hrvatski

The influence of dietary clinoptilolite on reproductive performance and serum levels of some minerals in Holstein-Friesian heifers and cows

The aim of this study was to determine the influence of dietary clinoptilolite (CPL) on serum levels of Ca, Mg, P, K and Na of Holstein Friesian heifers (n=20) and cows (n=20) during late pregnancy and early lactation and their reproductive performance. They were randomly assigned into 2 groups (each containing 10 cows and 10 heifers): the CPL-treated group that received 100 g CPL in feed from 60 days ante partum (ap) to 40 days post partum (pp), and the control group (CON) of untreated animals. Blood samples were taken on days 30 ap, 10 ap, on the day of calving and on days 5, 19, 33, and 40 pp. There was a significant difference in Ca levels between the CPL and CON groups (2.41±0.16 vs. 2.28±0.12 mmol/L, respectively) 30 days ap. The Ca level was higher in the CPL group than in the CON group (2.60±0.14 vs. 2.19±0.13 mmol/L, respectively ; P<0.05) on day 33 pp. The serum level of P was significantly lower (P<0.05) in the CPL group, though only on day 5 pp (1.68±0.28 vs. 1.90±0.21 mmol/L, respectively). There were no significant differences observed in Na, K and Mg serum levels between the groups. To assess reproductive performance the following variables were registered: days open to first service (DFS), days open to pregnancy (DOP), and number of services per pregnancy (NSP). Also, DFS (P<0.05) and DOP (P<0.05) were shorter in the CPL than in the CON group (109.85±25.78 and 130.15±29.36 days vs. 122.4±22.42 and 141.15±22.04 days, respectively). The NSP was lower in the CPL than in CON group (1.93 vs. 2.17). Mixed modules were used with random effect of animal with repeated samplings/observations over time was included in the model. In conclusion, dietary vibroactivated and micronized CPL improved the mineral profile and their reproductive performance.

zeolite ; cow ; minerals ; reproduction

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