Effects of calcium to phosphorus ratio in the diet of dairy cows on incidence of parturient paresis
Beitz, D.C.; Burkhart, D.J.; Jacobson, N.L.
Journal of Dairy Science 57(1): 49-55
Jersey and Ayrshire cows (19 and 3 cows at 26 parturitions, 2nd lactation or beyond) were allotted to 2 groups according to lactation number and milk production. Two cows in each group had had parturient paresis during previous lactations and 2 in each group were on experiment for 2 consecutive parturitions. One group had a diet with Ca:P ratio 1.1:1, and the other group a ratio of 2.3 from at least one month before parturition. Blood samples were withdrawn weekly beginning 4 weeks before parturition and the interval was reduced regularly until over parturition it was 3 h then widened again to weekly till 4 weeks post partum. Cows developing parturient paresis were treated with calcium borogluconate solution free of Mg and P. In 7 of the 14 parturitions of cows on the Ca:P 1.1 diet and in 9 of 12 on the Ca:P 2.3 diet, treatment for parturient paresis was required. The time for which the diets were given before parturition had no obvious effect on incidence of parturient paresis. Plasma Ca and inorganic P were lower 48 h prepartum to 48 h postpartum in paretic than in nonparetic cows. Nonparetic cows on the 2.3 diet had a higher plasma Ca concentration from 48 h to 4 weeks postpartum than nonparetic cows on the 1.1 diet. There was no other significant dietary effect on plasma Ca, Mg or P.