R. Blauwiekel et al., EFFECT OF WHOLE COTTONSEED, GOSSYPOL, AND RUMINALLY PROTECTED LYSINE SUPPLEMENTATION ON MILK-YIELD AND COMPOSITION, Journal of dairy science, 80(7), 1997, pp. 1358-1365
To determine whether the gossypol content of the diet affected availab
ility of dietary Lys, 4 cows with ruminal and duodenal cannulas and 16
intact cows in early lactation were assigned to diets containing eith
er glanded cottonseed, glanded cottonseed plus 15 g/d of ruminally pro
tected Lys, glandless cottonseed, or glandless cottonseed plus 15 gld
of ruminally protected Lys. The experimental design was a 4 x 4 Latin
square design with 3-wk experimental periods. Gossypol concentrations
in plasma were lower when cows were fed glandless cottonseed. Lysine s
upplementation increased the flow and percentage of Lys in duodenal di
gesta and increased the concentration of Lys in plasma. Neither type o
f cottonseed nor Lys supplementation affected dry matter intake. Yield
s of milk and fat-corrected milk from cannulated cows were not affecte
d by diet, but yields from intact cows were increased by Lys supplemen
tation. For both cannulated and intact cows, Lys supplementation incre
ased the percentage of milk protein, and milk protein yield was increa
sed by Lys in intact cows. Dietary gossypol did not affect the respons
e to Lys, indicating that dietary gossypol had little or no effect on
the availability of Lys for dairy cows.