A randomized controlled trial on the effect of incomplete milking during early lactation on ketonemia and body condition loss in Holstein dairy cows

Abstract

Limiting milk production for a short period of time in early lactation could be a relevant strategy to prevent hyperketonemia (HYK). From December 2013 to March 2015, 838 multiparous Holstein cows from 13 herds were enrolled in a randomized controlled trial evaluating the effect of incomplete milking in early lactation on ketonemia and its effect on body condition score (BCS) loss. Cows were randomly assigned 4 wk before expected calving date to 1 of 2 treatment groups, (1) a conventional milking protocol (CON) for which cows were completely milked or (2) an incomplete milking protocol (INC) for which a maximum of 10 to 14 kg of milk/d were withdrawn during the first 5 d in milk (DIM). β-Hydroxybutyrate (BHB) concentrations were measured from blood samples collected on each cow 3 times at weekly intervals. Hyperketonemia was defined as BHB ≥1.4 mmol/L. Body condition score variation in the postcalving period was calculated by subtracting BCS assessed at wk 7 from BCS assessed at first week after calving. Effect of treatment on ketonemia and prevalence of HYK were evaluated for 4 specific time periods: 1 to 3, 4 to 7, 8 to 17, and 18 to 26 DIM. Effect of treatment on ketonemia was investigated using linear mixed models with natural logarithm of BHB measurements as outcome and treatment groups as fixed effect. Generalized linear mixed models with HYK as outcome, using logit link, and treatment groups as fixed effect were used to investigate effect of treatment on odds of HYK. A logistic regression model with BCS loss (<0.75 or ≥0.75) as outcome and treatment groups and herd as fixed effects was used to study effect of INC on odds of having BCS loss ≥0.75. A total of 813 lactations had complete data and were used for statistical analysis of ketonemia and HYK. A total of 709 lactations had complete data and were used for analysis of BCS loss. Geometric means of blood BHB concentrations during the 1 to 3, 4 to 7, 8 to 17, and 18 to 26 DIM periods were, respectively, 0.72 (95% confidence interval = 0.66, 0.80), 0.66 (0.60, 0.73), 0.90 (0.80, 1.01), and 0.93 (0.83, 1.05) mmol/L for INC, and 0.65 (0.59, 0.72), 0.79 (0.72, 0.87), 0.94 (0.84, 1.06), and 0.92 (0.82, 1.04) mmol/L for CON. Cows in INC group had lower ketonemia during the 4 to 7 DIM period. Predicted prevalence of HYK during the 1 to 3, 4 to 7, 8 to 17, and 18 to 26 DIM periods were, respectively, 2.8 (3.2, 15.1), 4.6 (2.0, 10.0), 13.4 (8.4, 20.0), and 23.0% (17.4, 29.7) for INC and 2.6 (2.5, 13.8), 10.7 (5.6, 19.3), 19.4 (13.0, 27.9), and 21.3% (16.0, 27.8) for CON. The INC treatment reduced the prevalence of HYK during the 4 to 7 and 8 to 17 DIM periods. No association was observed between INC and BCS loss in the postcalving period. Overall, the incomplete milking protocol was effective for reducing ketonemia and prevalence of HYK during the early postpartum period.

A randomized controlled trial on the effect of incomplete milking during the first 5 days in milk on culling hazard and on milk production and composition of dairy cows

“…Finally, Roberts et al (2012) found that odds of culling within the first 60 DIM were increased by 1.8 in cows presenting hyperketonemia (BHB blood concentration ≥1.2 mmol/L) during the first WIM. As the incomplete milking was found to reduce odds of hyperketonemia (Carbonneau et al, 2012;Morin et al, 2018), we would have expected to observe a preventive effect of the incomplete milking on culling; however, this was not the case in our study. Many internal (e.g., parity, health status) and external (e.g., need for producing more milk, milk/price) factors will affect the producer's decision whether to cull a cow (Bell et al, 2010).…”

“…The original study was designed to investigate the effect of an incomplete milking protocol on ketonemia, odds of hyperketonemia, reproductive performances, odds of infectious diseases (e.g., mastitis, metritis), culling hazard and, finally, milk production and composition (Krug et al, 2017;Morin et al, 2018). Among all the outcomes studied, the outcome requiring the largest sample size was odds of hyperketonemia, which required the recruitment of 400 cows per treatment group (Morin et al, 2018). The sample size for the RCT described in our study was, therefore, determined for answering this latter research objective.…”

“…Our study was an RCT conducted on multiparous cows from a convenient sample of 13 commercial dairy farms. The complete research protocol is described by Morin et al (2018). Briefly, to be selected, farms had to be in the vicinity of Saint-Hyacinthe (Quebec, Canada); to accept to follow the standardized research protocol; to participate in a DHIA program; to have computerized health records; to use a milking system allowing measurement of the harvested milk in real time during milking; and to share their herd health, DHIA, and daily milk weight (if available) data with the research group.…”

“…These results cannot, consequently, be generalized to commercial farms. Therefore, a randomized controlled trial (RCT) was conducted on 13 commercial dairy farms to evaluate the effect of an incomplete milking protocol (Morin et al, 2018). The RCT showed a marked decrease in BHB blood concentration and in odds of hyperketonemia among cows milked incompletely.…”

“…The RCT showed a marked decrease in BHB blood concentration and in odds of hyperketonemia among cows milked incompletely. The aim of the present research was to investigate the effect of the incomplete milking protocol on culling hazard and on milk production and composition using the large data set generated by the Morin et al (2018) study.…”