This study evaluated the effects of rumen-protected Schizochytrium powder on physiological responses, antioxidant capacity, and lactation performance in dairy cows subjected to heat stress (HS). A total of 30 Holstein dairy cows in mid-lactation (181 ± 32 DIM; 29.0 ± 3.1 kg milk yield) were divided into 2 blocks based on milk yield and were then randomly assigned to 1 of 3 groups (n = 10 cows per group): a control group (CON), an uncoated Schizochytrium powder (USP) group, and a coated Schizochytrium powder (CSP) group.

Arginine is one of the most versatile among the AA because of its important role in multiple functions of the body. However, the effect of Arg supplementation on lactational performance in dairy cows, and the associated influencing factors, have not been well characterized. Weighted mean differences (WMD) of continuous variables from 14 articles published by March 31, 2025, were pooled by random-effects models using the Stata version 17 to explore the details regarding Arg application in dairy cows.

Our objective was to develop a discrete, monthly Markov-chain model to assess the economic performance and herd dynamics of herd scenarios with varying 21-d pregnancy rates (21-d PR), semen types (conventional vs. sexed and beef semen), and insemination eligibility periods (IEP). We classified the estimated herd 21-d PR as low (20%), below average (25%), average (30%), above average (35%), or high (40%). The semen type scenarios included (1) conventional semen for all inseminations regardless of parity (conventional) and (2) sexed semen inseminations for nulliparous heifers (75%) and for primiparous and secondiparous cows for first and second inseminations, with all remaining inseminations across parities to beef semen (sexed+beef).

α-Amylase–enabled corn (AAC) and ensiling of corn kernels can improve starch digestion, feed efficiency, and N partition into milk of dairy cows. This experiment evaluated the effect of AAC on cows fed finely ground (GRC) or rehydrated and ensiled (REC) corn kernels on the lactational performance, DMI, ruminal fermentation, digestibility, chewing behavior, and N partition of dairy cows. Twenty-four individually fed Holstein cows (37.1 ± 4.8 kg/d milk yield, 143 ± 100 DIM, 633 ± 64 kg body weight), arranged in 4 × 4 Latin squares (with 21-d periods), were assigned to 4 treatment sequences.

Most dairy cows experience some degree of inflammatory activation during the early postpartum period as a normal response to parturition and the initiation of lactation. Excessive inflammation during this time has been associated with various disease states, impaired reproductive success, and decreased productivity, but time points appropriate for measurement of inflammatory status are not well established. Our objective in this exploratory observational cohort study was to evaluate the relationships between inflammatory markers, specifically haptoglobin and serum amyloid A, measured at 2 DIM and important metrics of lactational success including milk yield through 10 wk in lactation, rumination and activity time during the periparturient period, risk of dyscalcemia, and time to herd removal.

The efficacy of 6 binders in sequestering perfluorooctane sulfonic acid (PFOS) under in vitro ruminal conditions was evaluated. Binders, including bentonite, montmorillonite aluminum pillared clay, chitosan, activated charcoal Norit, and cholestyramine resin (CHM), were tested at a dose of 1.8% (wt/wt; fresh basis). The PFOS (%) binding affinity of binders was calculated in relation to the control. A randomized complete block design (n = 4) was used to analyze the data. Only CHM, an anion-exchange resin, demonstrated strong potential to sequester PFOS (=52.5%).

The aim of this study was to test the effect of 3-nitrooxypropanol (3-NOP) on methane emissions, animal performance, milk composition, and rumen fermentation in early lactation dairy cows fed a forage-rich diet. A second objective was to assess the 13C isotopic signature of milk as a potential proxy for methane-emission status. Twenty-seven cows with similar BW and age in early lactation (7–11 DIM) and fed a 75% forage-based diet were selected and distributed to 2 balanced groups in a randomized block design.

The effect of His supplementation on the lactational performance in dairy cows as well as the potential interfering factors have not been well characterized. Nineteen peer-reviewed papers from PubMed, Web of Science, and Google Scholar databases published by December 31, 2024, were pooled to calculate the weighted mean differences (WMD) and CI for continuous variables using a stratified 3-level meta-analysis with a random-effects model. A moderator analysis was used to evaluate the influences of cow breed, lactation stage, dietary MP supply, basal diet type, and other supplements as well as method and dosage of administration on the effects of supplemental His.