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The high-producing sows have an increased demand on the nutrient availability for milk production in order to nurse and wean more than 12 piglets. Several studies have demonstrated a higher litter growth rate when increasing dietary protein. Therefore, the study was conducted to study the effect of increasing the dietary protein for hyper-prolific lactating sows. In total 544 sows (parity 1–4) were allotted to one of six treatments from day 2 post-partum until weaning. The diets were analysed to have a standardized ileal digestible (SID) crude protein (CP) level of 104.3, 113.3, 120.9, 128.5, 139.2 or 150.0 g/kg. Litters were standardized at day 2 post-partum as 14 piglets and the body weight (BW), back fat (BF) thickness of sows and litter weight were recorded. The BW, BF thickness and litter weight were also recorded at weaning. A subsample of 70 sows (parity 2 and 3) was used to collect milk samples at day 3, 10 and 17 of lactation and analysed for fat, CP and lactose. The dietary SID CP concentration was used as explanatory variable for the dose-response analysis. The abovementioned response variables were fitted using different regression models.
Sow BW and BF loss reached a break point at 143 g SID CP/kg and 127 g SID CP/kg, where sows lost 0.58 kg/d and 3 mm, respectively. Multiparous sows had a higher average daily gain of the litter than first parity sows (3.07 vs. 2.53 kg/d) at the break point at 135 g SID CP/kg, but litter size (13.0 ± 1.2 piglets) at weaning was unaffected by dietary treatments. Milk CP increased to 5.0 g/100 mL until a breakpoint at 136 g SID CP/kg, milk lactose decreased until a breakpoint at 120 g SID CP/kg to 5.3 g/100 mL and milk fat increased linearly. The daily output of milk protein was increased at day 17 until a breakpoint at 130 g SID CP/kg (663–670 g/d). The content of milk fat increased linearly with increasing dietary SID CP. There was a tendency towards an increased number of total born piglets in next litter with increased dietary SID CP, whereas the weaning-to-oestrus interval was unaffected by treatment.
This study showed that increasing dietary SID CP to 135 g/kg feed or 850 g/d improved litter growth rate by increasing milk yield and protein output in milk. Besides, the BW loss of lactating sows was minimized.
Strathe, A. V., Bruun, T. S., Geertsen, N., Zerrahn, J. E., and Hansen, C. F. (2017). Increased dietary protein levels during lactation improved sow and litter performance. Animal Feed Science and Technology, 232, 169-181. https://doi.org/10.1016/j.anifeedsci.2017.08.015
