Effects of oral supplementation with organically modified clinoptilolite during prepartum period on colostrum quality in primiparous dairy cows.

This research paper addresses the hypothesis that an oral supplementation with organically modified clinoptilolite will improve colostrum quality in primiparous dairy cows whilst having no adverse effects on the cows' health. A total of 36 pregnant Holstein primiparous dairy cattle were randomly assigned to receive daily oral drenching, two hours following morning feeding, with 1 l of water containing either 0 g/l (n = 16) or 150 g/l (n = 20) of clinoptilolite. Treatment lasted from 24 ± 4 d prior to expected parturition until two days postpartum (pp). Colostrum was collected at 2 to 3 h, 12, 24 and 36 h pp and blood samples were collected at 24 ± 4 and 4 ± 2 d prior to parturition and 1, 2 and 7 d pp. Overall mean dry matter, fat and total protein percentage as well as IgG concentration and mass were significantly greater in colostrum collected from cattle drenched with clinoptilolite (total protein increased by 15% and IgG concentration and mass by 21 and 38% respectively at first sampling and further at second sampling). Total γ globulin and most other blood serum biochemistry parameters did not differ between cattle treated and not treated with clinoptilolite, the only exception being the fast anionic γ globulin fraction that was 17% greater at 4 ± 2 d prior to parturition and 10% lower on the 1st day pp in treated cattle. These results showed that organically modified oral clinoptilolite supplementation at 150 g/d significantly increases the IgG concentration in colostrum and has no adverse effects on the energy status, protein, lipid, and mineral metabolism in primiparous dairy cattle during prepartum period.

Progesterone concentration, pregnancy and calving rate in Simmental dairy cows after oestrus synchronisation and hCG treatment during the early luteal phase.

Early embryonic development may be negatively affected by insufficient progesterone (P4) production. Therefore, the aim of our study was to increase P4 by gonadotropin-releasing hormone (GnRH) and/or human chorionic gonadotropin (hCG) treatments after inducing oestrus by prostaglandin (PG) treatment. Lactating Simmental dairy cows (n = 110), between 1 to 5 lactations, with an average milk production of 6,500 1/305 days, at 40-80 days postpartum were used and grouped as follows: (1) PG + GnRH treatment at AI (GnRH group), (2) PG + hCG treatment at day 7 after AI (hCG group), (3) PG + GnRH at AI + hCG treatment at day 7 after AI (GnRH/hCG group), and (4) spontaneous oestrus (C: control group). All animals were double inseminated (at the time of oestrus detection and 12 ± 2 h thereafter). Blood serum and milk samples were collected at the day of observed oestrus (day 0), and 14, 21 and 28 days after AI. Serum P4 was determined using a commercial radioimmunoassay (RIA) test (INEP, Zemun), and milk P4 was determined using enzyme-linked immunoassay (ELISA) test (NIV Novi Sad). Pregnancy status was confirmed by ultrasonography between days 28 and 35 after AI. Differences of serum or milk P4 medians, pregnancy (and calving) rate were determined using Dunn's Multiple Comparison Tests and Z test, respectively. Serum P4 medians were significantly higher at days 14, 21 and 28 after AI in the hCG-treated animals, indicating increased luteal activity, with a similar tendency in whole milk P4 values. Treatment with hCG during the early luteal phase significantly contributed to the maintenance of gestation at days 28-35 after AI, and also increased the calving rate in Simmental dairy cows.