This study was aimed to assess the effect of adding clinoptilolite in the diet on uterine health and reproductive performance in multiparous lactating dairy cows managed in a tropical pasture-based system above 2500 meters of altitude. Seventy-seven multiparous Holstein crossbred cows were allocated randomly into two groups: clinoptilolite supplemented cows (CLG, n = 42) and non-supplemented cows as control (CG, n = 35). Cows from CLG were supplemented with clinoptilolite from 30 days (50 g/cow/day) before to 60 days after calving (200 g/cow/day). Data were analyzed by general linear model, least squares means and chi-square test of SAS. In CLG cows, percentages of uterine PMN leukocytes (P<0.0001) and proportion of subclinical endometritis (P=0.0187) were lower than in CG. The interval calving to first corpus luteum was shorter (P=0.0759) in CLG than CG, and calving to first service interval was similar between treatments. Cows from CLG became pregnant 35 days earlier than CG cows (P=0.0224). In conclusion, daily addition of clinoptilolite in the diet decreased the proportion of cows with subclinical endometritis and shortened the interval from calving to conception in lactating dairy cows.

This study was aimed to assess the effect of adding clinoptilolite in the diet on uterine health and reproductive performance in multiparous lactating dairy cows managed in a tropical pasture-based system above 2500 meters of altitude. Seventy-seven multiparous Holstein crossbred cows were allocated randomly into two groups: clinoptilolite supplemented cows (CLG, n = 42) and nonsupplemented cows as control (CG, n = 35). Cows from CLG were supplemented with clinoptilolite from 30 days (50 g/cow/day) before to 60 days after calving (200 g/cow/day). Data were analyzed by general linear model, least squares means and chi-square test of SAS. In CLG cows, percentages of uterine PMN leukocytes (P<0.0001) and proportion of subclinical endometritis (P=0.0187) were lower than in CG. The interval calving to rst corpus luteum was shorter (P=0.0759) in CLG than CG, and calving to rst service interval was similar between treatments. Cows from CLG became pregnant 35 days earlier than CG cows (P=0.0224). In conclusion, daily addition of clinoptilolite in the diet decreased the proportion of cows with subclinical endometritis and shortened the interval from calving to conception in lactating dairy cows.