Our colleagues in the College of Food, Agricultural and Natural resource Sciences (CFANS) have shared one of their latest projects with the National Hog Farmer readers. They found that adding higher amounts of zinc in the late-gestation diet of sows in both a research and commercial herd increased the survival of smaller piglets until they are weaned.
The first study was done 220 gilts with an average of 10.6 piglets total born and a pre-weaning mortality of 8.3%. A higher inclusion of zinc sulfate (at a rate of 0.07%) decreased the pre-weaning mortality rate from 100% to 40% in piglets of less that 1.1 lbs at birth.
To confirm this finding, the experiment was repeated on 339 sows from a commercial herd. The sows were given either a traditional diet, or a diet with an intermediate amount of zinc or a diet with a high amount of zinc during the last 40 days of gestation.
No effect was found on the number of piglets total born or piglets weaned nor did zinc influence the number of stillborn of mummies. The effect of zinc on birth weight was not significant either. However, increasing the amount of zinc decreased the overall pre-weaning mortality from 15.0% to 12.2% and even more dramatically from 38.3% to 28.1% in piglets with a low birth weight (less than 2.2 lbs).
Even though, post-weaning performances were not influenced by the amount of zinc fed to the sows during late gestation, it is interesting to see its effect on pre-weaning mortality for low-weight piglets. More research is needed to explain the mechanisms behind such findings as zinc is a mineral involved in many metabolic pathways throughout the pig’s body.