Agrégateur de flux

Interpretive Summaries, September 2018

Journal of Dairy Science -

Effect of αS1-casein genotype on phenolic compounds and antioxidant activity in goat milk yogurt fortified with Rhus coriaria leaf powder. By Perna et al., page 7691. Goat milk yogurt is a healthy alternative to cow milk yogurt, containing more vitamin A and B; in particular, vitamin B3 content in goat milk is nearly double that of cow milk. The αS1-casein genotype affects the antioxidant peptides that develop during fermentation of the milk by lactic acid bacteria. Fortification with Rhus coriaria leaves improves the nutritional and nutraceutical value of goat yogurt.

Corrigendum to “Evaluation by employees of employee management on large US dairy farms” (J. Dairy Sci. 101:7450–7462)

Journal of Dairy Science -

An error was made in the first paragraph of Materials and Methods on page 7451 (error in italics; correction in bold). The sentence “Each farm owner signed a contract to participate in the project and was paid a project fee based on the number of employees on the farm” should read “Each farm owner signed a contract to participate in the project and paid a project fee based on the number of employees on the farm.”

Corrigendum to “Quality characteristics, chemical composition, and sensory properties of butter from cows on pasture versus indoor feeding systems” (J. Dairy Sci. 99:9441–9460)

Journal of Dairy Science -

We would like to bring to the attention of readers errors reported in the above article. In particular, 2 sets of peaks that were eluting close together were reported in reverse order because of an issue with the GC standard preparation. The fatty acids α-linolenic acid (C18:3n-3; ALA) and eicosenoic acid (C20:1 cis-11) were labelled in reverse order, as were behenic acid (C22:0) and eicosatrienoic acid (C20:3n-6). γ-Linoleic acid (C18:3n-6 cis) has been removed. Although values for these fatty acids and the calculations that include them are affected, the overall trend for these have not changed, and each is still significantly higher than or correlated with the same feeding systems with the exception of behenic acid.

Corrigendum to “Effect of pasture versus indoor feeding systems on raw milk composition and quality over an entire lactation” (J. Dairy Sci. 99:9424–9440)

Journal of Dairy Science -

We would like to bring to the attention of readers errors reported in the above article. In particular, 2 sets of peaks that were eluting close together were reported in reverse order because of an issue with the GC standard preparation. The fatty acids α-linolenic acid (C18:3n-3; ALA) and eicosenoic acid (C20:1 cis-11) were labelled in reverse order, as were behenic acid (C22:0) and eicosatrienoic acid (C20:3n-6). γ-Linoleic acid (C18:3n-6 cis) has been removed. Although values for these fatty acids and the calculations that include them are affected, the overall trend for these have not changed, and each is still significantly higher than or correlated with the same feeding systems with the exception of behenic acid.

Extraction of phospholipids from a dairy by-product (whey protein phospholipid concentrate) using ethanol

Journal of Dairy Science -

There has been a great interest in the phospholipids (PL) found in dairy products because of their health and functional properties. In this study, a technology that was originally developed for egg yolk PL extraction was applied to whey protein phospholipid concentrate (WPPC). This method successfully precipitated the proteins present in WPPC and extracted the lipids with a renewable alcoholic solvent, ethanol. The effect of ethanol concentration, extraction temperature, and extraction number on the recovery of total lipid, total PL, and individual PL class was evaluated.

Pathogen-specific production losses in bovine mastitis

Journal of Dairy Science -

Reduction in long-term milk yields represents a notable share of the economic losses caused by bovine mastitis. Efficient, economic, and safe measures to prevent these losses require knowledge of the causal agent of the disease. The aim of this study was to investigate pathogen-specific impacts of mastitis on milk production of dairy cows. The materials consisted of milk and health recording data and microbiological diagnoses of mastitic quarter milk samples of 20,234 Finnish dairy cows during 2010, 2011, and 2012.

The degree of visual cover and location of birth fluids affect dairy cows' choice of calving site

Journal of Dairy Science -

Under natural conditions, cows seek isolation and visual cover when calving becomes imminent, but the degree of visual cover necessary to provide an attractive calving site is not known. When calving indoors, preparturient cows are attracted to other cows' birth fluids, and this may influence their isolation seeking. Therefore, we aimed to investigate the effect of degree of visual cover of secluded areas and the location of birth fluids on dairy cows' calving site selection. One hundred twenty-four Danish Holstein cows were moved in groups of 8 to 12 to a group pen with access to 6 areas secluded by a barrier of either 3 m (wide barrier) or 1.5 m (narrow barrier).

Preweaned heifer management on US dairy operations: Part IV. Factors associated with the presence of Escherichia coli O157 in preweaned dairy heifers

Journal of Dairy Science -

Dairy calves shed pathogenic Escherichia coli O157 (O157) in feces and are a potential route of exposure for human infections. As part of the National Animal Health Monitoring System's (NAHMS) Dairy 2014 study, we evaluated farm, animal, and environmental factors associated with O157 presence in dairy heifer calves. For this O157 study, calves were enrolled from 100 dairy operations in 13 states. Each operation collected data from calves from birth to weaning over an 18-mo period. A single fecal sample was collected from 487 calves in western states and from 871 calves in eastern states (n = 1,358 total), and O157 was detected in 2.5% (n = 34) of fecal samples.

Effects of intraruminal urea-nitrogen infusions on feed intake, nitrogen utilization, and milk yield in dairy cows

Journal of Dairy Science -

The objective of this study was to determine the effects of supplementation of protein deficient diet with increasing amounts of urea-N on feed intake, milk yield, rumen fermentation, and nutrient digestibility in dairy cows. The hypothesis was that low rumen ammonia-N concentrations provide suboptimal conditions for rumen microbes and these conditions can be alleviated by urea-N that increases rumen ammonia-N concentrations. To evaluate this hypothesis, the diet was formulated slightly deficient with respect to rumen-degradable protein.

Stepping behavior and muscle activity of dairy cattle standing on concrete or rubber flooring for 1 or 3 hours

Journal of Dairy Science -

The type of flooring in dairy cattle systems influences cows' health and welfare. Although concrete is common, the use of more compressible flooring, such as rubber, is increasing. Cows prefer to stand and walk on rubber surfaces than on concrete; however, it is largely unknown how walking and standing for longer periods of time influence muscle activity and fatigue. Therefore, we used measures of behavior and muscle activity to investigate the potential benefits of providing a rubber flooring surface to dairy cattle.

Inhibitory properties of camel whey protein hydrolysates toward liver cancer cells, dipeptidyl peptidase-IV, and inflammation

Journal of Dairy Science -

This report describes an investigation of camel whey protein hydrolysates (CWPH) produced by gastric and pancreatic enzymes for their in vitro antidiabetic, anticancer, and anti-inflammatory properties. Degree of hydrolysis (DH) ranged from 8.54 to 47.53%, with hydrolysates generated using chymotrypsin for 6 h displaying the highest DH. Reverse phase-HPLC analysis showed that α-lactalbumin underwent complete degradation, with no intact α-lactalbumin detected in CWPH. The CWPH displayed enhanced antidiabetic activity compared with intact whey proteins; with pepsin- and chymotrypsin-generated CWPH displaying greater inhibition of dipeptidyl peptidase IV (DPP-IV), α-glucosidase, and α-amylase compared with trypsin-generated CWPH.

Grazing of dairy cows on pasture versus indoor feeding on total mixed ration: Effects on low-moisture part-skim Mozzarella cheese yield and quality characteristics in mid and late lactation

Journal of Dairy Science -

This study investigated the effects of 3 dairy cow feeding systems on the composition, yield, and biochemical and physical properties of low-moisture part-skim Mozzarella cheese in mid (ML; May–June) and late (LL; October–November) lactation. Sixty spring-calving cows were assigned to 3 herds, each consisting of 20 cows, and balanced on parity, calving date, and pre-experimental milk yield and milk solids yield. Each herd was allocated to 1 of the following feeding systems: grazing on perennial ryegrass (Lolium perenne L.) pasture (GRO), grazing on perennial ryegrass and white clover (Trifolium repens L.) pasture (GRC), or housed indoors and offered total mixed ration (TMR).

Variations in milk protein fractions affect the efficiency of the cheese-making process

Journal of Dairy Science -

The aim of this study was to assess the influence of the amounts of the αS1-, αS2-, β-, and κ-casein (CN) and the α-lactalbumin and β-lactoglobulin protein fractions on the efficiency of the cheese-making process independently of their genetic polymorphisms. The study was carried out on milk samples from 1,271 Brown Swiss cows from 85 herds classified into 4 categories according to management, feeding, and housing characteristics (traditional and modern systems). To assess the efficiency of the cheese-making process, we processed the milk samples according to a laboratory cheese-making procedure (1,500 mL/sample) and obtained the following measures: (1) 3 percentage cheese yields (%CYcurd, %CYsolids, %CYwater), (2) 2 daily cheese yields obtained by multiplying %CY (curd and total solids) by daily milk yields (dCYcurd, dCYsolids), (3) 4 measures of nutrient recovery in the curd (RECfat, RECprotein, RECsolids, RECenergy), and (4) 2 measures of cheese-making efficiency in terms of the ratio between the observed and theoretical %CY (Ef-%CYcurd, Ef-%CYsolids).

Training method for animal-based measures in dairy cattle welfare assessments

Journal of Dairy Science -

Quantitative assessments of animal welfare are increasingly being used in the dairy industry. It is important to have good precision and accuracy within and among assessors. This study explored the effectiveness of a 3-d training workshop for animal-based measures (ABM) of welfare in dairy cows, in which 14 people were trained to evaluate 6 ABM, specifically hock injuries (HI), lameness (LM), body condition score (BCS), and udder, flank, and leg cleanliness (collectively CLN). All scoring systems were modified to a dichotomous outcome, acceptable or unacceptable.

Association between metabolic diseases and the culling risk of high-yielding dairy cows in a transition management facility using survival and decision tree analysis

Journal of Dairy Science -

The objective of this study was to assess the association between individual metabolic diseases (MD) and multiple MD (MD+) in the transition period (±3 wk relative to calving) and the culling risk in the first 120 d in milk (DIM) in Holstein-Friesian dairy cows. Health records from a transition management facility in Germany with 1,946 calvings were analyzed in a 1-yr cohort via survival analysis and a decision tree model. The recorded MD were milk fever (MF), retained placenta (RP), metritis (METR), ketosis (KET), displaced abomasum (DA), twinning (TWIN), and clinical mastitis (MAST).

Changes in the volatile profile of skim milk powder prepared under different processing conditions and the effect on the volatile flavor profile of model white chocolate

Journal of Dairy Science -

The objective of this work is to determine the extent to which changes in the skim milk powder (SMP) manufacturing process alter the volatile profile of SMP, and whether these changes are carried through to a final product when the SMP is used as an ingredient and subjected to further processing. The manufacture of SMP is a multistage process involving a preliminary concentration step, heat treatment, and a drying stage. However, the methods and conditions used by the industry are not standardized, and the inherent variability in the production of SMP has consequences for the end-users, such as the confectionery industry, where the SMP is used as an ingredient during the production of milk chocolate, white chocolate, and caramel.

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