Apparent trace metal absorption and tissue retention upon incremental levels of supplemental Zn, Cu, and Mn were studied in growing cattle. A total of 60 Holstein bulls (age = 246 ± 5 d, BW = 329 ± 26 kg) were enrolled for the study and fed for 6 to 9 wk a diet consisting of barley straw (15%), molasses (10%), and a pelleted concentrate (75%; 78, 15, and 91 mg/kg DM for Zn, Cu, and Mn, respectively). Thereafter, 20 bulls were randomly selected and slaughtered for determination of a baseline tissue trace metal composition.

This study developed a novel analytical method integrating liquid-liquid extraction with solid-phase extraction for simultaneous detection of oxyclozanide (OXY) and levamisole hydrochloride (LMS) residues in milk using ultra-high-performance liquid chromatography tandem MS (UPLC-MS/MS). Method validation demonstrated exceptional sensitivity with detection limits of 1.00 ng/mL and quantitation limits of 3.00 ng/mL for both analytes. Low matrix effects (CV <8.00%) and satisfactory recoveries (OXY: 84.00%–108.77%, relative SD [RSD]: 2.20%–8.00%; LMS: 89.50%–119.60%, RSD: 2.10%–8.36%) were achieved across multiple validation parameters, while sample stability remained consistent under varied processing conditions (CV <10.00%).

Colostrum is the first secretion produced by the mammary gland after calving, providing essential macronutrients and micronutrients to newborns. Monitoring elemental concentrations in bovine colostrum (BC) is crucial, as it serves for the physiological development and health of the neonates. Current gold-standard methods to determine elemental composition of BC are inductively coupled plasma optical-emission spectrometry or inductively coupled plasma MS. These techniques, however, are time-consuming, expensive, labor-intensive, and destructive, and they require sample preparation such as chemical matrix decomposition.

We evaluated the effects of insufficient (WET) or extended (CUR) wilting on the concentration of phytoestrogens, nutritional value, microbial populations, in vitro ruminal methane emissions, and in situ degradability of red clover silage (DM: 294 and 453 g/kg) and hay (DM: 651 and 891 g/kg, respectively) across storage stages. Measurements were taken at the start of storage (STRT), after 14 d (early stage of storage), and once storage processes had stabilized for hay and silage (50 and 78 d, respectively; late stage).

This experiment investigated the variability and repeatability of residual feed intake (RFI) in growing and lactating dairy goats, aiming to assess its potential as a selection tool for feed efficiency. During the growth phase, 60 5-mo-old Saanen doelings were grouped based on genetic potential for milk production: high-index (HI; n = 30) and low-index (LI; n = 30) doelings were used. During the lactation phase, 53 early-lactation does, also selected for HI and LI, were used. Of these 53 lactating does, 28 were from the growth phase to investigate the repeatability of RFI rankings.

We investigated the effects of feeding incremental amounts (0%, 3%, and 6% of diet DM) of the red seaweed Chondrus crispus on DMI, milk yield and milk components, enteric CH4 emissions, nutrient utilization, ruminal fermentation and microbiota relative abundance, and I metabolism in dairy cows. Eighteen organic certified Jersey cows (12 multiparous and 6 primiparous) averaging (mean ± SD) 94 ± 45 DIM, 22 ± 5.2 kg of milk/d, and 485 ± 54 kg of BW in the beginning of the study were used in a replicated Latin square design with three 24-d periods (14 d for diet adaptation and 10 d for data and sample collection).

Beets have a high sugar content, which is primarily fermented to ethanol during ensiling. This study investigated the effects of feeding diets with sugar-rich beets or ethanol-rich beet silage to lactating dairy cows on postabsorptive ethanol metabolism, enteric gas emissions, and microbial protein synthesis. Beets were washed, crushed, and stored in daily portions either as is (frozen at −20°C for preservation) or ensiled in barrels. Four rumen-cannulated Danish Holstein cows were used in a replicated (one complete and one incomplete) 3 × 3 Latin square design, with 3 treatments and three 21-d periods.

This study used Rhodobacter sphaeroides protein (RSP) as an innovative dietary protein source for Holstein dairy calves. We investigated its effects on growth performance, nutrient digestibility, rumen fermentation, and serum metabolites, antioxidants, immunoglobulins, and inflammatory factors. A total of 45 female Holstein calves (36.54 ± 1.68 kg of BW; 1 d of age) were randomly assigned to 3 treatment groups and fed either a control diet (CON) or diets with 5.89% or 11.49% RSP (RS1 and RS2, respectively) on a diet DM basis for 14 wk.

Intramammary infections occur commonly in dairy heifers; however, there is a lack of understanding regarding the onset and occurrence of IMI in nulliparous heifers during varying stages of development. The objectives of this study were to (1) determine at what age or stage of gestation heifer mammary samples are culture positive, (2) compare the bacterial genera and species found among sample types, (3) assess the potential of using a needle-based mammary gland sampling technique in heifers, and (4) use novel, multimethod diagnostic criteria to more comprehensively define heifer IMI (hIMI) occurrence.

We hypothesized that prepartum supplementation of fat in a short dry period would improve postpartum energy balance (EB) and produce milk comparable to the traditional dry period. The objective was to investigate the effect of dry period length and prepartum fat supplementation on DMI, EB, BCS, milk yield, and uterine health. The experiment was a randomized complete block design. Holstein cows were blocked by parity and previous lactation milk yield on 207 ± 3 d of gestation. The experiment was conducted in batches: in the first batch, cows were assigned randomly to either a traditional 60-d dry period (TDP; n = 14) or a short 30-d dry period (SDP; n = 14); in the second batch, cows were assigned to TDP (n = 08), SDP (n = 09), or SDP with fat supplementation (SDP-F; n = 08).

Low reticuloruminal pH (rpH) for a prolonged period could lead to SARA. This disease negatively affects cow health and is associated with monetary losses for the dairy industry. The aim of this study was to predict rpH and SARA separately using different machine learning (ML) models applied to Fourier transform infrared spectroscopy (FTIR) spectra obtained from routine DHI milk analysis of individual cows. A total of 107 primiparous and multiparous Holstein cows were selected from 12 commercial farms in Québec, Canada, and their rpH was continuously monitored for 150 d using wireless boluses.

Invited review: Interplay of rumen microbiome and the cattle host in modulating feed efficiency and methane emissions. By Badhan et al., page 5489. The rumen microbiome plays a pivotal role in feed efficiency by influencing the conversion of plant biomass to fermentation products and microbial protein usable by the host. Evidence suggests that rumen microbial diversity and functionality are tightly linked to feed efficiency phenotype. However, the relationship between microbial diversity and feed efficiency is not straightforward, as host genetics and physiological traits shape the composition and interconnectivity of the rumen microbiome, affecting the efficiency of nutrient utilization and CH4 emissions.

Body condition dynamics are known to affect the different steps of reproduction in cattle (cyclicity, estrus expression, fertilization, embryo development). This has led to a widespread idea that there is an ideal-target optimal body condition, but no clear profile has yet been identified. Here we investigated the relationships between BCS profiles and reproductive performance in dairy cows. Data were from Holstein or Normande herds in 6 French experimental farms. In the Holstein breed, we discriminated 4 BCS profiles based on combining BCS at calving (Low indicates BCS ∼2.6 points at calving; High indicates BCS ∼3.3 points at calving) with BCS loss after calving (Moderate [M] indicates BCS loss of ≤1.0 points at calving; Severe [S] indicates BCS loss of >1.0 points at calving).

In this article, some values in Table 3 and Table 4 were incorrect.

Emissions per tonne of excreted manure for the manure system (barn, storage, and land application) range from 3.0 to 4.4 kg of NH3 for conventional farms, 3.5 to 4.4 kg of NH3 for organic farms, and 3.4 to 3.9 kg of NH3 for grazing farms.

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes.

Dairy cattle can succumb to illnesses at any given time. However, most diseases take place around 2 clusters: (1) the time around calving, commonly referred to as the periparturient period, for metabolic and infectious diseases (e.g., hyperketonemia, dyscalcemia, mastitis, metritis, etc.) and (2) the first few weeks of life, referred to as the neonatal period, for diseases of calves (e.g., diarrhea or respiratory disease). Although the pathogenesis of these diseases is different, they share the feature that animals exhibit dysfunctional immune responses.

Certain cheeses (e.g., Mozzarella) can be stretched and molded when heated. If a cheese can stretch, perhaps its properties can also be modified to allow it to expand during microwave heating and drying to produce a crunchy, shelf-stable snack. To investigate this concept, we made a model system similar to pasteurized process cheese product (PPCP) that allowed us to vary 2 key parameters; protein (PN) content and the pH value, and to limit the meltability due to the high levels of intact casein.