Invited review: Antimicrobial resistance genes in milk—A 10-year systematic review and critical comment. By Sievers et al., page 4508. Acquired antimicrobial resistance (AMR) is programmed by AMR genes, and the occurrence of such AMR genes in milk is frequently investigated. Antimicrobial resistance genes can indicate a risk of treatment failure for the cow, a risk for human health due to consumption, or both. Thus, milk monitoring should place a stronger focus on AMR that are relevant for cattle and human health.

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

The excellent properties of Lactobacillus helveticus KLDS1.8701 (L. helveticus KLDS1.8701) make it a potential auxiliary starter strain. This study aimed to investigate the effects of L. helveticus KLDS1.8701 on yogurt and the mechanisms underlying these effects. The results indicated that L. helveticus KLDS1.8701, when used as an auxiliary starter, significantly shortened fermentation time, improved the textural and rheological properties of yogurt, and enhanced its viscosity and water-holding capacity.

Direct-salted, block Gouda has recently become a popular cheese that is made in the United States, mostly for export purposes. The dairy industry uses 2 types of manufacturing options for this cheese; stirred curd (SC) and milled curd (MC), and we wanted to explore if there were any differences in the properties of cheese made with these 2 different methods. We also investigated 2 options to help extend the performance shelf life and functionality of this direct-salted Gouda cheese: high-pressure processing (HPP) and the use of different storage temperatures.

Reproductive success is an essential component of profitable and sustainable dairy operations. Although selection for production traits such as milk yield has led to a decline in fertility in dairy cattle, strategies including assisted reproductive technologies such as in vitro fertilization and embryo transfer, as well as genomic selection for fertility traits, are being implemented to help mitigate this loss. Previous studies have identified genetic markers associated with fertility traits such as daughter pregnancy rate, conception rate, and interval to first conception.

Maintenance energy requirements for growing dairy heifers have not been experimentally studied in great depth since the mid-1980s, and to our knowledge no direct measurements of maintenance have ever been conducted on growing Jersey heifers. The maintenance energy requirement of growing animals is first fulfilled before energy use for gain. As a result, current estimates of maintenance are needed to effectively model gain. Therefore, the objectives of this study were to first use indirect calorimetry to estimate maintenance energy requirements and fasting heat production (FHP) of growing Jersey heifers, and second to compare net energy for maintenance (NEmaint) via indirect methods of regression from the data associated with metabolizable energy for maintenance (MEmaint) versus that estimated using direct measures fasting heat production.

Bovine respiratory disease (BRD) remains a costly challenge to the dairy industry, as the bacterial complex involved in BRD has shown decreased susceptibility to antimicrobials, exacerbating its effects on animal health, productivity, and recovery. In human medicine, cumulative antimicrobial susceptibility testing (CAST) is used to generate antibiograms that support empirical decision-making for antimicrobial treatment. The goal of this study was to evaluate a CAST framework for BRD in dairy cattle and factors of relevance when analyzing and reporting antibiogram data for on-farm treatment decisions.

The peptide SPAQILQW with potential immunomodulatory activity in casein hydrolysates has been obtained in previous study, but the stability of its activity and key active sites remains to be explored. This study demonstrated that SPAQILQW could promote the proliferation and phagocytic activity of macrophages, increase the expression of key inflammatory mediators and chemokines in macrophages, and possess significant immunomodulatory activity in vitro. The results of an in vitro gastrointestinal protease-mimicking hydrolysis assay and a Caco-2 cell monolayer membrane model demonstrated that SPAQILQW could overcome the hydrolysis by digestive enzymes in the gastrointestinal tract and 10.15 ± 0.08% of it could enter the bloodstream through the intestinal brush border membrane to exert its active effects, including activating macrophages by promoting the expression of chemokines (CXCL1) and TNF-α and NO.

Immune activation and subsequent inflammation lead to difficult transitions from pregnancy to lactation. Whether postpartum hyperketonemia can occur independently of immune activation remains controversial. Our objective was to compare immunometabolic profiles in blood serum from healthy cows, healthy feed-restricted cows, and cows with naturally occurring inflammatory disorders. Multiparous Holsteins (n = 32) were fed a dry period diet until parturition. After parturition, all cows were fed a lactation diet at ad libitum intake until 5 DIM.

The objective of this study was to evaluate the differences in milk production, reproductive performance, and culling associated with antimicrobial therapy and clinical cure of metritis in dairy cows. In this study, data from 2 randomized controlled trials consisting of 900 Holstein cows from 5 dairy farms in California, Florida, and Texas were used. Cows were examined for metritis (fetid, watery, reddish-brownish vaginal discharge; VD) at 4, 7, and 10 DIM (study d 0). Cows diagnosed with metritis (n = 900) were randomly assigned (regardless of fever) to receive ceftiofur (CEF = 457) or to remain untreated (NT = 443).

The outbreak of H5N1 in dairy cattle in United States revealed challenges in identification and management of a novel disease. The virus showed an exceptional ability to spread between farms and among cows within a farm. The impact of the virus on dairy cattle varied from nonclinical to severe clinical signs and death. Many dairy producers did not report clinical signs in their cows or test for the virus. Cats and peridomestic birds on many affected dairies died from viral exposure. Dairy workers showed signs of conjunctivitis, which was confirmed to be due to H5N1.

Interest in nonbovine milk, such as buffalo and camel milk, for human consumption is increasing, yet information on their nutritional quality is limited. This study aimed to investigate the fatty acid profiles of camel and buffalo milk, focusing on how species and seasonal variations affect their nutritional value. Buffalo milk and camel milk samples were collected respectively from the Guangxi Zhuang Autonomous Region and Xinjiang Uyghur Autonomous Region of China over the year. A total of 88 fatty acids (C1–C24) were quantified using GC-MS as part of a comprehensive fatty acidomics approach.

The nutrient consumption patterns of Streptococcus thermophilus F7 under acid stress were investigated in this study. The strain was incubated at 42°C for 16 h in a chemically defined medium with different pH values (6.5, 5.8, and 5.5), and consumption of a variety of nutrients including amino acids, vitamins, purine/pyrimidine bases, and ions was observed. The results showed that Leu was the most consumed amino acid at all pH levels, and the consumption values were 2.5, 3.4, and 4.5 μmol/cfu × 10−5 at pH 6.5, 5.8, and 5.5, respectively.

This study aimed to assess the effectiveness of fatty acid (FA) fingerprinting in distinguishing the geographical origin of milk and linking milk FA profiles with those of forage. A total of 66 bulk-tank milk samples and 66 corresponding forage samples were collected over 3 consecutive days from 22 dairy farms across western, eastern, and southern China. The FA compositions of the samples were analyzed using GC-MS, identifying 81 individual FA. Using orthogonal partial least squares discriminant analysis and significance analysis, we identified significant regional differences in the 35 milk FA.

Little is known about effects of maternal characteristics around gestation in cows on their female offspring in early and later life. The objective of the current study was to investigate the relationship between cow characteristics during the preconception and gestation period, and the BW, energy metabolism, hormones, immune function, liver enzymes, and milk variables of their female offspring from birth until the first 100 d after their first calving. Holstein-Friesian dairy cows (n = 154) were blocked according to parity, milk yield, and SCC, and randomly assigned to a voluntary waiting period (VWP) of 50, 125, or 200 d.

Eating and rumination activities influence rumen environmental characteristics, such as volume, digesta particle size, microbial activity, and the acidity of rumen fluid. The aim of this study was to update an existing mechanistic, steady-state rumen model to simulate diurnal patterns of rumen functioning, contributing to a better understanding of rumen metabolism. Daily patterns of eating behavior were defined as model inputs based on meal characteristics and feeding regimens. Mechanisms controlling the dynamics of rumen content and fluid volume, particle diminution of roughage, rumination behavior, lactic acid metabolism, and rumen fluid pH were mathematically represented.

Dairy cows' productive performance is influenced by various factors, including nutrition, housing comfort, and weather conditions during grazing. In classic confinement systems, animal comfort is typically ensured through ventilation and sprinkling features. However, in mixed feeding systems, controlling environmental conditions at the supplementation site is less common. The present 2-yr study evaluated 2 lactations and 2 calving seasons (autumn and spring) with 3 treatments that combined 2 housing systems (compost barn [CB] or outdoor soil-bedded pens with shade structures [OD]) and 2 feeding strategies with varying proportions of grazing (TMR with no grazing and one-session grazing supplemented with mixed ration [GRZ]).

Rumination time (RT) in dairy cattle is a crucial indicator of health, production, reproduction, and greenhouse gas emissions. With moderate heritability estimates for RT, there is potential for further analyses regarding the genetic architecture of the trait. To identify genomic regions associated with RT, we conducted a GWAS on SNPs in a cohort of 452 mid-first-lactation Canadian Holstein cows, followed by the annotation of genes and enrichment analyses of quantitative trait loci (QTL). Animals were genotyped using a medium-density SNP panel (50 K).