Effects of some pasture types on liveweight gains and thyroid size of guinea‐pigs

Two feeding experiments with guinea‐pigs are described. In the first, 4 pasture types (perennial and short‐rotation rye grasses with and without white clover) were fed to guinea‐pigs, 5 animals being used for each treatment. In the second experiment, the 2 ryegrasses were ovendried and fed at 2 intake levels with 5 guinea‐pigs on each treatment. Multiple covariance analysis showed that most of the variance in liveweight gain could be accounted for in terms of DM percentage and DM intake. Thyroid gland enlargements were noted on several treatments. Possible reasons are discussed.