There was a non-significant rise in pituitary lh concentration from Day 7 post partum (2·07 μg/mg fresh anterior pituitary) to Day 30 post partum (2·62 μg/mg). Neither nursing of calves nor anaemia caused a significant change in pituitary lh content. Both control and thyroprotein-fed non-post partum cows had significantly higher levels of pituitary lh, 7·4 μg and 6·9 μg respectively, than did the post partum cows.
There was no detectable tsh in pituitaries of five of six thyroproteinfed cows. tsh concentration ranged from 2·0 to 9·5 mu nih-tsh-b3/mg fresh pituitary in the remaining animals, but there were no significant differences between any of the groups. Thyroprotein-fed animals also had significantly lower thyroid cell heights than all other groups.
Adrenal data indicate a positive correlation exists between progesterone and cortisol in the same gland (r = 0·67, P<0·01). The only group difference of significance was that the nursed group had a significantly lower adrenal progesterone than did the milked group (0·63 versus 1·76 μg/g). Cortisol content was also lower in the nursed animals, but not to a significant extent.