Agrégateur de flux

Impact of heat stress and a feed supplement on hormonal and inflammatory responses of dairy cows

Journal of Dairy Science -

The aim of this trial was to evaluate the effects of an immunomodulatory supplement (OmniGen AF, OG; Phibro Animal Health Corp.) and heat stress on hormonal, inflammatory, and immunological responses of lactating dairy cows. Sixty multiparous Holstein cows were randomly assigned to 4 treatments in a 2 × 2 factorial arrangement using 2 environments: cooled using fans and misters, or noncooled, and 2 top-dressed feed supplements (56 g/d): OG or a placebo (CTL). Temperature-humidity index averaged 78 during the 8-wk trial.

Quantitative comparative phosphoproteomic analysis of the effects of colostrum and milk feeding on liver tissue of neonatal calves

Journal of Dairy Science -

Posttranslational modifications, mostly phosphorylation, are critical for protein structure and function. However, the association between liver phosphoproteins in neonatal calves and colostrum intake is not well understood. In this study, we examined the liver phosphoproteome profile in neonatal calves after receiving colostrum or milk. Liver tissue samples were collected from control calves (CON, n = 3) 2 h after birth and from calves that received colostrum (CG, n = 3) or milk (MG, n = 3) 24 h after birth.

Using compositional mixed-effects models to evaluate responses to amino acid supplementation in milk replacers for calves

Journal of Dairy Science -

The consequences of supplementing Lys, Met, and Thr in milk replacers (MR) for calves have been widely studied, but scarce information exists about potential roles of other AA (whether essential or not). The effects on growth performance of supplementation of 4 different AA combinations in a mixed ration (25.4% crude protein and 20.3% fat) based on skim milk powder and whey protein concentrate were evaluated in 76 Holstein male calves (3 ± 1.7 d old). The 4 MR were as follows: CTRL with no AA supplementation; PG, supplying additional 0.3% Pro and 0.1% Gly; FY, supplying additional 0.2% Phe and 0.2% Tyr; and KMT, providing additional 0.62% Lys, 0.22% Met, and 0.61% Thr.

Forward osmosis concentration of milk: Product quality and processing considerations

Journal of Dairy Science -

Concentration of milk in the dairy industry is typically achieved by thermal evaporation or reverse osmosis (RO). Heat concentration is energy intensive and leads to cooked flavor and color changes in the final product, and RO is affected by fouling, which limits the final achievable concentration of the product. The main objective of this work was to evaluate forward osmosis (FO) as an alternative method for concentrating milk. The effects of fat content and temperature on the process were evaluated, and the physicochemical properties and sensory qualities of the final product were assessed.

Effects of supplemental calcium gluconate embedded in a hydrogenated fat matrix on lactation, digestive, and metabolic variables in dairy cattle

Journal of Dairy Science -

There is growing evidence suggesting that by improving gut integrity and function, less energy is partitioned toward immune responses related to xenobiotic infiltration, sparing energy for productive purposes. Gluconic acid and its salts have previously shown prebiotic effects in the lower gut of nonruminant animals, where they serve as a precursor for butyrate, although evidence in ruminants is limited. Butyrate and its fermentative precursors have demonstrated multiple beneficial effects to gastrointestinal ecology, morphology, and function, such as the stimulation of epithelial cell proliferation and improvement of gut barrier function and ecology.

Feeding dairy cows bakery by-products enhanced nutrient digestibility, but affected fecal microbial composition and pH in a dose-dependent manner

Journal of Dairy Science -

We reported recently that adding bakery by-products (BP) to the diets of dairy cows up to 30% improved performance and rumen pH, but caused major shifts in the nutrient profile and availability, likely modifying nutrient degradation patterns throughout the gastrointestinal tract. The aim of this study was to investigate the effects of the gradual replacement of cereals by BP on the apparent total-tract digestibility (ATTD), the fermentation patterns, and the microbial community in feces of dairy cows.

Potassium carbonate as a supplement to improve milk fat concentration and yield in early-lactating dairy goats fed a high-starch, low-fiber diet

Journal of Dairy Science -

This study investigated the use of K2CO3 as dietary buffer to prevent or to recover from low milk fat production when early-lactating dairy goats are fed a high-starch, low-fiber (HSLF) diet. At kidding, 30 Alpine goats housed in pens with Calan gate feeders received a total mixed ration with a forage-to-concentrate ratio of 55:45 on a dry matter (DM) basis for a baseline period of 27 ± 4 d. Goats (milk yield, 4.14 ± 0.88 kg/d; milk fat, 4.28 ± 0.52%; mean ± SD) were then assigned to 1 of 10 blocks according to parity (first vs.

Energy, nitrogen partitioning, and methane emissions in dairy goats differ when an isoenergetic and isoproteic diet contained orange leaves and rice straw crop residues

Journal of Dairy Science -

The aim of this study was to evaluate the effects of incorporating rice straw and orange leaves into the diets for goats. Ten Murciano-Granadina goats at mid lactation weighing 45 ± 0.3 kg were used in a crossover design. Two isoproteic and isoenergetic diets (180 g/kg DM and 17 MJ/kg DM, respectively) with alfalfa hay as forage source (33% of DM) were fed. A control diet (CON) incorporated barley as energy source and soy hulls as fiber component. The experimental diet (ORG) replaced barley and soy hulls with orange leaves (19% on DM basis), rice straw (12%, on DM basis) and soya oil (2%).

Effects of feeding milk replacer at a moderate rate, ad libitum, or with a step-up program on Holstein calf performance to 4 months of age

Journal of Dairy Science -

The objective of this study was to evaluate 3 milk replacer (MR) feeding programs on calf performance to 4 mo of age. Male Holstein calves (n = 48; 2–3 d old) were randomly assigned to either a moderate rate of MR (MOD; 0.66 kg/d for 39 d, then 0.33 kg/d for 3 d), an ad libitum rate of MR (ADLIB; offered twice daily between 0630 and 0830 h and between 1430 and 1630 h for 35 d, 0.66 kg/d for 4 d, and 0.33 kg/d for 3 d), or a step-up rate of MR (STEPUP; increased from 0.32 to 0.62 kg/d in first 12 d, 0.66 kg/d for 27 d, and 0.33 kg/d for 3 d).

Albumin-to-globulin ratio before dry-off as a possible index of inflammatory status and performance in the subsequent lactation in dairy cows

Journal of Dairy Science -

The dry-off of dairy cows represents an important phase of the lactation cycle, influencing the outcome of the next lactation. Among the physiological changes, the severity of the inflammatory response can vary after the dry-off, and this response might have consequences on cow adaptation in the transition period. The plasma protein profile is a diagnostic tool widely used in humans and animals to assess the inflammatory status and predict the outcome of severe diseases. The albumin-to-globulin ratio (AG) can represent a simple and useful proxy for the inflammatory condition.

Relationship of anogenital distance with fertility in nulliparous Holstein heifers

Journal of Dairy Science -

Anogenital distance (AGD), defined as the distance from the center of the anus to the base of the clitoris, in lactating dairy cows of first and second parity, has been reported to be inversely related to fertility and moderately heritable. Thus, AGD may be a useful reproductive phenotype for future genetic selection to improve fertility. The objectives of this study were to (1) characterize AGD in nulliparous dairy heifers; and (2) determine if the inverse relationship between AGD and fertility, found in lactating dairy cows, is also evident in nulliparous heifers.

Effects of extended voluntary waiting period from calving until first insemination on body condition, milk yield, and lactation persistency

Journal of Dairy Science -

A 1-yr calving interval (CInt) is usually associated with maximized milk output, due to the calving-related peak in milk yield. Extending CInt could benefit cow health and production efficiency due to fewer transition periods per unit of time. Extending CInt can affect lactation performance by fewer days dry per year, delayed pregnancy effect on milk yield, and greater milk solid yield in late lactation. This study first investigated the effects of 3 different voluntary waiting periods (VWP) from calving until first insemination on body weight, body condition, milk yield, and lactation persistency.

Short-term liveweight changes of dairy cows measured by stationary and walk-over weighing scales

Journal of Dairy Science -

Monitoring and detecting individual cows' liveweight (LW) and liveweight change (LWC) are important for estimation of nutritional requirements and health management, and could be useful to measure short-term feed intake, water consumption, defecation, and urination. Walk-over weighing (WOW) systems can facilitate measurements of LW for these purposes, providing automated LW recorded at different times of the day. We conducted a field study to (1) quantify the contribution of feed and water intake, as well as urine and feces excretions, to short-term LWC and (2) determine the feasibility of stationary and WOW scales to detect subtle changes in LW as a result of feed and water intake, urination, and defecation.

Evaluating the performance of machine learning methods and variable selection methods for predicting difficult-to-measure traits in Holstein dairy cattle using milk infrared spectral data

Journal of Dairy Science -

Fourier-transform infrared (FTIR) spectroscopy is a powerful high-throughput phenotyping tool for predicting traits that are expensive and difficult to measure in dairy cattle. Calibration equations are often developed using standard methods, such as partial least squares (PLS) regression. Methods that employ penalization, rank-reduction, and variable selection, as well as being able to model the nonlinear relations between phenotype and FTIR, might offer improvements in predictive ability and model robustness.

Survey design and implementation quantifying winter housing and bedding types used on Vermont organic dairy farms

Journal of Dairy Science -

We conducted a descriptive observational study to quantify the frequency and diversity of winter housing and bedding types used by organic dairy farmers in Vermont. This report describes the survey methods, results, successes, limitations, and lessons learned from administering the survey. Beginning in December 2018, a short questionnaire was administered by web, mail, and telephone to a source population defined as all producers of organic dairy cow milk in Vermont (n = 177) listed in the United States Department of Agriculture Organic Integrity database.

Invited review: A 2020 perspective on pasture-based dairy systems and products

Journal of Dairy Science -

Grazing pasture is the basis for dairy production systems in regions with temperate climates, such as in Ireland, New Zealand, parts of Australia, the United States, and Europe. Milk and dairy products from cows on pasture-based farms predominantly consuming fresh grazed grass (typically classified as “grass-fed” milk) have been previously shown to possess a different nutrient profile, with potential nutritional benefits, compared with conventional milk derived from total mixed ration. Moreover, pasture-based production systems are considered more environmentally and animal welfare friendly by consumers.

Plasma metabolome alteration in dairy cows with left displaced abomasum before and after surgical correction

Journal of Dairy Science -

Left displaced abomasum (LDA) leads to substantial changes in the metabolism of dairy cows. Surgical correction of LDA can rapidly improve the health of cows; however, changes in metabolism following surgery are rarely described. To investigate the changes of plasma metabolome in cows with LDA before and after surgical correction, blood samples were collected from 10 healthy postpartum cows and 10 cows with LDA on the day of diagnosis, then again from the LDA cows 14 d after surgery. Serum nonesterified fatty acid, β-hydroxybutyric acid, cortisol and histamine concentration, and antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activities were evaluated, and the metabolic profile in plasma was analyzed using ultra-high-performance liquid chromatography time-of-flight mass spectrometry.

Effects of the circadian rhythm on milk composition in dairy cows: Does day-milk differ from night-milk?

Journal of Dairy Science -

Metabolism in most organisms can show variations between the day and night. These variations may also affect the composition of products derived from livestock. The aim of the present study was to investigate the difference in composition between the day-milk and night-milk of dairy cows. Ten multiparous Holstein cows (milk yield = 25.2 ± 5.00 kg/d) were randomly selected during mid lactation. Milk samples were collected at 0500 h (“night-milk”) and 1500 h (“day-milk”) and analyzed to determine their composition.

The hidden cost of disease: II. Impact of the first incidence of lameness on production and economic indicators of primiparous dairy cows

Journal of Dairy Science -

Lameness is a persistent and underreported health and welfare problem in the dairy industry, resulting in reduced cow performance and profitability as well as early culling. The study objectives were (1) to quantify the impact of the first instance of lameness, at different stages of lactation, on production and economic performance, and (2) to further quantify the impacts of the first instance of lameness when only cows that remain in the herd for at least 100 d in milk (DIM) and those that remain for 305 DIM are included in the analysis.

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