The 50 most-cited articles in Journal of Dairy Science, 2023

Heat stress compromises dairy production by decreasing feed intake and milk yield, and it may also alter milk composition and feed efficiency. However, little information is available for evaluating such effects across different levels of heat stress and cows enrolled in heat stress studies. The objectives of this study were to evaluate the effects of heat stress on dry matter intake (DMI), energy-corrected milk (ECM), milk composition, and feed efficiency (kg ECM/kg DMI) and to investigate the relationship between such effects and heat stress intervention and animal characteristics by using meta-analytical approaches. Data from 31 studies (34 trials) fulfilled the inclusion criteria and were used for analysis. Results showed that heat stress decreased DMI, ECM, and milk protein concentration, but did not alter milk fat concentration or feed efficiency. Meta-regression confirmed that such reductions in DMI and ECM were significantly associated with increasing temperature-humidity index (THI). Over the period of heat stress, for each unit increase in THI, DMI and ECM decreased by…

Raw milk typically has little bacterial contamination as it leaves the udder of the animal; however, through a variety of pathways, it can become contaminated with bacteria originating from environmental sources, the cow herself, and contact with contaminated equipment. Although the types of bacteria found in raw milk are very diverse, select groups are particularly important from the perspective of finished product quality. In particular, psychrophilic and psychrotolerant bacteria that grow quickly at low temperatures (e.g., species in the genus Pseudomonas and the family Enterobacteriaceae) and produce heat-stable enzymes, and sporeforming bacteria that survive processing hurdles in spore form, are the 2 primary groups of bacteria related to effects on processed dairy products. Understanding factors leading to the presence of these important bacterial groups in raw milk is key to reducing their influence on processed dairy product quality. Here we examine the raw milk microbiological parameters used in the contemporary dairy industry for their utility in identifying raw milk…

Three modifications (pH shift, ultrasound, combined pH shift and ultrasound) induced alterations in pure whey protein isolate (WPI), pea protein isolate (PPI), and mixed whey and pea protein (WPI-PPI) were investigated. The processing effect was related to the protein type and technique used. Solubility of WPI remained unchanged by various treatments. Particle size was enlarged by pH shift while reduced by ultrasound and combined approach. All methods exposed more surface hydrophobic groups on WPI, while pH shift and joint processing was detrimental to its emulsifying activity. The PPI and mixture exhibited similar responses toward the modifications. Solubility of PPI and the blend enhanced in the sequence of pH shift and ultrasound > ultrasound > pH shift. Individual approach expanded while co-handling diminished the particle diameter. Treatments also caused more disclosure of hydrophobic regions in PPI and WPI-PPI and emulsifying activity was ameliorated in the order of pH shift and ultrasound > ultrasound > pH shift.

Treatment of clinical mastitis (CM) and use of antimicrobials for dry cow therapy are responsible for the majority of animal-defined daily doses of antimicrobial use (AMU) on dairy farms. However, advancements made in the last decade have enabled excluding nonsevere CM cases from antimicrobial treatment that have a high probability of cure without antimicrobials (no bacterial causes or gram-negative, excluding Klebsiella spp.) and cases with a low bacteriological cure rate (chronic cases). These advancements include availability of rapid diagnostic tests and improved udder health management practices, which reduced the incidence and infection pressure of contagious CM pathogens. This review informed an evidence-based protocol for selective CM treatment decisions based on a combination of rapid diagnostic test results, review of somatic cell count and CM records, and elucidated consequences in terms of udder health, AMU, and farm economics. Relatively fast identification of the causative agent is the most important factor in selective CM treatment protocols. Many reported studies did…

This study aimed to investigate the symbiosis between Streptococcus thermophilus CICC 6038 and Lactobacillus delbrueckii ssp. bulgaricus CICC 6047. In addition, the effect of their different inoculum ratios was determined, and comparison experiments of fermentation characteristics and storage stability of milk fermented by their monocultures and cocultures at optimal inoculum ratio were performed. We found the time to obtain pH 4.6 and ΔpH during storage varied among 6 inoculum ratios (1:1, 2:1, 10:1, 19:1, 50:1, 100:1). By the statistical model to evaluate the optimal ratio, the ratio of 19:1 was selected, which exhibited high acidification rate and low postacidification with pH values remaining between 4.2 and 4.4 after a 50-d storage. Among the 3 groups included in our analyses (i.e., the monocultures of S. thermophilus CICC 6038 [St] and Lb. bulgaricus CICC 6047 [Lb] and their cocultures [St+Lb] at 19:1), the coculture group showed higher acidification activity, improved rheological properties, richer typical volatile compounds, more desirable sensor quality after the…

Heat stress implies unfavorable effects on primary and functional traits in dairy cattle and, in consequence, on the profitability of the whole production system. The increasing number of days with extreme hot temperatures suggests that it is imperative to detect the heat stress status of animals based on adequate measures. However, confirming the heat stress status of an individual is still challenging, and, in consequence, the identification of novel heat stress biomarkers, including molecular biomarkers, remains a very relevant issue. Currently, it is known that heat stress seems to have unfavorable effects on immune system mechanisms, but this information is of limited use in the context of heat stress phenotyping. In addition, there is a lack of knowledge addressing the molecular mechanisms linking the relevant genes to the observed phenotype. In this review, we explored the potential molecular mechanisms explaining how heat stress affects the immune system and, therefore, increases the occurrence of immune-related diseases in cattle. In this regard, 2 relatively opposite…

Flavor sensation is one of the most prevalent characteristics of food industries and an important consumer preference regulator of dairy products. So far, many volatile compounds have been identified, and their molecular mechanisms conferring overall flavor formation have been reported extensively. However, little is known about the critical flavor compound of a specific sensory experience in terms of oxidized off-flavor perception. Therefore, the present study aimed to compare the variation in sensory qualities and volatile flavors in full-fat UHT milk (FFM) and low-fat UHT milk (LFM) samples under different natural storage conditions (0, 4, 18, 25, 30, or 37°C for 15 and 30 d) and determine the main component causing flavor deterioration in the FFM and LFM samples using sensory evaluation, electronic nose, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). In addition, the Pearson correlation between the volatile flavor components and oxidative off-flavors was analyzed and validated by sensory reconstitution studies. Compared with the…

Milk is an important food of the daily diet. Many countries include it in their dietary recommendations due to its content in several important nutrients that exert beneficial effects on human health. Human milk is a newborn's first food and plays an important role in the growth, development, and future health of every individual. Cow milk is the type of milk most consumed in the world. However, its relatively high content of saturated fats raises concerns about potential adverse effects on human health, although epidemiological studies have disproved this association. Indeed, dairy consumption appear to be linked to a lower risk of mortality and major cardiovascular disease events. In the last few years many researchers have begun to focus their attention on both the production and quality of cow milk as well as the analysis of milk from other animal species to evaluate their effect on human health. The need to investigate the composition and metabolic effects of milk from other animal species arises from the adverse reactions of individuals in several groups to certain components…

The objective of the present study was to investigate the effect of individual and combined use of dietary fat, nitrate and 3-nitrooxypropanol (3-NOP) on dairy cows' enteric methane (CH 4 ) emission and production performance. Twenty-four primiparous and 24 multiparous Danish Holstein cows (111 ± 44.6 d in milk; mean ± SD) were included in an incomplete 8 × 8 Latin square design with 6 21 d periods. Dietary treatments were organized in a 2 × 2 × 2 factorial arrangement aiming for 2 levels of FAT (30 or 63 g crude fat/kg of DM; LF or HF, respectively), 2 levels of NITRATE (0 or 10 g nitrate/kg of DM; UREA or NIT, respectively) and 2 levels of 3-NOP (0 or 80 mg/kg of DM; BLANK or NOP, respectively). Treatments were included in ad libitum fed partial mixed rations in bins that automatically measured feed intake and eating behavior. Additional concentrate was offered as bait in GreenFeed units used for measurement of gas emission. For total DM intake (DMI), a FAT × NITRATE interaction showed that DMI, across parities and levels of 3-NOP, was unaffected by separate fat supplementation,…

Considering the increasing challenges imposed by climate change and the need to improve animal welfare, breeding more resilient animals capable of better coping with environmental disturbances is of paramount importance. In dairy cattle, resilience can be evaluated by measuring the longitudinal occurrences of abnormal daily milk yield throughout lactation. Aiming to estimate genetic parameters for dairy cattle resilience, we collected 5,643,193 daily milk yield records on automatic milking systems (milking robots) and milking parlors across 21,350 lactations 1 to 3 of 11,787 North American Holstein cows. All cows were genotyped with 62,029 SNPs. After determining the best fitting models for each of the 3 lactations, daily milk yield residuals were used to derive 4 resilience indicators: weighted occurrence frequency of yield perturbations (wfPert), accumulated milk losses of yield perturbations (dPert), and log-transformed variance (LnVar) and lag-1 autocorrelation (r auto ) of daily yield residuals. The indicator LnVar presented the highest heritability estimates (±standard error),…

This experiment was designed to investigate the relation of high and low methane-yield phenotypes with body weight (BW), dry matter intake (DMI), lactation performance, enteric CH 4 emissions, and rumen fermentation parameters in lactating dairy cows. A total of 130 multi- and primiparous Holstein cows were screened for enteric CH 4 emissions using the GreenFeed system (C-Lock Inc.). Out of these 130 cows, 5 were identified as phenotypically high (HM) and 5 as phenotypically low (LM) CH 4 emitters. Cows in the LM group had lower daily enteric CH 4 emissions than cows in the HM group (on average 346 vs. 439 g/d, respectively), lower CH 4 yield (15.5 vs. 20.4 g of CH 4 /kg of DMI), and CH 4 intensity (13.2 vs. 17.0 g of CH 4 / kg of energy-corrected milk yield). Enteric emissions of CO 2 and H 2 did not differ between HM and LM cows. These 10 cows were blocked by parity, days in milk, and milk production, and were used in a 5-wk randomized complete block design experiment. Milk composition, production, and BW were also not different between LM and HM cows. The concentration of total…

Automatic respiration monitoring of dairy cows in modern farming not only helps to reduce manual labor but also increases the automation of health assessment. It is common for cows to congregate on farms, which poses a challenge for manual observation of cow status because they physically occlude each other. In this study, we propose a method that can monitor the respiratory behavior of multiple cows. Initially, 4,000 manually labeled images were used to fine-tune the YOLACT (You Only Look At CoefficienTs) model for recognition and segmentation of multiple cows. Respiratory behavior in the resting state could better reflect their health status. Then, the specific resting states (lying resting, standing resting) of different cows were identified by fusing the convolutional neural network and bidirectional long and short-term memory algorithms. Finally, the corresponding detection algorithms (lying and standing resting) were used for respiratory behavior monitoring. The test results of 60 videos containing different interference factors indicated that the accuracy of respiratory…

Precision livestock farming (PLF) technologies have been widely promoted as important tools to improve the sustainability of dairy systems due to perceived economic, social, and environmental benefits. However, there is still limited information about the level of adoption of PLF technologies (percentage of farms with a PLF technology) and the factors (farm and farmer characteristics) associated with PLF technology adoption in pasture-based dairy systems. The current research aimed to address this knowledge gap by using a representative survey of Irish pasture-based dairy farms from 2018. First, we established the levels of adoption of 9 PLF technologies (individual cow activity sensors, rising plate meters, automatic washers, automatic cluster removers, automatic calf feeders, automatic parlor feeders, automatic drafting gates, milk meters, and a grassland management decision-support tool) and grouped them into 4 PLF technology clusters according to the level of association with each other and the area of dairy farm management in which they are used. The PLF technology clusters…

The composition of seasonal pasture-produced milk is influenced by stage of lactation, animal genetics, and nutrition, which affects milk nutritional profile and processing characteristics. The objective was to study the effect of lactation stage (early, mid, and late lactation) and diet on milk composition in an Irish spring calving dairy research herd from 2012 to 2020 using principal component and predictive analytics. Crude protein, casein, fat, and solids increased from 2012 to 2020, whereas lactose concentration peaked in 2017, then decreased. Based on seasonal data from 2013 to 2016, forecasting models were successfully created to predict milk composition for 2017 to 2020. The diet of cows in this study is dependent upon grass growth rates across the milk production season, which in turn, are influenced by weather patterns, whereby extreme weather conditions (rainfall and temperature) were correlated with decreasing grass growth and increasing nonprotein nitrogen levels in milk. The study demonstrates a significant change in milk composition since 2012 and highlights the…

Our aim was to review feed additives that have a potential ruminal mechanism of action when fed to dairy cattle. We discuss how additives can influence ruminal fermentation stoichiometry through electron transfer mechanisms, particularly the production and usage of dihydrogen. Lactate accumulation should be avoided, especially when acidogenic conditions suppress ruminal neutral detergent fiber digestibility or lead to subclinical acidosis. Yeast products and other probiotics are purported to influence lactate uptake, but growing evidence also supports that yeast products influence expression of gut epithelial genes promoting barrier function and resulting inflammatory responses by the host to various stresses. We also have summarized methane-suppressing additives for potential usage in dairy rations. We focused on those with potential to decrease methane production without decreasing fiber digestibility or milk production. We identified some mitigating factors that need to be addressed more fully in future research. Growth factors such as branched-chain volatile fatty acids also are…

The aim of this systematic review was to summarize the literature assessing the effects of milk feeding practices on behavior, health, and performance on dairy calves. Peer-reviewed, published articles, written in English, directly comparing the effects of milk allowance, milk feeding methods, or milk feeding frequency on dairy calves were eligible for inclusion. Outcome measures could include sucking behavior, sucking on a teat (nutritive sucking, non-nutritive sucking on a teat), abnormal sucking behavior (non-nutritive sucking on pen fixtures, other oral behaviors, or cross-sucking), signs of hunger (vocalizations or unrewarded visits at the milk feeder), activity (lying time or locomotor play), feeding behavior (milk intake, starter intake, milk meal duration, or starter meal duration), growth (body weight or average daily gain), and health (occurrence of diarrhea, respiratory disease, or mortality). We conducted 2 targeted searches using Web of Science and PubMed to identify key literature. The resulting articles underwent a 2-step screening process. This process resulted in a…

This study aimed to evaluate the effects of added jujube polysaccharide (JP) and Lycium barbarum polysaccharide (LBP) on the texture, rheological properties, and microstructure of goat milk cheese. Seven groups of fresh goat milk cheese were produced with 4 levels (0, 0.2, 0.6, and 1%, wt/wt) of JP and LBP. The goat milk cheese containing 1% JP showed the highest water-holding capacity, hardness, and the strongest rheological properties by creating a denser and more stable casein network structure. In addition, the yield of goat milk cheese was substantially improved as a result of JP incorporation. Cheeses containing LBP expressed lower fat content, higher moisture, and softer texture compared with the control cheese. Fourier-transform infrared spectroscopy and low-field nuclear magnetic resonance analysis demonstrated that the addition of JP improved the stability of the secondary protein structure in cheese and significantly enhanced the binding capacity of the casein matrix to water molecules due to strengthened intermolecular interactions. The current research demonstrated the…

The adoption of preventive management decisions is crucial to dealing with metabolic impairments in dairy cattle. Various serum metabolites are known to be useful indicators of the health status of cows. In this study, we used milk Fourier-transform mid-infrared (FTIR) spectra and various machine learning (ML) algorithms to develop prediction equations for a panel of 29 blood metabolites, including those related to energy metabolism, liver function/hepatic damage, oxidative stress, inflammation/innate immunity, and minerals. For most traits, the data set comprised observations from 1,204 Holstein-Friesian dairy cows belonging to 5 herds. An exception was represented by β-hydroxybutyrate prediction, which contained observations from 2,701 multibreed cows pertaining to 33 herds. The best predictive model was developed using an automatic ML algorithm that tested various methods, including elastic net, distributed random forest, gradient boosting machine, artificial neural network, and stacking ensemble. These ML predictions were compared with partial least squares regression, the most…

Mammalian colostrum, known as "liquid gold," is considered a valuable source of essential nutrients, growth factors, probiotics, prebiotics, antibodies, and other bioactive compounds. Precisely for this reason, bovine colostrum (BC) is an emerging ingredient for the feed, food, and pharmaceutical industries, being nowadays commercially available in a variety of forms in several countries. Moreover, quite a large number of functional foods and supplements for athletes, human medicines, pet nutrition plans, and complementary feed for some livestock categories, such as piglets and calves, contain BC. The amount of BC yielded by a cow after calving represents approximately 0.5% of the yearly output in dairy breeds. For its nutritional properties and low availability, BC is characterized by a greater market value and an increasing demand compared with other by-products of the dairy sector. However, information regarding the market size of BC for the food and pharmaceutical industries, as well as future developments and perspectives, is scarcely available in the scientific literature.…

Corrected milk equations were developed in attempts to bring milk weights to a standardized basis for comparison by expressing the weight and composition of milk as corrected to the energy content of milk of a specific composition. Expressed as milk weights familiar on farm and in commerce, this approach integrates energy contributions of the dissimilar components to make the mass units more comparable. Such values are applied in evaluating feed efficiency, lactation performance, and global milk production, as functional units for lifecycle assessments, and in translation of research results. Corrected milk equations are derived from equations relating milk gross energy to milk composition. First, a milk energy equation is used to calculate the energy value of the milk composition to correct to (e.g., 0.695 Mcal/kg for milk with 3.5% fat, 3.05% true protein, and 4.85% lactose). That energy value is divided into the energy equation to give the corrected milk equation. Confusion has arisen, as different equations purport to correct to the same milk composition; their differences are…

Long-term feeding of a high-concentrate diet can induce subacute ruminal acidosis (SARA) in ruminants, which further leads to systemic inflammatory response. However, few studies have examined the effects of feeding a high-concentrate diet on the hindgut of ruminants. The purpose of this study was to investigate the effects of a high-concentrate diet on the composition of gut microbiota in colonic contents, inflammatory response, and barrier damage in the colon tissue of ruminants. A total of 12 healthy multiparous lactating Hu sheep were randomly allotted into the following 2 groups: a high-concentrate (HC) group (concentrate:forage = 7:3) and a low-concentrate (LC) group (concentrate:forage = 3:7). All sheep were fitted with ruminal fistulas. The formal feeding experiment lasted for 8 wk. After the feeding experiment, rumen fluid, portal vein blood, hepatic vein blood, colonic contents, and colon tissue samples were collected. The results showed that feeding the HC diet induced SARA in Hu sheep and significantly reduced pH in the colonic contents. The abundances of Firmicutes,…

Genotype data from dairy cattle selection programs have greatly facilitated GWAS to identify variants related to economic traits. Results can enhance the accuracy of genomic prediction, analyze more complex models that go beyond additive effects, elucidate the genetic architecture of a trait, and finally, decipher the underlying biology of traits. The entire process, comprising data generation, quality control, statistical analyses, interpretation of association results, and linking results to biology should be designed and executed to minimize the generation of false-positive and false-negative associations and misleading links to biological processes. This review aims to provide general guidelines for data analysis that address data quality control, association tests, adjustment for population stratification, and significance evaluation to improve the reliability of conclusions. We also provide guidance on post-GWAS strategy and the interpretation of results. These guidelines are tailored to dairy cattle, which are characterized by long-range linkage disequilibrium, large half-sib…

Genetic selection to reduce methane (CH 4 ) emissions from dairy cows is an attractive means of reducing the impact of agricultural production on climate change. In this study, we investigated the feasibility of such an approach by characterizing the interactions between CH 4 and several traits of interest in dairy cows. We measured CH 4 , dry matter intake (DMI), fat- and protein-corrected milk (FPCM), body weight (BW), and body condition score (BCS) from 107 first- and second-parity Holstein cows from December 2019 to November 2021. Methane emissions were measured using a GreenFeed device and expressed in terms of production (MeP, in g/d), yield (MeY, in g/kg DMI), and intensity (MeI, in g/kg FPCM). Because of the limited number of cows, only animal parameters were estimated. Both MeP and MeI were moderately repeatable (>0.45), whereas MeY presented low repeatability, especially in early lactation. Mid lactation was the most stable and representative period of CH 4 emissions throughout lactation, with animal correlations above 0.9. The average animal correlations of MeP with DMI,…

Foot disorders are costly health disorders in dairy farms, and their prevalence is related to several factors such as breed, nutrition, and farmer's management strategy. Very few modeling approaches have considered the dynamics of foot disorders and their interaction with farm management strategies within a holistic farm simulation model. The aim of this study was to estimate the cost of foot disorders in dairy herds by simulating strategies for managing lameness. A dynamic and stochastic simulation model (DairyHealthSim) was used to simulate the herd dynamics, reproduction management, and health events. A specific module was built for lameness and related herd-level management strategies. Foot disorder occurrences were simulated with a base risk for each etiology [digital dermatitis (DD), interdigital dermatitis, interdigital phlegmon, sole ulcer (SU), white line disease (WLD)]. Two state machines were implemented in the model: the first was related to the disease-induced lameness score (from 1 to 5), and the second concerned DD-state transitions. A total of 880 simulations were…

Oxidative stress is the imbalanced redox status between oxidants production and their scavengers leading to intestinal physiological dysfunction. However, the role of systemic and local oxidative status during neonatal calf diarrhea is not known. This study assessed systemic (serum) and local (fecal) oxidative status when calves either naturally developed diarrhea or naturally recovered. Healthy calves were enrolled in the study at age of d 18 and their health status were monitored from the enrollment. Based on their enteric health status on D21 and D28, calves were grouped as continuous diarrhea from D21 to D28 (DD group, n=14), diarrhea at D21 but recovered at D28 (DH group, n=19), healthy at D21 but developed diarrhea at D28 (HD group, n=15), and healthy throughout the study (HH group, n=16). Serum and fecal samples were collected at D21 and D28 from all calves in the morning 2 h after feeding. Dynamics of oxidative stress indicators including reactive oxygen species (ROS), malondialdehyde (MDA), H 2 O 2 , 8-hydroxylated deoxyguanosine (8-OHDG), glutathione peroxidase (GPX),…

The objective of this study was to examine the impact of increasing proportions of grazed pasture in the diet on the composition, quality, and functionality of bovine milk across a full lactation. Fifty-four spring-calving cows were randomly assigned to 1 of 3 groups (n = 18), blocked on the basis of mean calving date (February 15, 2020 ± 0.8 d), pre-experimental daily milk yield (24.70 ± 3.70 kg), milk solids yield (2.30 ± 0.27 kg), lactation number (3.10 ± 0.13), and economic breeding index (182 ± 19). Raw milk samples were obtained weekly from each group between March and November 2020. Group 1 (GRS) consumed perennial ryegrass and was supplemented with 5% concentrates (dry matter basis); group 2 was maintained indoors and consumed a total mixed ration (TMR) diet consisting of maize silage, grass silage, and concentrates; and group 3 consumed a partial mixed ration diet (PMR), rotating between perennial ryegrass during the day and indoor TMR feeding at night. Raw milk samples consisted of a pooled morning and evening milking and were analyzed for gross composition, free amino…

Lameness and leg injuries are both painful and prevalent across the dairy industry, and are a major welfare concern. There has been a considerable amount of research focused on investigating the risk factors associated with lameness and injuries and how they might be prevented and treated. The objectives of this narrative review were to summarize herd-level prevalence estimates, risk factors, strategies for prevention, control, and treatment of these conditions, and the barriers to best practice adoption for lameness and injuries on dairy farms. There is a relatively high within-herd prevalence of lameness on dairy farms globally, with a recent systematic review estimating the mean prevalence at 22.8%. Similarly, there is a relatively high prevalence of hock injuries, with within-herd estimates ranging from 12% to 81% of cows affected. Knee and neck injuries have been reported to be less common, with 6% to 43% and 1% to 33%, respectively. Numerous risk factors have been associated with the incidence of lameness, notably housing (e.g., access to pasture, bedding depth, bedding type,…

The use of qualitative research in dairy science has increased considerably in recent years, providing the opportunity to inform research and practice. This review aims to enhance the accessibility of qualitative research among a range of audiences and specifically: (1) provide an overview of what qualitative research is and the value it can bring to scientific inquiries in the dairy context, (2) illustrate the emergence of qualitative dairy science research in the past 15 to 20 years, (3) outline the role of the researcher and key philosophical assumptions underlying qualitative research, (4) describe qualitative research approaches and methods used in dairy science research, and (5) highlight key aspects of qualitative inquiry used to ensure research trustworthiness. Qualitative approaches in dairy science enable researchers to understand myriad topics including stakeholder relationships, decision-making, and behaviors regarding dairy cattle management, animal welfare, and disease prevention and control measures. Approaches that were used often for qualitative data collection were…

Subclinical mastitis in cows affects their health, well-being, longevity, and performance, leading to reduced productivity and profit. Early prediction of subclinical mastitis can enable dairy farmers to perform interventions to mitigate its effect. The present study investigated how well predictive models built using machine learning techniques can detect subclinical mastitis up to 7 d before its occurrence. The data set used consisted of 1,346,207 milk-day (i.e., a day when milk was collected on both morning and evening) records spanning 9 yr from 2,389 cows producing on 7 Irish research farms. Individual cow composite milk yield and maximum milk flow were available twice daily, whereas milk composition (i.e., fat, lactose, protein) and somatic cell count (SCC) were collected once per week. Other features describing parity, calving dates, predicted transmitting ability for SCC, body weight, and history of subclinical mastitis were also available. The results of the study showed that a gradient boosting machine model trained to predict the onset of subclinical mastitis 7 d before a…

To reduce methane (CH 4 ) emissions of dairy cows by animal breeding, CH 4 measurements have to be recorded on thousands of individual cows. Currently, several techniques are used to phenotype cows for CH 4 , differing in costs and applicability. However, there is uncertainty about the agreement between techniques. To judge the similarity and repeatability between measurements of different recording techniques, the repeatability, heritability, and genetic correlation are useful metrics. Therefore, our objective was to estimate (1) the repeatability and heritability for CH 4 and carbon dioxide production recorded by GreenFeed (GF) and for CH 4 and carbon dioxide concentration measured by cost-effective but less accurate sniffers, and (2) the genetic correlation between CH 4 recorded with these 2 different on farm and high throughput techniques. Data were available from repeated measurements of CH 4 production (grams/day) by GF units and of CH 4 concentration (ppm) by sniffers, recorded on commercial dairy farms in the Netherlands. The final data comprised 24,284 GF daily means from…

Carrots (the main source of carotenoids) have multiple nutritional and health benefits. The objectives of this study were to evaluate the compositional, antioxidant, and antimicrobial properties of carrot powder and to examine its effect on the sensory characteristics, chemical properties, and microbial viability of probiotic soft cheese at a rate of 0.2, 0.4, and 0.6%. The carrot was turned into powder before being analyzed and incorporated as an ingredient in making probiotic soft cheese. Probiotic soft cheese was made from buffalo milk. The buffalo milk (∼6.9% fat, 4.4% protein, 9.2% milk solids not fat, and 0.7% ash) was pasteurized at 75 ± 1°C for 5 min and cooled to 40-42°C. The milk was then divided into 4 aliquots. Sodium chloride (local market, Assiut, Egypt) was added at a ratio of 5% followed by starter cultures. The carrot powder (4.5% moisture, 4.8% ash, 2.7% fat, 8.2% protein, 11.9% fibers, and 72.3% carbohydrate) was added at a rate of 0.2, 0.4, and 0.6%, followed by addition of 0.02 g/kg rennet. The cheese was cut again into cubes, pickled in jars filled with whey,…

The number of dairy farms adopting automatic milking systems (AMS) has considerably increased around the world aiming to reduce labor costs, improve cow welfare, increase overall performance, and generate a large amount of daily data, including production, behavior, health, and milk quality records. In this context, this study aimed to (1) estimate genomic-based variance components for milkability traits derived from AMS in North American Holstein cattle based on random regression models; and (2) derive and estimate genetic parameters for novel behavioral indicators based on AMS-derived data. A total of 1,752,713 daily records collected using 36 milking robot stations and 70,958 test-day records from 4,118 genotyped Holstein cows were used in this study. A total of 57,600 SNP remained after quality control. The daily-measured traits evaluated were milk yield (MY, kg), somatic cell score (SCS, score unit), milk electrical conductivity (EC, mS), milking efficiency (ME, kg/min), average milk flow rate (FR, kg/min), maximum milk flow rate (FRM, kg/min), milking time (MT, min), milking…

An edited data set of 700 bulk and 46,338 test-day records collected between 2019 and 2021 in 42 Holstein-dominated farms in the Veneto Region (North of Italy) was available for the present study. Information on protein, fat and lactose content, somatic cell count, and somatic cell score was available in bulk milk as well as individual test-day records, whereas urea concentration (mg/dL), differential somatic cell count (%), and milk yield (kg/d) were available for test-day records only. Milk features were merged with meteorological data retrieved from 8 weather stations located maximum 10 km from the farms. The daily and weekly temperature-humidity index (THI; wTHI) and maximum daily (MTHI) and weekly temperature-humidity index were associated with each record to evaluate the effect of heat stress conditions on milk-related traits through linear mixed models. Least squares means were estimated to evaluate the effect of THI and, separately, of MTHI on milk characteristics correcting for conventional systematic factors. Overall, heat stress conditions lowered the quality of both bulk…

Fat in the form of cracked rapeseed and 3-nitrooxypropanol (3-NOP, market as Bovaer) were fed alone or in combination to 4 Danish Holstein multicannulated dairy cows, with the objective to investigate effects on gas exchange, dry matter intake (DMI), nutrient digestion, and nutrient metabolism. The study design was a 4 × 4 Latin square with a 2 × 2 factorial treatment arrangement with 2 levels of fat supplementation; 33 g of crude fat per kg of dry matter (DM) or 64 g of crude fat per kg of DM for low and high fat diets, respectively, and 2 levels of 3-NOP; 0 mg/kg DM or 80 mg/kg DM. In total, 4 diets were formulated: low fat (LF), high fat (HF), 3-NOP and low fat (3LF), and 3-NOP and high fat (3HF). Cows were fed ad libitum and milked twice daily. The adaptation period lasted 11 d, followed by 5 d with 12 diurnal sampling times of digesta and ruminal fluid. Thereafter, gas exchange was measured for 5 d in respiration chambers. Chromic oxide and titanium dioxide were used as external flow markers to determine intestinal nutrient flow. No interactions between fat supplementation and…

In dairy farming, mastitis treatment is the most common reason for antimicrobial use. The overuse or misuse of antibiotics in agriculture has been associated with the development and spread of antimicrobial resistance (AMR). Traditionally, blanket dry cow therapy (BDCT), in which all cows receive antibiotic treatment, was used prophylactically to prevent and manage disease spread. In recent years, there has been a move toward selective dry cow therapy (SDCT), in which only clinically infected cows are treated with antibiotics. This study aimed to explore farmer attitudes toward antibiotic use (ABU), using the COM-B (Capability-Opportunity-Motivation-Behavior) model as a framework, to identify predictors of changing behavior toward SDCT and suggest interventions to encourage its uptake. Participant farmers (n = 240) were surveyed online between March and July 2021. Five items were found to be significant predictors of farmers having stopped BDCT: (1) having lower knowledge of AMR, (2) greater awareness of AMR and ABU (Capability), (3) feeling social pressure to reduce ABU…

The objective of this prospective observational study was to investigate associations of postpartum health with estrus detection (ED) by activity monitors and pregnancy outcomes in dairy cows. A total of 1,743 Holstein cows from 2 commercial dairy herds in Ontario, Canada were enrolled 3 wk before expected parturition and examined for health variables until 9 wk postpartum. Body condition score (BCS) and lameness were measured at 3 wk prepartum, and serum concentrations of total Ca, haptoglobin (Hp), and nonesterified fatty acids were measured at 2 and 6 ± 2 d in milk (DIM), and blood β-hydroxybutyrate (BHB) and metritis were assessed at 4, 8, 11, and 15 ± 2 DIM. Cows were examined for purulent vaginal discharge (PVD) and endometritis (ENDO) by endometrial cytology at wk 5, for lameness at wk 3 and 7, for BCS at wk 9 postpartum, and for time to onset of cyclicity by biweekly serum progesterone (P4) measurements. Additional disease data were obtained from farm records. Reproductive management for first AI was primarily based on ED by activity monitors until at least 75 DIM, and cows…

Twelve multiparous Holstein cows (42.2 ± 5.6 kg of milk/d; 83 ± 27 d in milk) were used in a split-plot design testing the effects of mineral and vitamin supplementation on the time course of animal performance, metabolism, and inflammation markers during heat stress. The main plot was the average concentrations of dietary vitamin E and Se (adequate: 11.1 IU/kg of vitamin E and 0.55 mg/kg of Se, and high: 223 IU/kg of vitamin E and 1.8 mg/kg of Se, respectively). Within each plot, cows were randomly assigned to (1) heat stress (HS) with adequate concentrations of vitamin D 3 and Ca (1,012 IU/kg and 0.73%, respectively), (2) HS with high concentrations of vitamin D 3 and Ca (HS+D 3 /Ca; 3,764 IU/kg and 0.97%, respectively), or (3) pair-feeding (PF) in thermoneutrality with adequate concentrations of vitamin D 3 and Ca (1,012 IU/kg and 0.73% Ca) in a Latin square design with 14-d periods and 7-d washouts. The highest rectal temperature was recorded at 1700 h for HS (39.4°C; mean of d 1 to 14), being 1.2 and 0.8°C greater than for PF and HS+D 3 /Ca, respectively. Respiratory rate and…

The use of assisted-reproduction technologies such as in vitro fertilization (IVF) is increasing, particularly in dairy cattle. The question of consequences in later life has not yet been directly addressed by studies on large animal populations. Studies on rodents and early data from humans and cattle suggest that in vitro manipulation of gametes and embryos could result in long-term alteration of metabolism, growth, and fertility. Our goal was to better describe these presumed consequences in the population of dairy cows produced by IVF in Québec (Canada) and to compare them to animals conceived by artificial insemination (AI) or multiple ovulation embryo transfer (MOET). To do so, we leveraged a large phenotypic database (2.5 million animals and 4.5 million lactations) from milk records in Québec aggregated by Lactanet (Sainte-Anne-de-Bellevue, QC, Canada) and spanning 2012 to 2019. We identified 304,163, 12,993, and 732 cows conceived by AI, MOET, and IVF, respectively, for a total of 317,888 Holstein animals from which we retrieved information for 576,448, 24,192, and 1,299…

The theme of iodine in the dairy sector is of particular interest due to the involvement and the interconnection of several stakeholders along the dairy food chain. Iodine plays a fundamental role in animal nutrition and physiology, and in cattle it is an essential micronutrient during lactation and for fetal development and the calf's growth. Its correct use in food supplementation is crucial to guarantee the animal's recommended daily requirement to avoid excess intake and long-term toxicity. Milk iodine is fundamental for public health, being one of the major sources of iodine in Mediterranean and Western diets. Public authorities and the scientific community have made great efforts to address how and to what extent different drivers may affect milk iodine concentration. The scientific literature concurs that the amount of iodine administered through animal feed and mineral supplements is the most important factor affecting its concentration in milk of most common dairy species. Additionally, farming practices related to milking (e.g., use of iodized teat sanitizers), herd…

Our objective was to describe associations of postpartum health with pregnancy and pregnancy loss (P-LOSS) from d 19 to 40 after first postpartum artificial insemination (AI) in lactating Holstein cows. In 2 commercial dairy herds in Ontario, Canada, 468 Holstein cows were enrolled 21 ± 3 d before expected parturition when body condition score (BCS) and lameness were assessed. Serum total Ca, haptoglobin (Hp), and nonesterified fatty acids (NEFA) were measured at 2 and 6 ± 2 d in milk (DIM). Blood β-hydroxybutyrate (BHB) measurement and metritis detection were done at 4, 8, 11, and 15 ± 2 DIM. Cows were examined for endometritis (ENDO; ≥11.5% polymorphonuclear cells in endometrial cytology) and purulent vaginal discharge (PVD) at 35 ± 3 DIM. Lameness was assessed again at 21 and 49 ± 3 DIM and BCS at 63 ± 3 DIM. First postpartum AI occurred primarily (86%) based on detection of estrus by activity monitors, on average (± standard deviation) at 65 ± 9 DIM, and the remaining cows received timed AI at 86 ± 18 DIM. Serum progesterone (P4) was measured on d 8 and 12 after AI, and…

The objective of this observational study was to compare calf health, average daily weight gain, and calf mortality considering the proposed categories of transfer of passive immunity (TPI) by the consensus report of Lombard et al. (2020). The consensus report defines 4 categories of passive immunity (excellent, good, fair, and poor) of calves obtained after colostrum ingestion. The association between the 4 TPI categories was analyzed on calf health (i.e., hazards for morbidity and mortality), and average daily weight gain (ADG) of female Holstein Friesian calves during the first 90 d of age. A further aim of this study was to examine the effects of calving-related factors, such as dystocia or winter season, on TPI status. We hypothesized that calves with excellent TPI have greater ADG, lower risks for infectious diseases such as neonatal diarrhea, pneumonia, and omphalitis, and lower mortality rates. This observational study was conducted from December 2017 to March 2021. Blood was collected from 3,434 female Holstein Friesian dairy calves from 1 commercial dairy farm. All female…

The aim of this trial was to determine the effect of a garlic and citrus extract supplement (GCE) on the performance, rumen fermentation, methane emissions, and rumen microbiome of dairy cows. Fourteen multiparous Nordic Red cows in mid-lactation from the research herd of Luke (Jokioinen, Finland) were allocated to 7 blocks in a complete randomized block design based on body weight, days in milk, dry matter intake (DMI), and milk yield. Animals within each block were randomly allocated to a diet with or without GCE. The experimental period for each block of cows (one for each of the control and GCE groups) consisted of 14 d of adaptation followed by 4 d of methane measurements inside the open circuit respiration chambers, with the first day being considered as acclimatization. Data were analyzed using the GLM procedure of SAS (SAS Institute Inc.). Methane production (g/d) and methane intensity (g/kg of energy-corrected milk) were lower by 10.3 and 11.7%, respectively, and methane yield (g/kg of DMI) tended to be lower by 9.7% in cows fed GCE compared with the control. Dry matter…

l-Glutamine, quercetin, slippery elm bark, marshmallow root, N-acetyl-d-glucosamine, licorice root, maitake mushrooms, and zinc orotate have been reported to help treat leaky gut. The purpose of this research was to explore the impact of these functional ingredients on the physico-chemical, microbiological, and sensory properties of yogurt. The milk from same source was equally divided into 9 pails and the 8 ingredients were randomly assigned to the 8 pails. The control had no ingredient. Milk was fermented to yogurt. The pH, titratable acidity, syneresis, viscosity, color (L*, a*, b*, C*, and h*), Streptococcus thermophilus counts, and Lactobacillus delbrueckii spp. bulgaricus counts of yogurts were determined on d 1, 7, 14, 21, 28, 35, and 42, whereas coliform counts, yeast and mold counts, and rheological characteristics were determined on d 1 and 42. The sensory study was performed on d 3 and particle size of the functional ingredients (powder form) was also determined. When compared with control, the incorporation of slippery elm bark into yogurts led to less syneresis.…

Fatty liver (i.e., hepatic lipidosis) is a prevalent metabolic disorder in dairy cows during the transition period, characterized by excess hepatic accumulation of triglyceride (TG), tissue dysfunction, and cell death. Detailed pathological changes, particularly hepatic fibrosis, during fatty liver remain to be determined. Liver fibrosis occurs as a consequence of liver damage, resulting from the excessive accumulation of extracellular matrix, which distorts the architecture of the normal liver, compromising its normal synthetic and metabolic functions. Thus, we aimed to investigate liver fibrosis status and its potential causal factors including oxidative stress, hepatocyte apoptosis, and production of inflammatory cytokines in the liver of cows with fatty liver. Forty-five dairy cows (parity, 3-5) were selected, and liver biopsy and blood were collected on the second week postpartum (days in milk, 10-14 d). On the basis of the degree of lipid accumulation in liver, selected cows were categorized into normal (n = 25; TG <1% wet wt), mild fatty liver (n = 15; 1% ≤ TG <5% wet wt),…

Longitudinal traits, such as milk production traits in dairy cattle, are featured by having phenotypic values at multiple time points, which change dynamically over time. In this study, we first imputed SNP chip (50-100K) data to whole-genome sequence (WGS) data in a Chinese Holstein population consisting of 6,470 cows. The imputation accuracies were 0.88 to 0.97 on average after quality control. We then performed longitudinal GWAS in this population based on a random regression test-day model using the imputed WGS data. The longitudinal GWAS revealed 16, 39, and 75 quantitative trait locus regions associated with milk yield, fat percentage, and protein percentage, respectively. We estimated the 95% confidence intervals (CI) for these quantitative trait locus regions using the logP drop method and identified 581 genes involved in these CI. Further, we focused on the CI that covered or overlapped with only 1 gene or the CI that contained an extremely significant top SNP. Twenty-eight candidate genes were identified in these CI. Most of them have been reported in the literature to be…

The aim of the study was to determine the effect of a Bacillus -based direct-fed microbial on performance of mid-lactating Holstein dairy cows and on their milk fatty acid composition. Six multiparous cows fitted with a rumen cannula were used in a randomized replicated crossover design. Cows received 200 g/d of either whey powder as a control or BioPlus 2B (Chr. Hansen), a commercial direct-fed microbial providing Bacillus subtilis and Bacillus licheniformis , representing a daily dose of 6.4 × 10 11 cfu, and using whey powder as a carrier. The 2 experimental periods lasted 14 d and were separated by a 7-d washout interval. Samples were collected on d 0, 13, and 14 of each period. Data from d 0 were used as covariate. Significance was declared at P ≤ 0.05 and tendency at 0.05 < P ≤ 0.10. There was a 10-fold increase in the relative concentration of bacteria from the Bacillus subtilis group in the rumen when feeding direct-fed Bacillus compared with control. Treatment did not affect ruminal pH, NH 3 -N, or concentrations of acetate, propionate, and butyrate. However, direct-fed…

The gastrointestinal microbial consortium in dairy cattle is critical to determining the energetic status of the dairy cow from birth through her final lactation. The ruminant's microbial community can degrade a wide variety of feedstuffs, which can affect growth, as well as production rate and efficiency on the farm, but can also affect food safety, animal health, and environmental impacts of dairy production. Gut microbial diversity and density are powerful tools that can be harnessed to benefit both producers and consumers. The incentives in the United States to develop Alternatives to Antibiotics for use in food-animal production have been largely driven by the Veterinary Feed Directive and have led to an increased use of probiotic approaches to alter the gastrointestinal microbial community composition, resulting in improved heifer growth, milk production and efficiency, and animal health. However, the efficacy of direct-fed microbials or probiotics in dairy cattle has been highly variable due to specific microbial ecological factors within the host gut and its native…

β-galactosidase (enzymatic class 3.2.1.23) is one of the dairy industry's most important and widely used enzymes. The enzyme is part of a large family known to catalyze hydrolysis and transglycosylation reactions. Its hydrolytic activity is commonly used to decrease lactose content in dairy products, while its transglycosylase activity has recently been used to synthesize galacto-oligosaccharides (GOS). During the past couple of years, researchers have focused on studying β-galactosidase isolated and purified from lactic acid bacteria. This review will focus on β-galactosidase purified and characterized from what used to be the Lactobacillus genera. Furthermore, particular emphasis is given to its kinetics, biochemical characteristics, GOS production, market, and utilization by Lactobacilllaceae species.

Studies on the storage stability of milk powder are currently fragmented and mainly affect only the area of above-zero temperatures. At the same time, there are no studies that consider the load factor when milk powder is stored in bags on a pallet. The purpose of this study was to identify the influence of various factors of industrial storage (temperature, height or layer number, and time) on the change in quality and technological properties of powdered dairy products. We placed skim milk powder (SMP) and whole milk powder (WMP) in 10 × 14 × 2 cm resealable plastic bags on a model stand simulating an industrial layout on pallets. The samples were stored for 18 mo at temperatures -30 ± 1°C, 6 ± 1°C, and 25 ± 3°C and 40 to 80% relative humidity. Samples from the control (0), 5, and 10 (lower) layers of pallets were selected for analysis on 0, 3, 6, 9, 12, 15, and 18 mo of storage for each of the temperatures. As a result, we did not detect any changes in the storage process for water activity and mass fraction of moisture. The particle size distribution of all the SMP and WMP…

This review focused on the historical, technological, and analytical characteristics of ricotta cheese available in the literature. Ricotta cheese is a typical dairy product that originated from Italy, used in the preparation of several traditional dishes, both sweet and salted. The available studies pertaining to ricotta cheese revealed a considerable biodiversity in the production with a large number of varieties produced, whose production varies according to the local uses and customs. The review shows the main chemical and microbial characteristics of the product and also the several parameters that affect the mechanism of the production process and the final characteristics of the product, including the raw materials, the processing methods, the season, the animals' diet, the animals' species, and breeds. Ricotta production can be artisanal or industrial, with differences in the making process. New trends in ricotta cheese production have been developed, with particular attention to the functional effect on human health and the novel technologies applied to extend the…