engleski

EFFECTS OF IN-FEED ZEOLITE TREATMENT ON LIPID PROFILE IN DAIRY COWS DURING TRANSITION PERIOD

The main metabolic changes in cows occur during the transition period. Metabolic disturbances are characterized by high quantities of NEFA from adipose tissue which in the process of ketogenesis enter into the liver, resulting in the increased production of ketone bodies, or its re sterification into triglycerides (TG), causing fatty liver syndrome. Tendency to mobilize body fat reserves very rapidly, due to increased NEFA concentrations, are risk factors for the development of many peripartal diseases in dairy cows. A total of 20 dairy cows of the Holstein- Friesian breed, between 2 and 6 years of age, were included in this study. They were housed in a free-stall barn with straw bedding and kept on farm in Croatia (coordinates 45°59′ N, 17°03′ E). Cows were randomly assigned into two groups: the treated group that received clinoptilolite (CPL) in-feed (n=10), i.e. 50 g natural powdered CPL modified by vibroactivation and micronization (Vibrosorb®, Viridisfarm, Podpićan, Croatia) twice daily from 7th month of pregnancy to the end of observation ; and the control (CON) group of non- treated cows (n=10). Animals were randomly selected according to body condition score from 2.75 to 3.50 (scale 1-5). For determination of lipid status, samples were taken on days 30 and 10 before expected calving, on the day of calving, and on days 5, 26 and 33 after parturition. The cows were fed of haylage, corn silage, hay and a complete feed mixture for dry cows and lactating cows with 19% of crude protein. Triglycerides (TGL), total cholesterol (TCH), high density lipoprotein cholesterol (HDLC), were determined by Beckman Coulter AU 680 biochemical analyser (Beckman Coulter Biomedical Ltd. München, Germany) and serum BHB and NEFA concentrations by the use of Randox kits (Randox Laboratories Ltd., Crumlin, UK). There were no significant differences observed in TCH, TGL and HDLC concentration between cows in the CPL and CON group (3.79±1.38, 0.13±0.05 and 2.41±0.76 mmol/L, vs. 3.80± 1.32, 0.13±0.04 and 2.41±0.72 mmol/L, respectivly). In both groups, HDLC and TCH concentration was decreased around parturition. The BHB concentration was decreased (P < 0.05) in the CPL group on days 5 and 26 after parturition compared to the CON group (1.90±0.89, 2.05±1.22, vs. 1.27±0.82, 1.57±1.23 mmol/L, respectivly). The NEFA concentrations were increased on the day of parturition and on days 5 and 26 after parturition in both groups in comparison to values before parturition, but in CON 99 group had greater NEFA concentrations (P < 0.05) on mentioned days (1.07±0.50, 1.43±0.54 and 0.92±1.03 vs. 0.71±0.62, 0.89±0.43 and 0.48±0.15 mmol/L, respectively) than in CPL group. The results of this study suggest that the cows supplemented with CPL may have improved lipid status due to decreased BHB values and to the positive effect on the intensity and severity of negative energy balance in dairy cows during early lactation.

BHB ; dairy cows ; lipid status ; NEFA

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