INTERPRETIVE SUMMARIES, JULY 2017 Effect of denatured whey protein concentrate and its fractions on cheese composition and rheological properties. By Perreault et al., page 5139. We evaluated the effect of a denatured whey protein concentrate (DWPC) and its fractions on cheese yield and composition, resulting in knowledge to support the development of high-performance ingredients that increase whey proteins recovery in cheese. Using DWPC increases the moisture and alters the mechanical properties of cheese. We induced a moisture gradient in cheese using centrifugation to isolate the direct effect of the DWPC. When the effect on moisture is removed, the contribution of DWPC proteins to cheese rheological properties is similar to the contribution of caseins. https://doi.org/10.3168/jds.2016-12473. Molecular characterization and antibiotic resistance of Staphylococcus spp. isolated from cheese processing plants. By Rodrigues et al., page 5167. The high prevalence of staphylococci in cheese processing remains a food safety problem in Brazil. Herein, we investigated the potential virulence and antibiotic resistance of Staphylococcus isolates from 3 traditional cheese processing plants and assessed staphylococcal cassette chromosome mec (SCCmec) and spa types. Strains harboring genes encoding enterotoxin, hemolysin, Panton-Valentine leukocidin, and toxic shock syndrome toxin were identified. Methicillin-resistant Staphylococcus aureus from different origins (raw milk, food handler, cheese, and packer machine) were identified, and their virulence and resistance profiles showed that their presence in food processing should be monitored. Moreover, a new spa type (t14969) was isolated from cheese. https://doi.org/10.3168/jds.2016-12477. Comparison of 4 label-based immunochromatographic assays for the detection of Escherichia coli O157:H7 in milk. By Luo et al., page 5176. This work systematically compared the performance of gold nanoparticle immunochromatographic assay (GNP-ICA), quantum-dot immunochromatographic assay (QD-ICA), fluorescent nanoparticle immunochromatographic assay (FNP-ICA), and Eu (III) nanoparticle immunochromatographic assay (EuNP-ICA) in quantitative detection of Escherichia coli O157:H7 in milk. The results revealed that EuNP-ICA showed the highest sensitivity, whereas FNP-ICA required the least amount of monoclonal antibody and had the best coefficients of variation. Additionally, FNP-ICA and EuNP-ICA had wider linear ranges and showed better tolerance than GNP-ICA and QD-ICA during detection. The present study developed FNP-ICA and EuNP-ICA with potential applications for the detection of pathogens in milk. https://doi.org/10.3168/jds.2017-12554.
Short communication: Nutrient consumption patterns of Lactobacillus acidophilus KLDS 1.0738 in controlled pH batch fermentations. By Lv et al., page 5188. We evaluated the consumption patterns of 33 nutritional components of Lactobacillus acidophilus KLDS 1.0738 with biomass and average growth rate. Considering consumption amount and rate, the most abundantly consumed amino acids, vitamins, ions, purines, and pyrimidines were glutamic acid, glycine, asparagine, and arginine, pyridoxine, nicotinamide, and folic acid, K+, PO43−, Fe2+, and Mn2+, guanine, uracil, and thymine, respectively. The overall consumption of glucose, adenine nucleotides, 2’-deoxyguanosine monohydrate, calcium pantothenate, Fe2+, and Mn2+ decreased with increasing average growth rate, indicating more efficient use of these nutritional components at higher average growth rate, as biomass yield based on nutritional components consumption increased. https://doi.org/10.3168/jds.2017-12607. Short communication: Effect of whey protein addition and transglutaminase treatment on the physical and sensory properties of reducedfat ice cream. By Danesh et al., page 5206. Scientific evidence supports the role of obesity in development of diseases such as diabetes mellitus type 2, coronary artery disease, and certain type of cancers. This evidence has promoted consumers to increasingly opt for reduced-fat foods. However, development of reducedfat foods including reduced-fat ice cream is challenging because fat plays a major role in their desirable sensory profiles. Enzymatic incorporation of whey proteins into milk into the formulation of reduced-fat ice cream by transglutaminase is an effective strategy to overcome problems associated with fat reduction. https://doi.org/10.3168/jds.2016-12537. Short communication: Production of cottage cheese fortified with vitamin D. By Crevier et al., page 5212. Vitamin D–fortified cottage cheese was obtained by a simple and effective method. Vitamin D was added together with cream at the end of cheese manufacture, which allowed accurate fortification of the cheese with vitamin D, because no vitamin D was lost in the cheese whey. Moreover, the vitamin D concentration in the cottage cheese remained stable throughout 3 wk of storage. In conclusion, cottage cheese could be considered a new source of vitamin D or an alternative to the vitamin D in drinking milk. https://doi.org/10.3168/jds.2016-12308. Effect of fat content on physical properties and consumer acceptability of vanilla ice cream. By Rolon et al., page 5217. Fat plays an important role in ice cream; it is a flavor delivery system and it provides
structural support. However, fat also contributes significantly to the caloric content of ice cream and consumers want alternative products with reduced energy density. This study investigated selected physical properties and consumer acceptability of vanilla ice cream in which fat was replaced with maltodextrin. Consumer acceptability did not change when fat was reduced from 14 to 6% using maltodextrin as a direct replacement to keep total solids constant. These data suggest that manufacturers may be able to substantially reduce energy content without compromising product acceptability. https://doi.org/10.3168/jds.2016-12379. Effects of replacement of late-harvested grass silage and barley with early-harvested silage on milk production and methane emissions. By Cabezas-Garcia et al., page 5228. An experiment was conducted to study the effects of replacement of late-cut silage and barley with early-cut silage on performance, N utilization efficiency, and methane emissions in dairy cows. The results indicate that it is feasible to reduce concentrate supplementation by improvements in forage quality without compromising animal performance, CH4 emissions or N efficiency. Milk protein yield decreased, but feed efficiency improved with increasing proportion of early-cut silage in the diet. Grass harvesting time for ensiling is crucial to maximize forage quality and reduce feed cost associated with increased concentrate supplementation. https://doi.org/10.3168/jds.2016-12444. Amino acid composition of rumen bacteria and protozoa in cattle. By Sok et al., page 5241. Microbial crude protein (MCP) contributes to more than 50% of the protein digested in the small intestine in cattle. Assuming that duodenal MCP flow comprises 33% fluid-associated bacteria (FAB), 50% particleassociated bacteria, and 17% protozoa, the amino acid (AA) composition of MCP was updated after an exhaustive literature review. Using these AA concentrations decreased supply estimates of methionine, threonine, and valine originating from MCP and increases those of lysine, and phenylalanine by 5 to 10% compared with those calculated with the AA composition of FAB that is commonly used. Furthermore, acknowledging that hydrolysis of 1 kg of true microbial protein yields 1.16 kg of free AA substantially increased the estimates of AA supply from MCP. A better estimate of AA supply from MCP should improve balancing of cattle rations for AA and would result in decreased feed cost and nitrogen excretion into the environment. https://doi.org/10.3168/jds.2016-12447. Using brown midrib 6 dwarf forage sorghum silage and fall-grown oat silage in lactating dairy cow rations. By Harper et al., page 5250. Dairy farmers may benefit from alternative forages in their crop-
ping strategies by increasing and stabilizing their annual forage yield. Sorghum can provide a rotation crop for corn, and oats utilize the fall growing season. In this experiment, sorghum or oat silages replaced corn silage at 10% of diet dry matter. Sorghum silage decreased dry matter intake and milk yield but increased milk fat percent to maintain energy-corrected milk yield, whereas oat silage maintained dry matter intake and production compared with the control. Sorghum and oat silage have potential for use in high-producing dairy cow rations at limited inclusion levels to increase dairy farm sustainability. https://doi.org/10.3168/jds.2017-12552. Effects of dietary energy allowance and decline in dry matter intake during the dry period on responses to glucose and insulin in transition dairy cows. By Salin et al., page 5266. Periparturient period is associated with insulin resistance in ruminants. A dramatic decrease in dry matter intake as a result of overfeeding during the dry period may impair wholebody insulin sensitivity, predisposing cows to metabolic disorders. Our study shows that overconsumption of grass silage compared with controlled intake of silage during the dry period did not affect glucose tolerance and insulin response to glucose in dairy cows during the transition period. https://doi.org/10.3168/jds.2016-11871. Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems. By Paula et al., page 5281. Canola meal increases milk production and N utilization in dairy cows when replacing soybean meal, the reasons for which may include ruminal and postruminal effects. Our objectives were to evaluate whether canola meal varying in rumen undegradable protein would affect ruminal metabolism and to compare these meals with soybean meal. Our results showed no major differences in ruminal digestibility or N metabolism among diets. Both canola meals produced less methane, suggesting that positive production responses previously observed may have been due to postruminal effects and dry matter intake. https://doi.org/10.3168/jds.2016-12301. Nutritive value and fermentation characteristics of alfalfa-mixed grass forage wrapped with minimal stretch film layers and stored for different lengths of time. By Coblentz et al., page 5293. Recently, the concept of inserting an O2-limiting barrier into commercial silage plastic wraps has been evaluated, yielding mixed or inconclusive results. Our objective for this study was to maximize the challenge to a commercial polyethylene bale wrap or an identical prototype wrap containing an O2-limiting barrier, by using
minimal plastic (4 layers) and then extending storage periods as long as 357 d. The cost of fermentation and storage across all bales within this study was a net loss of 2.2 total digestble nutrient (TDN) units, mostly occurring via loss of sugars through modest respiration. Insertion of an O2-limiting barrier into the plastic wrap had little effect on silage fermentation or postensiled nutritive value compared with a commercial plastic wrap managed in an identical manner. https://doi.org/10.3168/jds.2016-12404. Milk production and composition, nitrogen utilization, and grazing behavior of late-lactation dairy cows as affected by time of allocation of a fresh strip of pasture. By Vibart et al., page 5305. Timing of pasture strip allocation altered the herbage nutrient supply to cows. Despite partitioning similar amounts of nitrogen (N) towards urine, late-lactation dairy cows offered a daily fresh strip of pasture as a sole diet in the afternoon produced 8% more milk solids (milk fat + milk crude protein) than cows offered a morning strip. Allocating a fresh strip earlier in the day, however, resulted in a greater concentration of beneficial fatty acids in milk. https://doi.org/10.3168/jds.2016-12413. Effect of different fat supplements on performance of dairy calves during cold season. By Ghasemi et al., page 5319. During the cold season, feeding extra energy as fat might alleviate the negative effects of cold stress in young calves. In this study, we investigated the effects of supplementing fat (3%) and types of fatty acids in starters on calf performance during winter. Metabolizable energy intake tended to increase as a result of feeding tallow, soybean oil, or palm fat, but decreased when a mixture containing fish oil was fed. Although calf average daily gain tended to be enhanced by soybean oil, tallow had no beneficial effect on animal performance, and dietary inclusion of palm fat reduced feed efficiency in young calves. https://doi.org/10.3168/jds.2016-11827. Thiamine supplementation facilitates expression of thiamine transporters in rumen epithelium and attenuates high-grain-induced inflammation in low-yielding dairy cows. By Pan et al., page 5329. Overfeeding high grain (HG) diet to support high milk yield is common and is associated with a high incidence of inflammation. The objectives of this study were to determine whether an HG diet affected expression of thiamine transporters in rumen epithelium, and to evaluate the attenuation effects of thiamine on inflammation during HG feeding. The results showed that HG feeding decreased the mRNA expression of thiamine transporter 2 and mitochondrial thiamine pyrophosphate transporter, thiamine supplementation reduced the protein expression of TLR4 and the phos-
phorylation of NFκB unit p65, thereby inhibiting the protein expression of pro-inflammatory cytokines. In conclusion, thiamine could help attenuate inflammation under HG feeding. https://doi.org/10.3168/jds.2016-11966. Corn grain-processing method interacts with calcium salts of palm fatty acids supplementation on milk production and energy balance of early-lactation cows grazing tropical pasture. By Batistel et al., page 5343. We investigated the associative effects of feeding calcium salts of palm FA (CSPO) and methods of grain processing (fine ground and steam-flaked) on animal performance and energy balance of early-lactation dairy cows grazing on tropical pasture. Supplementation with CSPO and stem-flaked corn were effective strategies to increase energy intake and yields of milk and milk solids. The carryover effect on milk production was greater for CSPO supplementation than for steam-flaked corn; however, steam-flaked corn had lower mobilization of reserves and less body weight variation throughout lactation. Feeding CSPO increased dairy cow performance regardless of corn grain processing method but to a greater extent in less processed corn. https://doi.org/10.3168/jds.2016-12503. Effect of source of trace minerals in either forage- or by-product–based diets fed to dairy cows: 1. Production and macronutrient digestibility. By Faulkner and Weiss, page 5358. Carbohydrate source and trace minerals can influence microbial populations and alter nutrient digestibility; however, less is known regarding the interactions between these nutrients. Cows were fed forage- or byproduct-based diets with either hydroxy or sulfate Cu, Zn, and Mn sources. Total fecal and urine collections were conducted to determine apparent digestibility. Digestibility was different between the forage and byproduct diets and total digestible nutrients (TDN) were greater for the forage diet. Feeding hydroxy mineral increased neutral detergent fiber digestibility, but had no effect on TDN. Carbohydrate and mineral source affect digestibility and feeding increased byproducts can decrease dietary energy. https://doi.org/10.3168/jds.2016-12095. Effect of source of trace minerals in either forage- or by-product–based diets fed to dairy cows: 2. Apparent absorption and retention of minerals. By Faulkner et al., page 5368. Type of fiber can negatively influence mineral absorption in nonruminants; however, this has not been investigated in ruminants. Cows were fed forage- or byproduct-based diets with Cu, Mn, and Zn sources that were soluble in the rumen (sulfate salts) or less soluble in the rumen (hydroxy trace minerals). When cows were fed forage-
based diets, apparent absorption of Cu was greater for hydroxy minerals than for sulfate minerals but the opposite was true with byproduct diets, suggesting that antagonism may have occurred at different sites in the digestive system. Zinc absorption was not affected by treatment but Mn from the byproduct diets had greater absorption than Mn from the forage-based diets. https://doi.org/10.3168/jds.2016-12096. Association of aqueous hydrogen concentration with methane production in continuous cultures modulated to vary pH and solids passage rate. By Wenner et al., page 5378. Continuous culture fermenters enable testing of physiological treatments and their effects on methanogenesis, with absence of volatile fatty acid (VFA) absorption and predetermined passage rates. Buffer pH was decreased or solids passage rate was increased to challenge methanogen growth rates and shift hydrogen-producing VFA pathways according to a hypothesis on aqueous hydrogen thermodynamic control of VFA stoichiometry and methanogenesis. Increasing solids passage rate decreased methane production with minimal effects on nutrient digestibility. Lowering pH decreased acetate:propionate and increased valerate production, documenting increased production of VFA sinks for metabolic hydrogen. Results illustrate the complexity of controlling methanogenesis under in vivo-simulating conditions. https://doi.org/10.3168/jds.2016-12332. Abrupt weaning reduces postweaning growth and is associated with alterations in gastrointestinal markers of development in dairy calves fed an elevated plane of nutrition during the preweaning period. By Steele et al., page 5390. This study investigated feed intake, growth and biomarkers of gastrointestinal development in calves fed an elevated plane of nutrition that were either weaned abruptly or using a gradual (step-down) method. Although calves weaned with the gradual method showed reduced energy intake and growth preweaning, they displayed greater growth during weaning, which coincided with indicators of gastrointestinal development. Advancing our understanding of weaning strategies and dairy calf biology will aid in the development and implementation of sound early-life feeding strategies to improve animal performance and welfare. https://doi.org/10.3168/jds.2016-12310. The decline in digestive efficiency of US dairy cows from 1970 to 2014. By Potts et al., page 5400. Recent attention has been given to the improvement of feed efficiency in dairy cattle, and digestive ability plays an important role in a cow’s overall biological efficiency. Our analysis shows that the digestive efficiency of the US dairy cow has decreased between 1970 and 2014, even after accounting for concurrent changes in
diet composition. However, when feed intake was also accounted for, the decline in digestive efficiency over time was not significant. Despite reduced digestive efficiency, the modern dairy cow produces more milk per unit of feed digested than the 1970s dairy cow. https://doi.org/10.3168/jds.2017-12641. The use of mid-infrared spectrometry to estimate the ration composition of lactating dairy cows. By Klaffenböck et al., page 5411. Infrared spectrometry is routinely used to determine milk composition. In this study, we investigated the potential of infrared spectrometry to determine the feed ration composition of a lactating dairy cows. This may facilitate a cheap method of quality control for products like “grass-fed milk” or “silage-free milk.” The method applied creates promising estimations for some individual feedstuffs— pasture, concentrate, maize/grass silage—and several groups of feedstuffs. https://doi.org/10.3168/jds.2016-12189. Effect of different levels of rapidly degradable carbohydrates calculated by a simple rumen model on performance of lactating dairy cows. By Doorenbos et al., page 5422. Rate and extent of degradation of carbohydrates in the rumen of dairy cows differs within and between feedstuffs. Combining degradation characteristics of different carbohydrate components into rapidly degradable carbohydrates can simplify diet formulation. Increasing modeled dietary rapidly degradable carbohydrate level affected production performance. The results indicate that aggregating rapidly degradable carbohydrate content into one term may be a simple way to improve predictability of production responses in practical diet formulation for lactating dairy cows. https://doi.org/10.3168/jds.2016-12278. Effects of dietary crude protein concentration on late-lactation dairy cow performance and indicators of nitrogen utilization. By Barros et al., page 5434. Reducing crude protein (CP) from 16.2 to 14.4, 13.1, and 11.8% of dietary dry matter reduced performance and feed efficiency of late-lactation cows. However, time of response varied among variables depending on the size of the reduction. Analysis of data suggested no decline in yields of fat, protein, or milk until dietary CP declined below, 15.3, 16.2, or 15.5%, respectively. Milk protein yield was highly correlated with feed efficiency and daily yield of urea-N in milk. As dietary CP declined, cows performed better than predicted by the National Research Council model. https://doi.org/10.3168/jds.2016-11917. Effect of yeast supplementation on performance, rumination time, and rumen pH of dairy cows in commercial farm environments. By Ambriz-
Vilchis et al., page 5449. The use of live yeast as a feed additive is common practice in the dairy industry; however, research studies on the effect of live yeast on rumen function and performance have given variable results. Therefore, the aims of the present study were to evaluate the effects of live yeast supplementation on performance, rumination time, and rumen pH on dairy cows in a commercial farm environment in 3 trials: trial 1, a standard diet plus yeast; trial 2, an acidogenic diet plus yeast; and trial 3, grazing pasture plus yeast. No statistically significant differences were observed in any of the 3 trials for any of the recorded variables. No effect of live yeast supplementation was observed in any of the 3 trials reported in the present study. https://doi.org/10.3168/jds.2016-12346. Short communication: Associations between blood glucose concentration, onset of hyperketonemia and milk production in early lactation dairy cows. By Ruoff et al., page 5462. Hyperketonemia is a common disease in early lactating dairy cows and diagnosed by measurement of blood β-hydroxybutyric acid. It has been suggested that there are 2 types of hyperketonemia differing in their onset and their association with blood glucose concentration. Therefore, we investigated the occurrence of hypoglycemia and its association with hyperketonemia within the first 6 wk of lactation and evaluated the effects on milk production. https://doi.org/10.3168/jds.2016-12237. Short communication: Effect of a citrus extract in lactating dairy cows. By Harvatine et al., page 5468. Feed intake is important to meet the high energy demands of lactation. Two experiments were conducted to determine whether a citrus extract could increase intake and milk production in lactating dairy cows. The extract had no effect on milk production, dry matter intake, or feeding behavior. Plasma nonesterified fatty acids were decreased after feeding and some increases in plasma insulin were observed. At the tested dose, the extract had no effect on intake or milk production during the short-term treatments, but changes in insulin and nonesterified fatty acids were observed, which indicates some physiological effects that require further investigation. https://doi.org/10.3168/jds.2016-12233. Detection and assessment of copy number variation using PacBio long-read and Illumina sequencing in New Zealand dairy cattle. By Couldrey et al., page 5472. To date, genomic selection in dairy cattle has only utilized very small DNA sequence variations. The exclusion of larger sequence variations, such as copy number variations (CNV) that account for a considerable proportion of genetic variation, is largely due to difficulties in detection and measurement. Here, we describe the detection of CNV from long-read sequencing and validation of these CNV using short-read
sequencing. By combining data from these sequencing platforms together with pedigree information, we are able to identify CNV that truly segregate in the population. This represents a first step in including CNV in genomic selection strategies. https://doi.org/10.3168/jds.2016-12199. Accuracy of genomic predictions in Gyr (Bos indicus) dairy cattle. By Boison et al., page 5479. The reliability of genomic predictions for dairy traits in Gyr (Bos indicus) was evaluated using 4 SNP marker panels. To increase the size of the reference population, genotyped cows were added to the bull reference population. On average, reliabilities of genomic breeding values were substantially higher than parent averages. Addition of genotyped cows to the reference population increased reliabilities. Reliabilities obtained with all 4 marker panels were similar. Genomic predictions could be implemented in Gyr with a reduced marker panel of ~15,000. https://doi.org/10.3168/jds.2016-11811. Bovine mammary gland X chromosome inactivation. By Couldrey et al., page 5491. Female mammals have 2 X chromosomes, whereas males have a single X chromosome. In order to ensure equivalent gene expression, one of the female X chromosomes is inactivated during embryonic development. In dairy cattle breeding and genomic prediction, the implications of X chromosome inheritance and inactivation are particularly important given the small number of bulls passing their single X chromosome to all of their daughters. This paper describes X chromosome inactivation in lactating mammary glands and represents an initial step in ensuring that X chromosome variation is utilized in an appropriate manner for future genomic selection in dairy cattle. https://doi.org/10.3168/jds.2016-12490. Genetics of alternative definitions of feed efficiency in grazing lactating dairy cows. By Hurley et al., page 5501. Feed accounts for a large proportion of variable costs in dairy production systems. This study was performed to estimate genetic parameters and quantify the genetic interrelationships among alternative definitions of feed energy efficiency in lactating cows. Results from this study suggest that exploitable genetic variation exists for a range of efficiency traits, and the magnitude of this variation is sufficiently large to justify consideration of the feed efficiency complex in future dairy breeding goals. https://doi.org/10.3168/jds.2016-12314. Analysis of copy number variations in HolsteinFriesian cow genomes based on whole-genome sequence data. By Mielczarek et al., page 5515. We analysed whole-genome DNA sequences of 32 cows with a goal of detecting copy number variants (CNV),
which represent large structural variation in genomes. Compared with the reference genome, CNV can represent either duplication or deletion events. We observed considerable variation in length and number of CNV between individuals. By annotating a beginning and an end of each CNV to genomic regions, we observed that the majority of such breakpoints was located within intergenic regions and introns; fewer were identified within non-coding transcripts and splice regions. Only 1.24% (deletions) and 0.79% (duplications) breakpoints were found within coding regions. https://doi.org/10.3168/jds.2016-11987. Genetic parameters of measures and populationwide infrared predictions of 92 traits describing the fine composition and technological properties of milk in Italian Simmental cattle. By Bonfatti et al., page 5526. Mid-infrared spectroscopy is a valid tool for predicting several innovative milk traits that, according to the predictive ability of the models, might be used for breeding purposes. This study investigated the genetic relationship between measured and predicted traits, in order to evaluate the potential use of the infrared predictions of 92 technological and nutritional milk quality traits as indicator traits for selective breeding. https://doi.org/10.3168/jds.2016-11667. The genetics of antibody response to paratuberculosis in dairy cattle. By Pritchard et al., page 5541. Reducing paratuberculosis incidence in dairy cattle is not only of economic importance to dairy industries worldwide but essential in accounting for the societal and environmental considerations, such as the possible link with Crohn’s disease in humans, animal welfare, and greenhouse gas emissions. Testing cattle for paratuberculosis is important for its use in control programs and although the heritability of antibody response was low, breeding against the disease might be a good prospect as a preventative measure to assist together with other approaches in an overall control strategy. https://doi.org/10.3168/jds.2016-12300. The creation and evaluation of a model predicting the probability of conception in seasonalcalving, pasture-based dairy cows. By Fenlon et al., page 5550. Reproductive performance is a fundamentally important component of pasture-based dairy production systems. This study analyzed phenotypic and genetic factors to develop a predictive model of conception to any given service in seasonal-calving dairy cows in Ireland. Prediction models were externally evaluated using calibration and discrimination methods. A model including parity, calving difficulty, days since last service, genetics, day of lactation, and body condition score was found to most reliably predict the probability of conception. This model is of value
as a tool for farmer decision-support and stochastic simulation. https://doi.org/10.3168/jds.2016-11830. Genetic and nongenetic factors contributing to differences in αS-casein phosphorylation isoforms and other major milk proteins. By Fang et al., page 5564. Relative concentrations of αS-casein (CN) phosphorylation isoforms vary considerably among milk of individual cows. We showed that relative concentrations of αS-CN phosphorylation isoforms and the phosphorylation degree of αS-CN changed during and between lactations. Genetic variation among cows also contributes to the variation in relative concentrations of αS-CN phosphorylation isoforms and the phosphorylation degree of αS-CN. Therefore, changing phosphorylation degree of αS-CN in milk is possible by selective breeding. https://doi.org/10.3168/jds.2016-12338. Genetic parameters of mid-infrared methane predictions and their relationships with milk production traits in Holstein cattle. By Kandel et al., page 5578. This study aims mainly to estimate the genetic parameters of the daily methane (CH4) emission and intensity predicted from milk mid-infrared (MIR) spectrometry as well as their genetic correlations with the milk production traits in dairy cows. The MIR CH4 intensity was log-transformed to be normally distributed. Heritability values of MIR CH4 proxies were moderate, suggesting a CH4 genetic component. Relative increases of MIR CH4 were lower with high milk production levels, indicating that higher producing cows could be a mitigation option for CH4 emission. https://doi.org/10.3168/jds.2016-11954. Prevalence of non-aureus staphylococci species causing intramammary infections in Canadian dairy herds. By Condas et al., page 5592. Non-aureus staphylococci (NAS) are the most frequently isolated microorganisms from bovine udder quarters. Overall, 6.3% of 98,233 milk samples from 5,149 cows and 20,305 quarters in 91 Canadian dairy herds were NASpositive. The five most common NAS species of the 5,434 samples confirmed as NAS were Staphylococcus chromogenes (48.9%), Staphylococcus simulans (16.8%), Staphylococcus xylosus (11.6%), Staphylococcus haemolyticus (7.9%), and Staphylococcus epidermidis (4.1%). Individual NAS species associated with intramammary infections (IMI) were mostly prevalent in heifers after calving, particularly S. chromogenes, with similar prevalence among udder quarters for the most common NAS species. Differences across regions were linked to housing type, and NAS species were more prevalent in high bulk milk somatic cell count herds. https://doi.org/10.3168/jds.2016-12478.
Distribution of non-aureus staphylococci species in udder quarters with low and high somatic cell count, and clinical mastitis. By Condas et al., page 5613. Non-aureus staphylococci (NAS) are frequently isolated from quarter milk samples, and considered minor udder pathogens. In a cohort study on 91 Canadian dairy farms, somatic cell count (SCC) of NAS intramammary infection as a group was higher than that in culture-negative quarters, but lower than in major pathogen-positive quarters. Additionally, average quarter SCC of samples culture-positive for Staphylococcus capitis, Staphylococcus gallinarum, Staphylococcus hyicus, Staphylococcus simulans, and Staphylococcus chromogenes was higher than NAS as a group. Prevalence of the 12 most common NAS was higher in high- versus low-SCC samples. Staphylococcus sciuri was the most frequently isolated NAS in clinical mastitis samples. https://doi.org/10.3168/jds.2016-12469. Comparison of the efficacy of a commercial footbath product with copper sulfate for the control of digital dermatitis. By Jacobs et al., page 5628. Footbaths are a common control method for digital dermatitis (DD); however, the most commonly used footbath products have negative environmental and health consequences. Therefore, novel footbath products are being manufactured to replace potentially harmful products. An intervention trial was conducted on 19 dairy farms to evaluate the effectiveness of a novel footbath product in control of DD compared with the most commonly used product as well as typical on-farm footbath protocols. The novel product was inferior to the commonly used footbath product as well as typical footbath protocols. https://doi.org/10.3168/jds.2016-12257. The association between daily average feeding behaviors and morbidity in automatically fed group-housed preweaned dairy calves. By Knauer et al., page 5642. This prospective observational study was conducted on 10 farms in Minnesota and Virginia from February to October 2014 to explore the relationship between morbidity and daily average feeding behaviors in group-housed, automatically fed, preweaned dairy calves. A matched pair analysis revealed that calves changed some behaviors up to 4 d before they were found to be ill and were treated by a human observer. However, not all feeding behaviors were affected, and differences varied by disease diagnosed. Results suggest that some daily average feeding behaviors have potential to be a useful predictor or indicator of disease onset. https://doi.org/10.3168/jds.2016-12372. Quarter- and cow-level risk factors for intramammary infection with coagulase-negative staph-
ylococci species in Swiss dairy cows. By Dolder et al., page 5653. This longitudinal study investigated potential risk factors for an intramammary infection with coagulase-negative staphylococci species in Swiss dairy cows. The 4 most prevalent species were analyzed individually and others were analyzed jointly. Except for co-infection, no quarter-level risk factors were identified. Instead, most of the significant risk factors were at the cow level. https://doi.org/10.3168/jds.2016-11639. Machine-learning-based calving prediction from activity, lying, and ruminating behaviors in dairy cattle. By Borchers et al., page 5664. Frequent visual inspection has long served as the primary method to identify cattle in labor. Monitoring behavior using precision dairy technologies before calving could be used to predict calving. This study quantified cow activity, time spent ruminating, and lying behaviors before calving and applied machine-learning methods to retrospectively determine the calving prediction efficacy of these variables. A combination of activity, rumination time, and lying behaviors in prediction models was effective in predicting calving and shows promise in future research and commercial applications. https://doi.org/10.3168/jds.2016-11526. Factors associated with dairy calf health in automated feeding systems in the Upper Midwest United States. By Jorgensen et al., page 5675. Dairy calves are increasingly being raised using automated feeding systems, but there is little information available about how these systems are managed or how this management affects calf health outcomes. This study describes calf health on farms using automated feeders and identifies risk factors for adverse health outcomes. Season, stocking and feeding practices, and bacterial contamination of the milk were associated with animal health in these systems. Producers may be better able to raise healthier calves, reduce economic losses related to calf illness, and improve calf welfare in automated feeding systems by changing management practices in the identified areas. https://doi.org/10.3168/jds.2016-12501. Effect of circulating exosomes from transition cows on Madin-Darby bovine kidney cell function. By Crookenden et al., page 5687. Exosomes are long-distance, intercellular communication systems that deliver RNA and proteins to target cells that are representative of the functional state of their tissue of origin; as such, they are important regulators of cellular metabolism. Exosomes from the plasma of 2 groups of transition dairy cows characterized as at either high or low risk of metabolic dysfunction during the transition period were isolated and co-cultured with bovine kidney cells. Gene expression and proteomics were used
to investigate their effect on target cell function. There were no statistically significant changes associated with the metabolic state of the cows sampled; however, gene expression changes were consistent with greater cell proliferation and immunomodulation in high-risk cows compared with low-risk cows, and protein signatures were consistent with altered cellular function with the treatment of exosomes. Further investigation is required with larger numbers of animals to confirm these preliminary data. https://doi.org/10.3168/jds.2016-12152. Effects of different sources of Saccharomyces cerevisiae biomass on milk production, composition and aflatoxin M1 excretion in milk from dairy cows fed aflatoxin B1. By Gonçalves et al., page 5701. We evaluated different sources of Saccharomyces cerevisiae biomass on milk production, composition and aflatoxin (AF)M1 excretion in milk from dairy cows fed AFB1. Results indicate a potential application of industrial fermentation by-products containing yeast cells, especially cell wall and autolyzed yeast, in reducing the bioavailability of AFB1 in the diets of dairy cows and the excretion of AFM1 in milk. https://doi.org/10.3168/jds.2016-12215. DNA carryover in milk samples from routine milk recording used for PCR-based diagnosis of bovine Staphylococcus aureus mastitis. By Mahmmod et al., page 5709. Our study demonstrates that carryover of Staphylococcus aureus DNA between consecutively milked cows occurs and affects PCR test results from non-aseptically-collected composite samples at milk recording. The odds of being PCR test positive increased with increasing concentration of Staph. aureus DNA in the milk of the antecedent cow, measured in PCR cycle threshold (Ct) values. We propose grouping cows into 3 categories: very likely infected cows (Ct-value <32), very likely uninfected cows (Ct-value 37–40), and cows of uncertain status (Ct-value 32–36), in which retests or supplemental tests are necessary to differentiate between carryover and low shedding. https://doi.org/10.3168/jds.2016-12330. Short communication: Repeatability of β-hydroxybutyrate measurements in capillary blood obtained from the external vulvar skin. By Iwersen et al., page 5717. The primary objective of this study was to evaluate the repeatability of β-hydroxybutyrate measurements in capillary blood obtained from different sites at the skin of the external vulva of dairy cows. The second objective was to validate a successor version of a handheld device for β-hydroxybutyrate measurements in capillary blood at the vulva. In summary, the repeatability of measurements was good and after threshold adjustment the handheld device was eligible to detect hyperketonemia. https://doi.org/10.3168/jds.2016-12011.
Short communication: Detection and monitoring of metritis in dairy cows using an automated grooming device. By Mandel et al., page 5724. Use of automated systems to detect morbidity in dairy cows is increasing. Current systems detect changes in behaviors that are essential for the short-term survival of the animal (e.g., rumination, lying). The objective of this study was to evaluate the efficacy of monitoring brush usage (“low-resilience” activity) in the early detection of metritis. Cows with metritis used the brush less than control cows during 8 to 28 d postpartum (i.e., week of clinical diagnosis and weeks of medical treatment). These findings suggest that brush usage has potential to be developed as an early warning indicator of health problems in dairy cows. https://doi.org/10.3168/jds.2016-12201. Comparison between an exclusive in vitro–produced embryo transfer system and artificial insemination for genetic, technical, and financial herd performance. By Kaniyamattam et al., page 5729. Transfer of in vitro-produced embryos (IVP-ET) from oocytes of the genetically best females to impregnate other females in the herd allows for rapid genetic progress. Cost of the IVP-ET system per transfer is greater than the cost of an artificial insemination. We developed a model that includes multi-trait genetics to study genetic, technical, and financial differences between an exclusive IVP-ET system and an artificial insemination system. Results showed that the exclusive IVP-ET system may be of commercial interest to dairy farmers in some situations. https://doi.org/10.3168/jds.2016-11979. Farmers’ preferences for automatic lameness detection systems in dairy cattle. By Van De Gucht et al., page 5746. This study elucidated dairy farmers’ preferences for automatic lameness detection systems using a discrete choice experiment in a survey. The number of false alarms and undetected lame cows, system cost, and the ability to determine which leg is lame significantly influenced the usefulness that farmers attached to a detection system. On average, farmers did not prefer automatic systems over visual lameness detection. Farmers’ preferences changed after providing more information about the consequences of lameness. Socio-demographic parameters such as the importance farmers attached to lameness, whether they use automatic estrus detection, and the interval from calving to first insemination also influenced preferences significantly. https://doi.org/10.3168/jds.2016-12285. Multivariate dynamic linear models for estimating the effect of experimental interventions in an evolutionary operations (EVOP) setup in dairy herds. By Stygar et al., page 5758. Using evolutionary operations (EVOP), a farm manager conducts experi-
ments during production in order to improve the production process and ultimately farm profitability. The goal of this study was to help farmers assess the effect of these experimental interventions. For this purpose, we constructed and tested a decision support tool. The tool was used in herds where farm managers wanted to explore how changes in feeding strategies influence the milk yield. The tool proved to be useful in identifying the effect of intervention on the milk yield and it could be used for on-farm optimization. https://doi.org/10.3168/jds.2016-12251. Colostrum immunoglobulin G concentration of multiparous Jersey cows at first and second milking is associated with parity, colostrum yield, and time of first milking, and can be estimated with Brix refractometry. By Silva-del-Río et al., page 5774. To achieve adequate immune protection from maternal antibodies, mostly immunoglobulin (Ig)G, newborn calves are required to be fed with good quality colostrum. We showed that colostrum IgG concentrations from multiparous Jersey cows wer associated with dam’s lactation number, colostrum yield, and time of first milking relative to calving. Further, readings of Brix refractometry were shown to be a good tool to rapidly estimate IgG concentration on Jersey colostrum harvested at first and second milking. https://doi.org/10.3168/jds.2016-12394. Effect of inhibiting the lactogenic signal at calving on milk production and metabolic and immune perturbations in dairy cows. By Vanacker et al., page 5782. In the days following calving, the rapid increase in nutrient demands to support milk production often results in metabolic and immunological disturbances in dairy cows. In the present experiment, we tested the hypothesis that slowing down the increase in milk production using the prolactin-release inhibitor quinagolide decreases metabolic and immunological disturbances. The results show that quinagolide temporarily decreases milk production, leading to an improvement in the metabolic profile and in some aspects of the immune system of cows. https://doi.org/10.3168/jds.2017-12570. Effect of conjugated linoleic acid and acetate on milk fat synthesis and adipose lipogenesis in lactating dairy cows. By Urrutia and Harvatine, page 5792. The role of trans-10,cis-12 conjugated linoleic acid (CLA) and spared nutrients from milk fat synthesis on adipose tissue lipogenesis during milk fat depression is not clear. This study showed that in low-producing cows, adipose tissue was sensitive to the anti-lipogenic effects of CLA during CLA-induced milk fat depression. However, acetate infusion mimicking the amount spared during milk fat depression did not stimulate adipose lipogenesis but increased milk fat yield under normal milk fat conditions. https://doi.org/10.3168/jds.2016-12369.
Use of calcitriol to maintain postpartum blood calcium and improve immune function in dairy cows. By Vieira-Neto et al., page 5805. Objectives were to determine the effects of an injectable formulation of calcitriol on mineral metabolism and measures of immune function in Holstein cows. Calcitriol increased blood concentration of ionized Ca, and plasma concentrations of total Ca and total P, whereas reduced total Mg compared with control cows. Calcitriol increased urinary excretion of total Ca and Mg in the first week postpartum. Calcitriol did not affect production performance in the first 36 d in milk, but it improved measures of innate immune function. Administration of calcitriol at calving increased blood concentrations of Ca and P postpartum and improved immune function. https://doi.org/10.3168/jds.2016-12506. Sperm viability, reactive oxygen species, and DNA fragmentation index combined can discriminate between bulls with above- and belowaverage fertility. By Kumaresan et al., page 5824. The accurate prediction of bull fertility is of major economic importance in the dairy breeding industry. We identified a suitable combination of sperm attributes that could be used to discriminate bulls with belowaverage fertility from those with above-average fertility. A model was developed for predicting bull fertility with a high degree of accuracy. Researchers and companies involved in dairy breeding may find it useful for bull fertility prediction. https://doi.org/10.3168/jds.2016-12484. miR-26b promoter analysis reveals regulatory mechanisms by lipid-related transcription factors in goat mammary epithelial cells. By Wang et al., page 5837. MicroRNA-26b (miR-26b), which is localized in the introns of C-terminal domain RNA polymeraseⅡpolypeptide A small phosphatase 1 (CTDSP1) gene, is a key miRNA that regulates triacylglycerol synthesis by suppressing insulin induced gene 1 in goat mammary epithelial cells. To explore the regulatory mechanism of goat miR-26b by lipid-related transcription factors, including peroxisome proliferatoractivated receptor gamma (PPARG), sterol regulatory element binding transcription factor 1 (SREBF1), and liver X receptor α (LXRα), we cloned and constructed luciferase reporter vectors of the miR-26b gene promoter. Site-directed deletion analysis revealed that these transcription factors could potently promote the transcription of miR-26b through binding to PPRE and SRE sites on the goat miR-26b promoter. Bisulfite genomic sequencing PCR sowed that overexpression of these transcription factors decreased miR-26b promoter methylation, indicating that miR-26b is regulated by transcription factors dually through DNA methylation and directly through binding to its promoter, all of which implies that regulation of miR-26b in ruminant
mammary epithelial cells results from various mechanisms. https://doi.org/10.3168/jds.2016-12440.
milk content, and derives from the conversion of 47 to 50% of stearic acid. https://doi.org/10.3168/jds.2016-12097.
Milk protein concentration, estimated breeding value for fertility, and reproductive performance in lactating dairy cows. By Morton et al., page 5850. Milk protein concentration is positively associated with a range of measures of reproductive performance in dairy cows and it is possible that genetic factors affecting both milk protein concentration and reproductive performance contribute to the observed phenotypic associations. Genetic effects, measured using estimated breeding values for fertility, did not account for the association between milk protein concentration and reproductive performance. If the causes of that association can be determined and utilized through management changes, then beneficial effects on reproductive performance would be expected over and above those due to increased breeding value for fertility alone. https://doi.org/10.3168/jds.2016-11273.
Effect of pre- and postpartum supplementation with lipid-encapsulated conjugated linoleic acid on reproductive performance and the growth hormone–insulin-like growth factor-I axis in multiparous high-producing dairy cows. By Csillik et al., page 5888. We evaluated reproductive performance and the growth hormone–insulin-like growth factor-I (GH–IGF-I) axis of dairy cows supplemented with conjugated linoleic acid (CLA). We demonstrated that dietary supplementation with CLA isomers results in a greater postovulatory P4 increase and fewer days from calving to conception. Higher plasma IGF-I and leptin levels can be important metabolic signals for follicle development and improved corpus luteum function; however, we did not find any effects of CLA isomers on hepatic GHR1A expression. https://doi.org/10.3168/jds.2016-12124.
The effect of dry period length and postpartum level of concentrate on milk production, energy balance, and plasma metabolites of dairy cows across the dry period and in early lactation. By van Hoeij et al., page 5863. This study evaluated the effects of dry period (DP) length and postpartum concentrate level on milk yield, feed intake, energy balance (EB), and plasma metabolites between 4 weeks prepartum and 7 weeks postpartum. Postpartum, a 0-d DP resulted in lower fat-and-protein-corrected-milk yield, plasma free fatty acids and β-hydroxybutyrate concentrations, and greater dry matter intake, EB, plasma glucose, insulin and insulin growth factor-1 concentrations compared with a 30-d DP, with a few exceptions, regardless of concentrate level. Lower energy intake of cows with a 0-d DP might reduce feed costs and the risk of over-conditioning, and is potentially beneficial for net herd returns. https://doi.org/10.3168/jds.2016-11703.
Postnatal phenotype of dairy cows is altered by embryo production in vitro using reverse Xsorted semen. By Siqueira et al., page 5899. Adult health depends upon maternal environment during gestation as early as the preimplantation period. Whether alterations in developmental programming associated with assisted reproductive techniques affect postnatal function is an important question because of the growing impact of these technologies. Here, we showed that embryo production in vitro with reverse X-sorted semen has consequences for dairy cattle that extend into adult life and reduce biological efficiency of food production. Females derived by in vitro embryo production using reverse sorted semen were different in important respects from females born following other procedures, including experiencing reduced milk production in first lactation. https://doi.org/10.3168/jds.2016-12539.
Endogenous synthesis of milk oleic acid in dairy ewes: In vivo measurement using 13C-labeled stearic acid. By Toral et al., page 5880. Despite the convenience of using isotopic tracers to investigate fatty acid metabolism in dairy ruminants, only a small number of studies have applied this methodology in cows and goats, and no reports are available in sheep. Therefore, this study provides the first assessment in dairy ewes of the uptake, Δ9-desaturation and secretion into milk of a stable isotope tracer, namely 13C-labeled stearic acid, with the aim of measuring in vivo endogenous synthesis of milk oleic acid and Δ9-desaturase activity. Results show that the proportion of oleic acid arising from Δ9-desaturation represents 48 to 57% of its total
Exogenous essential amino acids stimulate an adaptive unfolded protein response in the mammary glands of lactating cows. By Nichols et al., page 5909. Protein and gene expression were analyzed in muscle and mammary tissue of dairy cows given extra essential amino acids, with and without glucose, through abomasal infusion. The mammalian target of rapamycin complex 1 (mTORC1) regulatory pathway was up-regulated by amino acids in muscle but not in mammary glands. Instead, mammary tissue responded to amino acids by increasing expression of genes that stimulate biogenesis of the endoplasmic reticulum responsible for processing proteins destined for secretion into milk. Findings suggest that differentiation of the
secretory phenotype in mammary tissue is under nutritional control. https://doi.org/10.3168/jds.2016-12387. Short communication: A reproductive tract scoring system to manage fertility in lactating dairy cows. By Young et al., page 5922. A reproductive tract size and position scoring (SPS) system in lactating Holstein cows was developed. Its use to identify less fertile cows provides the dairy producer the opportunity to make meaningful management decisions. In cases where culling is not desirable, use of less expensive semen or that available from high-conception-rate bulls may be warranted. https://doi.org/10.3168/jds.2016-12288. Short communication: Comparative proteomic analysis of the lactating and nonlactating bovine mammary gland. By Dai et al., page 5928. This study presents a proteomic analysis of the changes occurring in the mammary gland during lactation. The analysis suggests comprehensive changes in protein abundance associated with macromolecular metabolic processes, milk synthesis and secretion, and lactation. Thus, this study will provide protein-related insight into bovine mammary gland during lactation. https://doi.org/10.3168/jds.2016-12366. Effects of rare sugar d-allulose on acid production and probiotic activities of dairy lactic acid bacteria. By Kimoto-Nira et al., page 5936. Rare sugar d-allulose has beneficial effects on human health, and can be substituted for sucrose as a low-calorie food ingredient. To examine the applications of d-allulose in the dairy industry, the effects of d-allulose on the acid production and probiotic activity of dairy lactic acid bacteria were investigated. The acid production of certain lactic acid bacteria in milk was affected by dallulose. Probiotic activity such as antioxidant activity was not altered by this sugar. This sugar could be used to regulate acid production in overfermented milk that would have a highly intense sour taste without altering their probiotic activity. https://doi.org/10.3168/jds.2016-12214. Lactation performance of Holstein cows treated with 2 formulations of recombinant bovine somatotropin in a large commercial dairy herd in Brazil. By de Morais et al., page 5945. This study compared milk yield and composition throughout a full lactation cycle for Holstein cows treated with 2 rbST
formulations. For both primiparous and multiparous cows, the zinc sesame oil-based rbST treatment was better than the vitamin E lecithin-based rbST treatment in terms of milk yield because of its more sustained effect between rbST injections. Results contribute to the information available on rbST that can be used by dairy producers to select a suitable rbST formulation for use in their herds in countries where both products are available. https://doi.org/10.3168/jds.2016-11965. Effect of feeding strategies and cropping systems on greenhouse gas emission from Wisconsin certified organic dairy farms. By Liang et al., page 5957. This study evaluated the greenhouse gas emissions resulting from different feeding strategies used by Wisconsin certified organic dairy farms. Integrating pasture as a feed production strategy can contribute to mitigation of carbon losses from soil compared with annual crops. Feeding strategies and grazing management both influence milk production as well as carbon footprint. https://doi.org/10.3168/jds.2016-11909. Host-mediated effects of phytonutrients in ruminants. By Oh et al., page 5974. Phytonutrients have had limited effect on microbial fermentation in the rumen. However, recent studies have provided evidence that phytonutrients exhibit receptor-mediated physiological effects in host animals including immune responses, oxidative stress status, and insulin regulation, which may positively affect productivity in dairy cows. https://doi.org/10.3168/jds.2016-12341. Understanding the gut microbiome of dairy calves: Opportunities to improve early-life gut health. By Malmuthuge and Guan, page 5996. This review focuses on the knowledge of calf gut microbiota, the impact of antimicrobial treatments on the gut microbiota, and the use of early dietary interventions to manipulate the gut microbiota for the improvement of calf health. Early dietary interventions through redirecting the microbiota, such as microbial supplements, show promising results by decreasing incidence of diarrhea and by promoting calf growth. Studying the mechanisms behind such interventions is necessary in the future to design effective microbial manipulation tools that improve the gut health and overall host health through manipulation of gut microbiota. https://doi.org/10.3168/jds.2016-12239.