September 2021


The main objective of this study was to evaluate the effect of peripartal administration of a commercially available nonspecific immune stimulant (mycobacterium cell wall fraction; MCWF [Amplimune, NovaVive Inc., Napanee, ON, Canada]) on the incidence of disease during early lactation and subsequent fertility of dairy cows. A second objective was to characterize the dynamics of circulating white blood cells (WBC) and metabolic markers following treatment administration. Cows in an United States Department of Agriculture (USDA) organic-certified dairy herd were blocked by parity and, based on sequential calving dates, randomly assigned to receive two injections (5 mL s.c.) of either a placebo (saline solution) as a control (CON; n = 71) or MCWF (n = 65) at enrollment (7 d before expected calving) and within 24 h after calving. Blood samples were collected from a subsample of the study population (MCWF = 16; CON = 18) for WBC count at enrollment, at day 2 post enrollment, and at days 1, 3, 7, and 14 after calving. Serum fatty acids, beta-hydroxybutyrate, and Ca concentrations were determined at days 1 and 7 postpartum (MCWF = 21; CON = 21). Main outcome variables included incidence risk of peripartal and early lactation health disorders and pregnancy at first artificial insemination (AI), at 100, and at 150 days in milk (DIM). In addition, the average daily milk yield up to 90 DIM and death and live culling before 305 DIM were compared. Treatment effects were assessed using multivariable logistic regression, time-to-event analyses, and repeated measures analysis of variance (ANOVA). A treatment effect on the incidence risk of some of the health disorders in the study was established. Incidence risk of metritis and clinical mastitis

Gilberto Solano-Suárez, Luciano S Caixeta, Alexander Masic, Diego Manríquez, Luciana Hatamoto-Zervoudakis, Sushil Paudyal, Ana Velasquez-Munoz, Juan Velez, Pablo J Pinedo
Journal of Animal Science, Volume 99, Issue 9, September 2021, skab191,