Experience of using the bolus for preventing hypocalcemia of cows in the fresh period

Relevance and methods. Postpartum paresis is one of the serious complications in high-yielding cows after calving affecting the course of the entire lactation, so the focus of attention is on the choice of means of prevention. For these purposes, in the conditions of the breeding farm named after the 50th anniversary of the USSR (Vologda region), the effect of Calci-mix calcium bolus produced by “Agrokon-Vologda” LLC was studied. The cows of the control group were not injected with bolus, the animals of the I experimental group were injected twice — the first time immediately after calving and after 12 hours, the II experimental group — two boluses at once. Results. During the dry period, the main blood counts of all cows were within the normal range, but after calving before the introduction of the bolus, the calcium content decreased (to 32.8%). On the 1st day after bolus administration, the calcium concentration in cows of the experimental group I was 27.9% higher ( p ≤ 0.01), II — by 44.2% (p ≤ 0.01). On the 3rd day in the I and II experimental groups, the calcium content was within the normal range — 2.44 mmol/l (p ≤ 0.05) and 2.43 mmol/l. In the control group, throughout the entire experiment, the calcium concentration was below normal, which led to a decrease in the Ca/R value. The introduction of a bolus allowed to increase the level of ionized calcium in the I and II experimental groups (by 13.3% and 21.2%) and to shift the Ca/R ratio upwards. Thus, the use of bolus had a positive effect and contributed to the replenishment of the lack of Ca in cows in the postpartum period. Taking into account the fact that the introduction of a bolus with a time interval often occurs at night, we consider the most appropriate single injection of two boluses to cows immediately after calving.