Heat stress (HS) can result in decreased production and poor fertility performance in dairy cattle. There is limited understanding of the point at which heat load begins to affect fertility, causing a major challenge for the industry. The temperature-humidity index (THI) is a metric commonly used to represent the realized heat load on livestock, as it incorporates both ambient temperature and humidity percentage. The objectives of this study were to estimate the threshold of THI at which the interval of days from first service to conception (FSTC) begins to increase due to HS, evaluate the effect of estrus synchronization on that threshold, and identify geographic regions of concern for Canadian dairy farming.

Twinning is associated with metabolic and reproductive disorders in dairy cows and health issues in calves, with unavoidable effect on herd profitability. To explore the feasibility of selecting against twinning or stabilizing its occurrence, it is crucial to evaluate the genetic relationship with key production traits to avoid any unintended negative consequences. The aim of the present study was to estimate the genetic and phenotypic correlations of twinning rate (TR) with 305-d milk, protein, and fat yields, and protein and fat percentages in Italian Holstein cows.

Foodborne pathogens, particularly multidrug-resistant (MDR) Staphylococcus aureus, present a substantial threat to public health through the food chain. In this study, Lactiplantibacillus plantarum LP-170 was isolated from camel feces, and its cell-free supernatant (CFS) exhibited remarkable antibacterial activity against both standard S. aureus ATCC 29213 and MDR S. aureus strains isolated from contaminated milk. The CFS of LP-170 demonstrated maximum inhibition zone sizes of 20.21 ± 0.21 mm in agar well diffusion assays.

Escherichia coli in food indicates fecal contamination, and certain strains may compromise food safety, such as diarrheagenic strains (DEC). This study aimed to track the presence of DEC throughout mozzarella production and identify postpasteurization critical control points. The E. coli counts and DEC characterization were performed across different batches of mozzarella, from raw milk to the final 120 d of shelf life. Among the 58 isolates collected from raw milk, 15.52%, 8.62%, and 3.35% were identified as enteropathogenic (EPEC), enteroaggregative (EAEC), and enteroinvasive E.

In Lactococcus lactis (L. lactis), the presence of native plasmids holds significant biological and practical value. They commonly harbor functional genes related to metabolism, antibiotic resistance, bacteriocin synthesis, and stress responses, thereby enabling the strain to adapt to diverse environmental conditions. A comprehensive investigation into the 3 native plasmids in L. lactis C20 was conducted to elucidate their functions, evolutionary origins, and impacts on growth, metabolic activity, enantiomeric purity of L/D-lactate, and nisin biosynthesis.

Milk fat is a major source of dairy farm income and methods to increase milk fat yield are of strong interest to producers and nutritionists. Sodium acetate supplementation increases milk fat in lactating cows, but dietary factors that impact ruminal acetate synthesis may modify the response to acetate supplementation. Our objective was to test the interaction between acetate supplementation and dietary UFA concentration. The hypothesis was that acetate would increase milk fat yield more when supplemented in diets containing high levels of UFA compared with low levels of UFA.

The objective of this study was to examine Ontario dairy veterinarians' perspectives when working with producers on managing and caring for down dairy cows, focusing on protocols, current practices, implementation of best practices, and barriers. A total of 20 one-on-one online interviews with dairy veterinarians were conducted between July to December 2024, lasting a median of 30 min (range: 20–45 min). Veterinarians were asked to share their perspectives on a range of topics related to down cow management, including their experiences advising producers, observations of producer decision making, common care practices, and contextual challenges such as facility design and equipment use.

Adipose tissue remodeling is essential for mammary gland development and functional restoration. The dry period represents a pivotal phase characterized by extensive tissue remodeling as the gland transitions from pregnancy to lactation. However, the morphological and molecular mechanisms underlying mammary adipose tissue remodeling during this stage remain poorly understood. In this study, we investigated adipose remodeling in the mammary gland of dairy goats during this transitional period. An integrative multi-omics approach combining transcriptomics, lipidomics, and metabolomics was employed to comprehensively characterize the molecular changes of mammary tissue.

The high prevalence of diarrhea in calves raises serious welfare concerns and imposes substantial economic losses on dairy farms. Probiotic strains that produce butyric acid may lower diarrhea incidence and improve gut health. This study evaluated the effects of direct-fed Clostridium beijerinckii R8 on growth performance, plasma biochemistry, and fecal microbiota in neonatal calves. Sixty newborn female calves were blocked by birth weight and randomly allocated to 4 treatments: (1) control (0 cfu/d), (2) low dose (1 × 109 cfu/d), (3) medium dose (1 × 1010 cfu/d), and (4) high dose (1 × 1011 cfu/d).

The objective of this study was to investigate mechanisms underlying the relationship between basal diet (BD) composition (grass silage– vs. corn silage–based) and 3-nitrooxypropanol (3-NOP) supplementation, focusing on the rumen microbiome, and gaseous emission and ruminal fermentation dynamics. Eight rumen-fistulated, multiparous Holstein-Friesian dairy cows producing 29.3 ± 8.17 kg/d of milk at 159 ± 82.8 DIM (mean ± SD) at the beginning of the experiment were blocked according to parity, DIM, and milk production, and randomly assigned to a double 4 × 4 Latin square design with 4 treatments.

Mastitis remains a substantial challenge for the dairy industry. Producers strive to maximize dairy cow production, health, and well-being, while also reducing antibiotic usage. Limitations to current mastitis measures have led to the exploration of the use of differential SCC (DSCC). Rather than evaluating the total cell population within milk (i.e., SCC), DSCC focuses on the distribution of individual white blood cell (WBC) types. During an infection, the number of WBC will change dramatically as a result of inflammation.

We investigated associations of early postpartum systemic inflammatory and metabolic markers in Holstein cows with different manifestations of reproductive tract inflammatory disease (RTID). A retrospective case-control study was conducted using data from 1,509 cows in 2 commercial dairy herds in Ontario, Canada. Herds were visited twice weekly and cows were sampled at 2 and 6 ± 2 DIM to measure serum haptoglobin (Hp), total Ca, and nonesterified fatty acids (NEFA); at 5, 8, 11, and 15 ± 2 DIM for blood β-hydroxybutyrate (BHB); and at 21 and 35 ± 3 DIM for serum Hp.

Interactions among metabolic, oxidative, and inflammatory states are expected to influence cow health and physiology during the transition period. However, the interrelation remains to be elucidated. In this study, 66 lactations from 57 individual multiparous Holstein Friesian cows with a complete profile of oxidative and inflammatory status-related variables at both −7 and 21 d relative to calving were involved under similar transition management. Blood samples were collected at −7 (7 d before the expected calving date) and 3, 6, 9, and 21 DIM to analyze metabolic markers, including BHB acid (BHBA), nonesterified fatty acids, and insulin.

A feeding trial was conducted with 60 mid-lactation cows that were, on average, 116 DIM, parity 3.5, and with a fat- and protein-corrected milk (FPCM) yield of 34 kg/d. Cows were blocked based on cow traits and milk performance. Cows in each block were randomly allocated to 1 of 3 treatments that differed by replacement of half of the dietary grass silage component (involving an exchange of 20% of dietary DM). Treatments were a regular high-quality grass silage (positive control; GS-POS), an ensiled press cake obtained from grass biorefinery (GS-PC), or a lower-quality grass silage (negative control; GS-NEG).

Johne's disease (JD) is an infectious bacterial disease (Mycobacterium avium ssp. Paratuberculosis) that primarily affects the intestinal tract and associated lymph nodes of ruminants, especially in cattle. It is both a herd-level problem and an individual animal problem, as much of the infection is subclinical. This disease has a significant impact due to drastic production losses and early culling of animals. Here, we used MALDI-TOF mass spectrometry for diagnostic screening of Johne's disease state from serum samples collected in the panhandle of Texas.

The objective of this study was to identify the differences in the transition period time budget of first-lactation cows that adapt quickly to a free-traffic automatic milking system (AMS) versus those that require more chronic fetching during the adaptation period following calving. A total of 22 primiparous Holstein cows were observed from ∼21 d before calving to 23 DIM, following their adaptation to an AMS. During the prepartum period, heifer time budgets were monitored for rumination, feeding activities, lying behavior, and standing behavior.

Despite the routine use of SCS and differential somatic cell count (DSCC) as indirect udder health indicators, few studies explored how these 2 traits and their interaction can affect milk quality, especially in terms of mineral elements. Therefore, this study investigated the effect of SCS, DSCC, and their interaction on the concentration and daily excretion of major minerals (Ca, Mg, K, S, P, Cl, and Na) in bovine milk. A total of 1,060 Brown Swiss cows from 53 commercial herds in northern Italy were individually sampled over a 14-mo period.

To enhance the performance of CN as a natural emulsifier in complex food systems, this study prepared CN-isomaltooligosaccharide (IMO) conjugates via Maillard reaction under wet-heat conditions, systematically investigating their structural and functional changes. With increasing CN-IMO ratio, the grafting degree first increased and then decreased, reaching a maximum of 36.39% in the CI53 sample. Sodium dodecyl sulfate-PAGE, Fourier-transform infrared spectroscopy, UV-visible spectroscopy, and fluorescence spectroscopy indicated covalent bonding between CN and IMO, accompanied by significant protein conformational rearrangement.

Commercial dairy farms face major challenges in safeguarding animal welfare and overall farm sustainability from environmental heat stressors. As climate change drives increased temperatures in many places, it is essential to predict the potential effects of heat stress on dairy cows to mitigate the adverse impact. This study aimed to develop an eXtreme Gradient Boosting (XGBoost) machine learning model to predict the daily milk production of 3,369 lactating dairy cows under different climatic conditions across 10 different commercial dairy farms in Australia.

This study investigates the functionality of mesoscale whey protein particles (WPP) derived from fiber- and ribbon-shaped whey protein assemblies produced via a liquid antisolvent precipitation-based method. The air-water (A-W) interfacial characteristics, foaming properties, and heat stability of WPP were evaluated and compared with the original whey protein source, whey protein isolate (WPI). Adsorption dynamics and dilatational rheology at the A-W interface were characterized using pendant drop and oscillating drop methods, respectively.