Dietary zeolite clinoptilolite supplementation influences chemical composition of milk and udder health in dairy cows

Cilj ovog istraživanja bio je ustanoviti utjecaj zeolita klinoptilolita (KPL) dodavanog u obroke mliječnih krava na kemijski sastav mlijeka, broj somatskih stanica (BSS) i zdravlje vimena. Dvadeset krava Holštajn-frizijske pasmine u dobi od 3 do 5 godina, gravidnih tri mjeseca i držanih u maloj obiteljskoj farmi u okolici Đurđevca, Hrvatska, bile su uključene u ovo istraživanje. Krave su bile nasumično razvrstane u dvije skupine, kontrolnu (n=10) i skupinu hranjenu s dodatkom KPL (n=10), i to svakodnevno sa 100 g zeolita u obroku za mliječne krave. Prvo uzorkovanje mlijeka načinjeno je prije dodavanja KPL u hranu. Još su četiri uzorkovanja provedena kroz četiri mjeseca, do sedmog mjeseca gravidnosti, odnosno suhostaja. Uzorci mlijeka bili su analizirani s obzirom na kemijski sastav mlijeka (mliječna mast, bjelančevine, laktoza, nemasna suha tvar i ureja), BSS i bakteriološkom pretragom. Uočene razlike u sadržaju pojedinog pretraživanog sastojka mlijeka nisu se značajno razlikovale, ni za pojedinačno uzorkovanje niti između pokusnih skupina krava. Međutim, kemijski sastav mlijeka bio je mnogo stabilniji u krava kojima je dodavan KPL u hranu. Naime, statistički značajna razlika između pojedinačnih uzorkovanja u krava kojima je dodavan KPL bila je utvrđena za sadržaj mliječne masti i ureje. Štoviše, u mlijeku krava iz kontrolne skupine utvrđene su značajne razlike između pojedinačnih uzorkovanja za sve pretražene sastojke mlijeka, s izuzetkom nemasne suhe tvari. Broj BSS u mlijeku krava iz obiju skupina nije se značajno razlikovao. Međutim, krave iz kontrolne skupine imale su 21 puta veći rizik od pojave intramamarnih infekcija nego krave kojima je KPL dodavan u hranu. Ovakav povoljni ishod naših istraživanja može se pripisati antibakterijskom, detoksikacijskom, antioksidativnom i imunostimulacijskom učinku KPL na metabolizam krava što se očitovalo padom pojavnosti intramamarnih infekcija tijekom suhostaja, porođaja i rane laktacije. Ovaj ishod vjerojatno bi se mogao objasniti ublažavanjem stresnih stanja tijekom spomenutih razdoblja kada su krave najosjetljivije na metaboličke poremećaje i nepovoljne okolišne uvijete koji rezultiraju u izraženijoj imunosupresiji i prijemljivosti za intramamarne infekcije.The aim of the current study was to establish the influence of dietary zeolite clinoptilolite (CPL) on the chemical composition of milk, somatic cell counts and udder health in dairy cows. Twenty cows of the Holstein-Frisian breed, aged between 3 and 5 years, which were pregnant for 3 months and kept in a small family farm in vicinity of Đurđevac, Croatia, were included in the trial. Cows were randomly assigned into two groups, control (n=10) and CPL-fed group (n=10). The CPL group received 100 g zeolite in the ratio for dairy cows on a daily basis. The first milk sampling was taken prior to adding CPL to feed. The four consecutive samplings were performed on a monthly basis up to 7th month of pregnancy, i.e., the dry period. The milk samples were analysed for chemical composition (milk fat, proteins, lactose, non- fatty dry matter and urea), somatic cell counts and by bacteriological examination. Observed differences in the content of particular milk components tested did not differ significantly between groups in any of sampling points. However, the chemical composition of milk was found to be more stable in CPL-fed cows. Statistically significant differences were found for milk fat and urea contents between single samplings in CPL-fed cows. Moreover, in the control group, significant differences were found between single samplings for all milk components, except non-fatty dry matter. The number of SCC in milk between the groups did not differ significantly. However, the control cows had a 21-fold higher odd of intramammary infections than CPL-fed cows. This beneficial outcome of the study may be attributed to the antibacterial, detoxifying, antioxidative and immunostimulating effects of CPL on the metabolism of cows, as exhibited by a decreased incidence of intramammary infections during the dry period, parturition and early lactation. Such an outcome might be explained by the moderation of stressful events accompanying such periods, when cows are the most sensitive to metabolic imbalance and environmental detrimental effects, resulting in more pronounced immunosuppression and susceptibility to intramammary infections