Renaudeau et al., 2008). Feed flavors are designed to stimulate pig appetite and feed intake, especially in times of stress or when nutritional demand is high. For sows, feed flavors offer the opportunity to maximize the sows’ voluntary feed intake and consequently maximize milk production and decrease body mobilization during lactation (Silva et al., 2021).
Silva et al. (2017) evaluated the impact of supplementation of different levels of feed flavor (Krave AP-P, Adisseo) during lactation of three hundred mixed parity sows. Three treatments were tested: control diet, supplementation of 250 g/ton of Krave AP-P, and 500 g/ton of Krave AP-P. Results showed that feed flavor improved sow feed intake, going from 5.08 kg/day without supplementation to 6.02 and 6.60 kg/day with 250 and 500 g/ton of Krave AP-P, respectively. Consequently, average daily milk production was also higher in the group supplemented with 500 g/ton of feed flavor, followed by the 250 g/ton and the control group (12.99 vs. 9.55 vs. 8.59 kg/d, respectively). More milk yield was reflected in higher litter average daily gain, and higher piglet weight at weaning. Piglet survivability was also affected: Krave AP-P inclusion in the lactating sow diet promoted a greater number of weaned piglets,
In another research trial conducted on a commercial sow unit during the hot season, evaluated a total of 200 highly-prolific sows divided into 2 treatments, represented by a control diet and a diet including commercial feed flavor Krave AP-P during lactation. All sows were housed individually and had ad libitum access to feed and water. Results from that study also showed that the inclusion of 500 g/ton of Krave AP-P had a significant influence on lactating sow feed intake (6.15 vs. 5.32 kg/day, from the control group), higher litter average daily gain (2.36 vs. 2.06 kg/day), and 14% higher daily milk production when compared with the control group (12.18 vs. 10.67 kg/day). The authors also reported that Krave AP-P can be fed in conjunction with Rovabio – an enzymatic solution from Adisseo – as it improves lactational feed efficiency.
The positive response of Krave AP-P on the highly-prolific sows’ performance seems to be very consistent, especially on animals under hot climates. During the past few years, Silva and his research group have conducted many experiments with Krave AP-P, evaluating its effects on a variety of different genetic lines: 200 PIC Camborough sows ( ); 300 Danbred genetics sows ( ); 300 Landrace x Large White sows (Silva et al., 2017); and 60 TN70® Topigs Norsvin sows (Silva et al., 2021). All the studies reported that the commercial feed flavor significantly improved sow feed intake, with positive consequences on milk production and piglet performance.
In summary, avoiding or minimizing the effects of heat stress is one of the main challenges of modern pig farming. Sows exposed to high environmental temperatures suffer from a significant drop in feed intake and compromised reproductive performance. In contrast, there are several tools to remedy this issue. Feed flavors, such as Krave AP-P , can be used to optimize the sensory properties of feed and improve lactating sow feeding behavior, as well as increase their milk production – especially under heat stress conditions.
Castro Júnior, S. L., & Silva, I. J. O. D. (2021). The specific enthalpy of air as an indicator of heat stress in livestock animals. International Journal of Biometeorology, 65(2), 149-161. Doi: https://doi.org/10.1007/s00484-020-02022-8
Guo, Z., Lv, L., Liu, D., & Fu, B. (2018). Effects of heat stress on piglet production/performance parameters. Tropical animal health and production, 50(6), 1203-1208. Doi: https://doi.org/10.1007/s11250-018-1633-4
Lucy, M. C., & Safranski, T. J. (2017). Heat stress in pregnant sows: thermal responses and subsequent performance of sows and their offspring. Molecular Reproduction and Development, 84(9), 946-956. Doi: https://doi.org/10.1002/mrd.22844
Renaudeau, D., Gourdine, J.L., Quiniou, N., Noblet, J., 2005. Feeding behaviour of lactating sows in hot conditions. Pig News Inf. 26, 17N–22N.
Renaudeau, D., Silva, B.A.N., Gourdine, J.L., Noblet, J., 2008. Nutritional Routes to Attenuate Heat Stress in Pigs, Livestock and Global Climate Change. 17–20/05/08, Hammamet, Tunisia.
Silva, B. A. N., Eskinazi, S., Jacob, D. V., Araujo, W. A. G., Rebordões, F. I. G., Gonçalves, M. F., … & Domingos, R. L. (2021). Feed flavour supplementation improves kinetics of intake and feeding behaviour pattern of lactating sows in a tropical climate. Livestock Science, 250, 104559. Doi: https://doi.org/10.1016/j.livsci.2021.104559
Silva, B. A. N., Tolentino, R. L. S., Eskinazi, S., Jacob, D. V., Raidan, F. S. S., Albuquerque, T. V., … & Alcici, P. F. (2017). Evaluation of feed flavor supplementation on the performance of lactating high-prolific sows in a tropical humid climate. Animal Feed Science and Technology, 236, 141-148. Doi: https://doi.org/10.1016/j.anifeedsci.2017.12.005
St-Pierre, N. R., Cobanov, B., & Schnitkey, G. (2003). Economic losses from heat stress by US livestock industries. Journal of dairy science, 86, E52-E77. Doi: https://doi.org/10.3168/jds.S0022-0302(03)74040-5