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Interpretive Summaries, July 2018

Journal of Dairy Science -

ADSA Foundation Scholar Award: A role for serotonin in lactation physiology—Where do we go from here? By Hernandez, page 5671. This review covers the importance of serotonin in regulating mammary gland function and maternal metabolism during lactation. It highlights the diversity of functions and roles serotonin can play in physiology as well as novel routes by which serotonin may regulate mammary gland homeostasis. Serotonin's regulation of mammary gland physiology can be of great importance to lactating dairy cows, particularly during the early periparturient period during which cows are most susceptible to health and metabolic issues.

Trois nouveaux index de Gènes Diffusion

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Gènes Diffusion propose trois nouveaux index « maisons » après l'évaluation « Santé du pied » en 2014. Deux index sont dédiés à la santé : Mortellaro (MTL) pour réduire l'impact financier des boiteries et Acétonémie (Acet). L'index Mortellaro était déjà présent dans la synthèse Santé du Pied. ...

Short-term responses in production and behavior during periods of change in concentrate allowance for dairy cows

Journal of Dairy Science -

The aim of this study was to investigate the short-term responses of dairy cows during periods of change in the concentrate allowance in an automatic milking system. The experiment had a design with a 2 × 2 factorial arrangement including 2 types of concentrates and 2 amounts of concentrates (type O: mix of pelleted concentrate and steamrolled, acidified barley; type S: pelleted) in amounts of 3 and 6 kg/d. The experiment length was 11 wk. The concentrate type changed between wk 6 and 7 and included both increase and decrease in concentrate allowance for each concentrate type.

Effects of overstocking at the feedbunk on the growth performance and sorting characteristics of a forage-based diet offered for ad libitum intake to replacement Holstein dairy heifers

Journal of Dairy Science -

Various forms of overcrowding are common in heifer-rearing operations. Our objectives for this study were to evaluate the effects of overstocking at the feedbunk (100, 133, 160, or 200% of capacity) on the growth performance, feedbunk sorting behaviors, and hygiene of 128 gravid Holstein heifers (475 ± 55.3 kg) consuming an alfalfa haylage and corn silage diet diluted with processed wheat straw at an inclusion rate of 25.2% (DM basis). In this study, heifers were overstocked only at the feedbunk, and not with respect to available freestalls or pen area.

Maternal supply of methionine during late pregnancy is associated with changes in immune function and abundance of microRNA and mRNA in Holstein calf polymorphonuclear leukocytes

Journal of Dairy Science -

Pregnancy and early life are critical periods during which environmental factors such as nutrition can affect development. Rumen-protected methionine (Met; RPM) supplementation during the prepartum period improves not only performance but immune responses in dairy cows. We investigated the effects of enhanced maternal supply of Met via feeding RPM on whole-blood in vitro lipopolysaccharide (LPS; 0, 0.01, or 5 μg/mL of blood) challenge and targeted microRNA and mRNA abundance in calf blood polymorphonuclear leukocytes (PMNL).

Hepatic phosphorylation status of serine/threonine kinase 1, mammalian target of rapamycin signaling proteins, and growth rate in Holstein heifer calves in response to maternal supply of methionine

Journal of Dairy Science -

The study investigated whether methionine supply during late pregnancy is associated with liver mammalian target of rapamycin (MTOR) pathway phosphorylation, plasma biomarkers, and growth in heifer calves born to cows fed a control diet (CON) or the control diet plus ethylcellulose rumen-protected methionine (MET; 0.09% of dry matter intake) for the last 28 d prepartum. Calves were fed and managed similarly during the first 56 d of age. Plasma was harvested at birth and 2, 7, 21, 42, and 50 d of age and was used for biomarker profiling.

Short communication: Lack of intramammary niche recolonization during a sanitation program for the contagious mastitis pathogen Staphylococcus aureus genotype B

Journal of Dairy Science -

In Switzerland, sanitation programs of dairy herds infected with the contagious mastitis pathogen Staphylococcus aureus genotype B (GTB) have been established for several years. In recent years, Streptococcus uberis and non-aureus staphylococci have emerged as the bacteria most frequently isolated from bovine milk samples. The latter cause subclinical mastitis, and some species are more persistent or pathogenic than others. The present study aimed to investigate the developments in the intramammary colonization spectrum of 5 dairy herds undergoing a sanitation program for Staph.

Randomized clinical trial of the effect of a fixed or increasing milk allowance in the first 2 weeks of life on health and performance of dairy calves

Journal of Dairy Science -

The objective of this study was to describe the effect of offering a fixed or increasing milk allowance in the first 1 to 2 wk of life. We hypothesized that calves offered a fixed amount of milk early in life would not experience more scours, but rather would experience improved health and growth compared with calves that had their daily milk allowance slowly increased over a period of 1 to 2 wk. This randomized controlled clinical trial was conducted on 5 dairy farms in Minnesota with both a summer (June–August 2016) and winter (December–February 2017) period of enrollment.

Factors associated with productivity on automatic milking system dairy farms in the Upper Midwest United States

Journal of Dairy Science -

The objective of this study was to identify housing and management factors associated with productivity on automatic milking system (AMS) dairy farms measured as daily milk yield/AMS and daily milk yield/cow. Management, housing, and lameness prevalence data were collected from 33 AMS farms in Minnesota and Wisconsin during a farm visit. All farms in the study used free-flow cow traffic. Mixed model analysis of cross-sectional data showed that farms with automatic feed push-up via a robot produced more milk per AMS/day and per cow/day than farms where feed was pushed up manually.

Field trial to evaluate the effect of an intranasal respiratory vaccine protocol on calf health, ultrasonographic lung consolidation, and growth in Holstein dairy calves

Journal of Dairy Science -

The objective of this field trial was to evaluate the effect of a vaccine protocol using a commercially available trivalent vaccine designed for intranasal use. Experimental challenge studies have demonstrated varying efficacies of vaccines administered via the intranasal route. A total of 468 calves from 3 herds were enrolled and randomized into 3 treatment groups (positive control, PC, n = 211; intranasal vaccine, IN, n = 215; negative control, NC, n = 42) and followed for 8 to 12 wk. The PC consisted of one dose of commercially available multivalent injectable vaccine against bovine respiratory syncytial virus, infectious bovine rhinotracheitis, parainfluenza 3, and bovine viral diarrhea administered subcutaneously at 6 wk of age.

Rapid detection and characterization of postpasteurization contaminants in pasteurized fluid milk

Journal of Dairy Science -

Microbial spoilage of pasteurized fluid milk is typically due to either (1) postpasteurization contamination (PPC) with psychrotolerant gram-negative bacteria (predominantly Pseudomonas) or (2) growth of psychrotolerant sporeformers (e.g., Paenibacillus) that have the ability to survive pasteurization when present as spores in raw milk, and to subsequently grow at refrigeration temperatures. While fluid milk quality has improved over the last several decades, continued reduction of PPC is hampered by the lack of rapid, sensitive, and specific methods that allow for detection of PPC in fluid milk, with fluid milk processors still often using time-consuming methods (e.g., Moseley keeping quality test).

Measurement of dairy calf behavior prior to onset of clinical disease and in response to disbudding using automated calf feeders and accelerometers

Journal of Dairy Science -

We determined if feeding and lying behavior, recorded by automatic calf feeding systems (ACFS) and accelerometers, could be used to detect changes in behavior before onset of neonatal calf diarrhea (NCD) or in response to disbudding pain in dairy calves. At 4 d of age, 112 calves had accelerometers attached to their hind leg and were housed in pens with ACFS. Calves were examined daily for signs of illness or injury. Of the 112 calves monitored, 18 were diagnosed with NCD; activities of calves with NCD were then compared with those of 18 healthy controls (calves that had no symptoms of NCD, other illnesses, or injury).

Methionine supply alters mammary gland antioxidant gene networks via phosphorylation of nuclear factor erythroid 2-like 2 (NFE2L2) protein in dairy cows during the periparturient period

Journal of Dairy Science -

The periparturient period is the most critical period during the lactation cycle of dairy cows and is characterized by increased oxidative stress status. The objective of this experiment was to evaluate the effect of supplementing rumen-protected methionine on nuclear factor erythroid 2-like 2 (NFE2L2, formerly NRF2) protein and target gene expression in the mammary gland during the early postpartal period. Multiparous Holstein cows were used in a block design experiment with 30 cows per treatment.

Short communication: Effect of adding a second prostaglandin F2α injection during the Ovsynch protocol on luteal regression and fertility in lactating dairy cows: A meta-analysis

Journal of Dairy Science -

Incomplete luteal regression after treatment with a single dose of prostaglandin F2α during an Ovsynch protocol decreases fertility to timed artificial insemination (TAI). To increase the proportion of cows with complete luteal regression and subsequently pregnancy per artificial insemination (P/AI), an additional treatment with PGF2α 24 h after the first has been recommended. A systematic review of the literature and meta-analytical assessment were performed with the objective of evaluating the effects of adding a second PGF2α treatment during the Ovsynch protocol on luteal regression and reproductive performance in lactating dairy cows.

Effects of an automatic milking system on milk yield and quality of Mediterranean buffaloes

Journal of Dairy Science -

A study was carried out to evaluate the effects of an automatic milking system (AMS) on milk yield and composition of buffalo (Mediterranean-type Bubalus bubalis) cows. Performed from January 2015 to December 2015 in an organic buffalo dairy farm equipped with both a traditional tandem milking parlor and an AMS, the study involved 90 primiparous buffaloes randomly allotted to a tandem or AMS group from 5 to 10 d of lactation onward. Number of milkings per day and daily milk yield of each cow were recorded, and individual milk sampling was carried out twice a month.

Preweaned heifer management on US dairy operations: Part I. Descriptive characteristics of preweaned heifer raising practices

Journal of Dairy Science -

The objective of this study was to describe preweaned dairy heifer calf management practices on dairy operations across the United States that were used to analyze factors associated with colostrum quality and passive transfer, Cryptosporidium and Giardia, morbidity and mortality, and average daily gain. This study included 104 dairy operations in 13 states that participated in the National Animal Health Monitoring System's Dairy 2014 calf component study. This 18-mo longitudinal study focused on dairy heifer calves from birth to weaning, and data were collected on 2,545 heifer calves.

Preweaned heifer management on US dairy operations: Part II. Factors associated with colostrum quality and passive transfer status of dairy heifer calves

Journal of Dairy Science -

Passive transfer of immunity is essential for the short- and long-term health of dairy calves. The objective of this study was to evaluate factors associated with colostrum quality and passive transfer status of US heifer calves. This study included 104 operations in 13 states that participated in the calf component of the National Animal Health Monitoring System's Dairy 2014 study. This 18-mo longitudinal study included 1,972 Holstein heifer calves from birth to weaning. Multivariable mixed linear regression models were selected using backward elimination model selection after univariate screening to determine which factors were associated with colostrum IgG and serum IgG concentrations.

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