Barraza M L, Coppock C E, Brooks K N, Wilks D L, Saunders R G, Latimer G W
Department of Animal Science, Texas A & M University, College Station 77843.
J Dairy Sci. 1991 Oct;74(10):3457-67. doi: 10.3168/jds.S0022-0302(91)78536-6.
Thirty-two lactating cows were fed ad libitum diets with 1) 18.7% soybean meal, 2) diet 1 plus 500 ppm supplemental Fe from FeSO4.H2O, 3) 15% whole cottonseed, or 4) diet 3 plus 500 ppm Fe from FeSO4.H2O. Dry matter intakes were similar except for cows fed diet 2, which was lower. Cows fed whole cottonseed diets ingested 23 g/d of free gossypol per cow. Free gossypol apparently excreted was lower than its intake. Iron excretion was similar to Fe intake. Blood metabolites and productive performance did not differ among the diet groups. No signs of gossypol toxicity were observed. Twelve neonatal Holstein male calves were fed a commercial milk replacer for 4 wk, then were allowed ad libitum access to diets with 1) 27% soybean meal, 2) 50% whole cottonseed, or 3) diet 2 plus 500 ppm Fe from FeSO4.H2O. Dry matter intakes were similar but slightly lower for calves fed diet 3. Daily individual intakes of free gossypol from diets 2 and 3 were 2 g, which was lower than the expected 4 g due to an apparent effect of pelleting. Blood metabolites did not differ among the groups, and calves averaged about .6 kg of daily gain on these diets. A follow-up study showed that pelleting reduced free gossypol by as much as 70% in whole cottonseed and by 48% in cottonseed meal. Pelleting represents a mechanism to decrease the toxicity of gossypol in cottonseed products.
32头泌乳奶牛自由采食以下日粮：1）含18.7%豆粕的日粮；2）日粮1加500 ppm由FeSO₄·H₂O提供的补充铁；3）含15%全棉籽的日粮；4）日粮3加500 ppm由FeSO₄·H₂O提供的铁。除采食日粮2的奶牛干物质摄入量较低外，其他组干物质摄入量相似。采食全棉籽日粮的奶牛每头每天摄入23克游离棉酚。明显排出的游离棉酚低于摄入量。铁的排出量与铁摄入量相似。各日粮组间血液代谢物和生产性能无差异。未观察到棉酚中毒迹象。12头新生荷斯坦雄性犊牛先饲喂4周商业代乳料，然后自由采食以下日粮：1）含27%豆粕的日粮；2）含50%全棉籽的日粮；3）日粮2加500 ppm由FeSO₄·H₂O提供的铁。犊牛的干物质摄入量相似，但采食日粮3的犊牛干物质摄入量略低。日粮2和日粮3中犊牛每天个体游离棉酚摄入量为2克，由于制粒的明显作用，低于预期的4克。各组间血液代谢物无差异，这些日粮下犊牛平均日增重约0.6千克。一项后续研究表明，制粒可使全棉籽中游离棉酚减少多达70%，棉籽粕中减少48%。制粒是降低棉籽产品中棉酚毒性的一种机制。
