SUMMARY

Lindemann, M. D., S. D. Carter, L. I. Chiba, C. R. Dove, L. L. Southern, and S-288 Regional Research Committee on Nutrition and Management of Swine for Increased Reproduction Efficiency.

Supplementation of sows with chromium tripicolinate has shown some promising increases in litter size. However, the effect of various levels of picolinate supplementation has not been examined.

This study was conducted to evaluate multiple levels of Cr supplementation across a variety of conditions at five universities. A common corn-soy diet was formulated to meet or exceed the NRC (1988) requirement estimates for sows. Supplemental levels of 0, 200, 600, and 1,000 ppb Cr from chromium tripicolinate were used. The 600 ppb provides the mature animal with a similar Cr supply per kg of BW as a growing pig fed 200 ppb Cr. The 1,000 ppb is 5 times the standard supplementation level of 200 ppb Cr. Participants were required to use at least three of the four levels, including 0 and 200 ppb Cr. A total of 285 gilts and sows were allotted to treatments on the day of breeding. Only those sows completing at least two parities were considered in the data analysis. A total of 439 litters (the experimental unit) were included in the statistical analysis. The model included terms for station, treatment, study parity, and all possible interactions.

There were significant station effects for all measured responses, but no "meaningful" station x treatment interactions were observed. With regard to litter size, which was the primary interest of response, a tendency for an increase in total pigs born/litter with increasing Cr supplementation was observed (10.17 , 10.86, 11.09, and 10.53, respectively; P = 0.14). The litter size responses in live born (9.27, 9.59, 10.12, and 9.71) and weaned (8.30, 8.47, 9.00, and 8.83) followed the same pattern, but were not statistically significant.

In summary, supplementation of 200 ppb Cr from chromium tripicolinate resulted in the increase in mean litter size similar to published literature. Numerical increases in litter size beyond that observed at 200 ppb may suggest the need for a continued research to evaluate the effect of higher supplementation rates. The level of five times the current supplementation rate was not detrimental to sows, even though 1,000 Cr from chromium tripicolinate was fed up to three parities.

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