Dairy

Hyperketonemia (HYK), defined by blood beta-hydroxybutyrate (BHB) ≥ 1.2 mmol/L, is described as a significant risk factor for cows developing postpartum (pp) diseases and impaired reproductive performance. The goal of the present study was to observe metabolic challenges in transition cows and to identify systemic markers reflecting HYK associated with lessened reproductivity. Fifty-four Simmental cows were monitored, revealing approximately 30% prevalence of HYK at the early pp period on 7, 14, or 28 days in milk (DIM). We assessed the dry matter intake, rumination time (RT), serum liver activity index, non-esterified fatty acids (NEFAs), acute phase proteins, and uterine and oviductal health. Elevated NEFA and reduced RT 14 days antepartum were a good predictor for HYK at 7 DIM. Hyperketonemia at 14 DIM resulted in higher milk yield compared with controls. We could neither detect differences in uterine health nor in reproductive key performance parameters between hyperketonemic and control cows, whereby the proportion of polymorphonuclear neutrophils in oviductal epithelia was significantly lower in hyperketonemic cows 14 DIM. We conclude that elevated concentrations of BHB in HYK 7, 14, or 28 DIM indicated energy supply to support physiological metabolic adaptations and lactation and that, in the absence of excessive inflammation during the transition period, HYK was not a risk factor for impaired fertility.

We evaluated the effects of rapeseed oil (RSO, rich in oleic, linoleic, and linolenic acids) and a commercial fat source (BOVI-LM, rich in palmitic and stearic acids) on the growth performance and blood biochemical parameters of dairy calves during the pre- and post-weaning phases. Eighteen crossbred bull calves were randomly allocated in a randomized complete block design to three dietary treatments (Control, RSO, and BOVI-LM) during the milk-replacer phase (Phase 1, days 0–28). Due to technical issues, BOVI-LM supplementation was discontinued in Phase 2 (starter-feed phase, days 35–77), leaving only Control (n = 12) and RSO (n = 6). Energy supply was calculated to support target average daily gains of 0.6 (Phase 1) and 1.0 kg (Phase 2). Body weight, clinical health, and blood samples for biochemical analysis were monitored throughout the trial. No treatment effect on body weight or blood biochemical parameters was detected (main effect of treatment: p ≥ 0.18 for all analytes). In contrast, phase and time effects were significant for most biochemical parameters (p < 0.05), reflecting the metabolic transition from a milk-based to a solid-feed diet. Aspartate aminotransferase activity increased over time (p < 0.001), whereas glucose concentrations decreased post-weaning (time × phase: p = 0.020). The treatment × phase interaction was non-significant for all variables (p ≥ 0.13), supporting the absence of detectable carry-over effects and justifying the pooling of former BOVI-LM calves into the Control group in Phase 2.

This study examines the critical role of whole milk or milk replacer as a liquid diet (LD) with 15% solids in combination with different physical forms of starter as a solid diet (SD), on performance, health, and behavior of pre-weaned calves. Sixty male Holstein calves were used in a 2 × 2 factorial design, and randomly distributed into the following treatments: Whole milk powder diluted to 12.5% of solids and enriched with 25 g/L of milk replacer to achieve 15% solids, associated with either micropelleted stater (WM+micro) or texturized stater (WM+text); milk replacer diluted to 15% solids associated with either micropelleted stater (MRmicro) or texturized stater (MRtext). Starter intake and, consequently, total DMI were higher in the MRtext treatment compared to WM+micro. Calves fed texturized starter showed higher DMI, starter intake time, and rumination time. Calves in the WM+Text group showed greater ADG compared with MR treatments, regardless of starter type. Calves fed WM+ presented a lower number of days with fecal score ≥2, and the first day of diarrhea occurred at older ages. Calves fed MR showed more health challenges but similar feed efficiency with WM+, while texturized starter increased intake, eating duration, and rumination compared with micropelleted starter.