Other| Volume 97, ISSUE 11, Pix-xvi, November 2014

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Interpretive summaries, November 2014

        Invited review: Animal-based indicators for onfarm welfare assessment for dairy goats. By Battini et al., page 6625. Consumer demand for assurance schemes of high-quality animal products, including aspects of animal welfare, has increased over the last few decades. In response to this demand, animal welfare assessment at the farm level is presently one of the most debated issues in the field of animal husbandry. We have reviewed the existing literature to identify animal-based indicators that can be included in a welfare assessment protocol for dairy goats and we discuss the validity, reliability and on-farm feasibility of said indicators. This protocol may be used by farmers for internal evaluation or by veterinarians and technicians for certification purposes.
        Invited review: Antibiotic treatment of metritis in dairy cows: A systematic approach. By Haimerl and Heuwieser, page 6649. A systematic and evaluative literature review revealed a dearth of studies on the treatment of acute puerperal metritis. However, the quality of the studies was good. Despite the prevalent concerns regarding increasing bacterial resistance, the implementation of bacteriological examinations, sensitivity testing, determination of minimum inhibitory concentrations, and reporting and discussion of critical issues (e.g., self-cure rates, resistance, prudent drug use) were suboptimal. Hence, more high-quality research is necessary to address critical issues related to acute puerperal metritis, such as accuracy of diagnostic methods, resistance, prudent use of antibiotics, animal welfare, and cost-benefit ratios.
        Antioxidant activity of yogurt made from milk characterized by different casein haplotypes and fortified with chestnut and sulla honeys. By Perna et al., page 6662. The antioxidant activity of yogurt is strongly affected by antioxidant peptides that develop during fermentation of the milk by lactic acid bacteria, and the release of these peptides is affected by casein haplotype of milk. The addition of fruit or honey to yogurt is widely used to improve its organoleptic characteristics and nutritional value. Honey is a functional food rich in nutraceutical components such as vitamins, phenolic acids, and flavonoids. The antioxidant activity of honey is associated with the presence of these nutraceutical compounds; therefore, the addition of honey to yogurt should affect the antioxidant power of the obtained product. This work highlights the antioxidant activity of yogurt made from milk characterized by different casein haplotypes (αS1-, β-, κ-caseins) and fortified with sulla and chestnut honeys, in order to demonstrate that milk protein polymorphisms and polyphenols play different roles in affecting the bioavailability and antioxidant activity of yogurt.
        Evaluation of NaCl, pH, and lactic acid on the growth of Shiga toxin-producing Escherichia coli in a liquid Cheddar cheese extract. By Oh et al., page 6671. A Cheddar cheese model system, Cheddar cheese extract (CCE), was applied to identify key compositional factors in cheese affecting growth and survival of pathogenic bacteria. We determined that Shiga toxin-producing Escherichia coli (STEC) strains survived longer than other foodborne pathogenic bacteria examined (Salmonella, Listeria monocytogenes, and Staphylococcus aureus) in CCE simulating low- Na Cheddar cheese. Additionally, we found that pH in CCE is the primary determinant of STEC survival. This study reports levels of critical factors that must be achieved to produce a safe low-sodium cheese.
        Sensory analysis and species-specific PCR detect bovine milk adulteration of frescal (fresh) goat cheese. By Golinelli et al., page 6693. The adulteration with cow milk of frescal (fresh) cheeses labeled as goat cheese was detected in all tested goat cheeses (20) from 4 brands sold at retail in Rio de Janeiro. Adulteration was tested by DNA analysis of cheese composition, and the method was able to detect the addition of 0.5% (vol/vol) bovine milk. Nearly 50% of consumers tested were able to perceive the adulteration if >10% (vol/vol) bovine milk was added. The market for goat dairy products in Brazil should be regulated by considering the rights and choices of consumers according to their particular requirements for diet and health, preference, and cost.
        Evolution under different storage conditions of anomalous blue coloration of Mozzarella cheese intentionally contaminated with a pigmentproducing strain of Pseudomonas fluorescens. By Cenci-Goga et al., page 6708. Beginning in summer 2010, several large outbreaks of anomalous blue coloration of Mozzarella cheese were recorded in the United States and some European countries. The cause of the blue hue was traced to water tainted by a natural, nontoxic bacteria, Pseudomonas fluorescens, that came from contaminated groundwater. We have established a simple and inexpensive method to study the evolution of the blue coloration under different storage conditions and to help producers intercept contaminated batches.
        Total milk fat extraction and quantification of polar and neutral lipids of cow, goat, and ewe milk by using a pressurized liquid system and chromatographic techniques. By Castro-Gómez et al., page 6719. In this study, a pressurized liquid extraction procedure was proposed as a cheaper, faster, and safer method for milk fat extraction. It used a smaller volume of solvent mixtures to extract milk fat, and the time applied per sample was significantly less, with a high recovery of total lipids (especially polar lipids). This method offers the possibility of automation and could be an alternative routine method of milk fat extraction.
        Effect of microparticulated whey proteins on milk coagulation properties. By Sturaro et al., page 6729. The effect of increasing concentrations of aggregated whey proteins on milk coagulation properties was evaluated using a Formagraph. Rennet coagulation time and curd-firming time were unfavorably affected by high levels of whey proteins added to milk, whereas gel strength was not affected. The recovery of whey proteins depended on the specific fractions considered. Adjustments to coagulation time are required when aggregated whey proteins are used in the cheese-making process.
        Production and characterization of a tributyrin esterase from Lactobacillus plantarum suitable for cheese lipolysis. By Esteban-Torres et al., page 6737. Lipolysis of milk fat during cheese ripening is an important biochemical process that contributes directly to the sensorial characteristics of the cheese. Starter and nonstarter bacteria possess enzymes exhibiting esterase activity for milk fat hydrolysis. Lactobacillus plantarum is a nonstarter bacteria frequently isolated during cheese ripening. Lactobacillus plantarum possesses an esterase, Lp_1760, that is able to hydrolyze tributyrin, the simplest triglyceride occurring in natural fats. This esterase is active under conditions (e.g., temperature, pH, presence of NaCl and CaCl2) commonly found during cheese-making and ripening. Therefore, Lp_1760 tributyrin esterase is an useful esterase for cheese lipolysis.
        Comparative analysis of bacterial community composition in bulk tank raw milk by culturedependent and culture-independent methods using the viability dye propidium monoazide. By Weber et al., page 6761. We evaluated the viability dye propidium monoazide for application in direct cultureindependent analyses of the bacterial community of raw milk. The purpose of this approach was to allow selective detection of viable bacterial cells by direct DNA-based methods. This is an important step towards comparability between bacterial community composition depicted by culture-dependent and culture-independent methods and improves culture-independent investigations of bacterial community structure, which could lead to an almost complete picture of the bacterial composition of raw milk.
        Prevalence of thermoduric bacteria and spores on 10 Midwest dairy farms. By Buehner et al., page 6777. Raw milk and feed samples and swabs of milking equipment were collected from South Dakota dairy farms during winter and summer 2013. Samples were tested and profiled for heat-resistant (thermoduric) bacteria and those with the ability to form spores (spore-forming bacteria) that can persist in milk-processing environments and cross-contaminate raw milk. High concentrations of thermoduric bacteria, including sporeformers and non-spore-formers, were isolated from samples, with higher concentrations persisting during summer than in winter.
        Detection and prevalence of pathogenic Yersinia enterocolitica in refrigerated and frozen dairy products by a duplex-PCR and dot hybridization targeting the virF and ail genes. By Ye et al., page 6785. Pathogenic Yersinia enterocolitica is involved in yersiniosis through expression of virulence factors. Yersinia enterocolitica is a cold-tolerant pathogen frequently isolated from refrigerated or frozen food. In this study, we developed a duplex-PCR targeting the plasmid-borne virF gene and the chromosomeborne ail gene for simultaneous detection and prevalence of pathogenic Y. enterocolitica. Detection of Y. enterocolitica in pure culture, artificially contaminated dairy products, and commercial dairy products indicated that the duplex-PCR was reliable for large-scale screening, routine monitoring, and risk assessment of pathogenic Y. enterocolitica in refrigerated or frozen dairy products.
        Short communication: Viability of culture organisms in honey-enriched acidophilus-bifidusthermophilus (ABT)-type fermented camel milk. By Varga et al., page 6814. Probiotic fermented dairy foods containing bifidobacteria, Lactobacillus acidophilus, and Streptococcus thermophilus were produced from camel and, for comparison, from cow milks with and without addition of black locust honey. Honey improved retention of viability of bifidobacteria in the camel milk-based product during storage at 4°C for up to 5 wk. Fortification of cultured dairy products with honey is recommended because honey is a natural sweetener with a variety of beneficial microbiological, nutritional, and sensory properties. This is the first scientific study evaluating the growth and viability of bifidobacteria and lactic acid bacteria in honey-enriched fermented camel milk.
        Short communication: Monitoring nutritional quality of Amiata donkey milk: Effects of lactation and productive season. By Martini et al., page 6819. Quality of donkey milk during lactation and the productive season was monitored. Donkey milk yield, dry matter, fat, and ash contents were stable during lactation. Milk yield, casein, and lactose were higher in summer and autumn, whereas proteins, ash, and calcium were higher in spring; dry matter, and fat were stable. The stable quality of donkey milk is an advantage for production, trade, and consumption.
        Short communication: Development of a direct in vivo screening model to identify potential probiotic bacteria using Caenorhabditis elegans. By Park et al., page 6828. Caenorhabditis elegans is an accepted model host to study host–bacteria interactions in the gut, because these nematode worms possess similar intestinal environments to those of humans. Here, we developed a direct in vivo screening system using C. elegans to study host health-promoting lactic acid bacteria. Four strains of Lactobacillus plantarum were highly persistent in the nematode gut and significantly prolonged the longevity and improved the survival of C. elegans in response to infection by Staphylococcus aureus. Our direct in vivo C. elegans system is simple, rapid, cost-effective, and reliable, and we anticipate that this system will result in the discovery of many more potential probiotic bacteria for dairy foods.
        Designing a risk-based surveillance program for Mycobacterium avium ssp. paratuberculosis in Norwegian dairy herds using multivariate statistical process control analysis. By Whist et al., page 6835. Surveillance programs for animal infections are key to early detection. Identifying farms with a higher infection risk and targeting surveillance towards these herds will increase the probability of finding infected herds. The risk-based surveillance program described in this paper combined production and clinical data to identify herds with an assumed higher risk for Mycobacterium avium ssp. paratuberculosis infection. Multivariate statistical process control was applied to calculate risk and rank the herds accordingly. A riskbased surveillance program, preferably together with an increased number of samples, will improve surveillance of M. avium ssp. paratuberculosis in Norway.
        Temporary alterations to postpartum milking frequency affect whole-lactation milk production and the energy status of pasture-grazed dairy cows. By Phyn et al., page 6850. Milking cows once daily for 3 or 6 wk immediately postpartum reduced yields of milk, fat, and protein compared with twice-daily milking during (i.e., an immediate effect) the period of reduced milking frequency, and after cows were switched to twice-daily milking for the rest of lactation (i.e., a carryover effect). In comparison, milking cows thrice daily immediately increased milk yield, but carryover effects were not as prominent, and milk fat and protein yields were unaffected throughout. Furthermore, cow energy balance decreased with increasing milking frequency. Therefore, short-term changes to postpartum milking frequency affected whole-lactation production and energy status of pasture-grazed cows.
        An ex ante analysis on the use of activity meters for automated estrus detection: To invest or not to invest? By Rutten et al., page 6869. Estrus detection is an important factor in reproduction management on dairy farms. In order to automate and improve estrus detection, many studies have focused on developing sensor systems (e.g., activity meters) that can automatically detect estrus. In this study, we used a simulation model to estimate the technical effects (e.g., annual milk production and number of calves born per year) of using activity meters for estrus detection. Using these technical effects, financial consequences were estimated and used to appraise the investment in activity meters. In general, investment in activity meters was profitable.
        Plasma anti-Müllerian hormone in adult dairy cows and associations with fertility. By Ribeiro et al., page 6888. Associations between anti-Mülerian hormone (AMH) and measures of fertility in 1,237 grazing dairy cows subjected to a 100-d breeding season were investigated. We found no association between concentrations of AMH and pregnancy at the first artificial insemination (AI) performed after synchronized ovulation, but AMH was negatively associated with detection of estrus on the day of timed AI. Nonetheless, the concentration of AMH was associated positively with maintenance of pregnancy at the first AI and pregnancy rate in the remaining of the breeding season following insemination after detection of spontaneous estrus. Synchronization of ovulation might override positive associations between AMH and fertility.
        Blood calcium dynamics after prophylactic treatment of subclinical hypocalcemia with oral or intravenous calcium. By Blanc et al., page 6901. Low blood calcium is a common disease of dairy cows at calving with negative effects on health and milk yield. To evaluate the effects of supplementing oral or intravenous calcium to prevent this disease, cows in their third or greater lactation were assigned, after calving, to control (no calcium supplementation), intravenous calcium (intravenous administration of 500 mL of a calcium solution), or oral calcium (cows given 2 oral calcium boluses). Cows given intravenous calcium after calving initially had higher blood calcium levels but levels decreased to less than those of control or the oral-supplemented cows on the day after calving.
        Genetic relatedness and virulence factors of bovine Staphylococcus aureus isolated from teat skin and milk. By da Costa et al., page 6907. This study evaluated genetic relatedness of Staphylococcus aureus from teat skin and milk and the role of teat skin colonization in Staph. aureus intramammary infections. Isolates from teat skin and milk were closely related, with 72% belonging to one predominant cluster and harboring specific virulence factors that may have contributed to them becoming the dominant strain. Quarters with teat skin colonized with Staph. aureus were 4.5 times more likely to be diagnosed with a Staph. aureus intramammary infection as quarters not colonized on teat skin.
        Recombinant bovine interferon-τ enhances in vitro development of bovine embryos by upregulating expression of connexin 43 and E-cadherin. By Bao et al., page 6917. Recombinant bovine interferon-τ enhances in vitro development of bovine embryos by upregulating expression of connexin 43 and E-cadherin. Treating bovine embryo cultures or transfer medium with interferon-τ promotes the development of embryos and improves embryo transfer efficiency.
        Pathogen-specific incidence rate of clinical mastitis in Flemish dairy herds, severity, and association with herd hygiene. By Verbeke et al., page 6926. A 1-yr survey on 50 randomly selected Flemish dairy herds was conducted to study the clinical mastitis incidence rate, severity, and association with herd hygiene. The mean incidence rate was estimated at 7.4 quarter-cases per 10,000 cow-days at risk. Streptococcus uberis and Escherichia coli were most commonly isolated, and clinical signs were mostly mild. Overall and E. coli incidence rates of clinical mastitis were higher in dirty compared with clean herds.
        Rumination activity of dairy cows in the 24 hours before and after calving. By Pahl et al., page 6935. Monitoring of calving events in dairy cows is important to avoid complications and to ensure successful transition into lactation. Alterations in cow behavior might indicate upcoming parturitions and therefore offer an approach for sensor-based detection of calving events in growing dairy herds. In this study, short-term changes in rumination activity of dairy cows were analyzed. Although rumination intensity was unmodified around calving, the duration and frequency of rumination changed. Rumination time was decreased in the last 4 h prepartum and in the first 8 h postpartum and, among rumination characteristics, showed the most potential for monitoring of calving events.
        Effects of pathogen-specific clinical mastitis on probability of conception in Holstein dairy cows. By Hertl et al., page 6942. This study estimated effects of pathogen-specific clinical mastitis (CM) on probability of conception in 39,361 lactations from 5 New York State Holstein herds. Herd, parity, season of artificial insemination (AI), AI number (first, second, third, or fourth in a lactation), day of first AI, CM, and non-CM diseases were included in a generalized linear mixed model. The largest reductions in conception probability were associated with CM occurring shortly before or after AI. Escherichia coli and Klebsiella spp. had the greatest adverse effects on conception. These findings will help farmers better assess reproduction in their dairy cows for more effective cow management.
        Cardiac responses to palpation per rectum in lactating and nonlactating dairy cows. By Kovács et al., page 6955. Palpation per rectum is one of the most frequent methods used for pregnancy diagnosis or determining uterine diseases in dairy cattle. Heart rate and parasympathetic measures of heart rate variability were monitored in nonlactating and lactating dairy cows before and during transrectal examination and for 120 min thereafter. We found lower short-term stress responsiveness to the examination in lactating cows than in nonlactating animals, whereas the duration of the stress response was greater in lactating cows. The prolonged decline of parasympathetic tone in lactating animals suggests that palpation per rectum has a significant effect on dairy cattle welfare.
        Alfalfa baleage with increased concentration of nonstructural carbohydrates supplemented with a corn-based concentrate did not improve production and nitrogen utilization in earlylactation dairy cows. By Brito et al., page 6970. Feeding alfalfa baleage with an increased concentration of nonstructural carbohydrates supplemented with a corn-based concentrate did not improve milk production or nitrogen utilization in dairy cows during early lactation. Strategies to improve nitrogen utilization in dairy cows are required to reduce the environmental impact of dairy farming. It is hypothesized that diets containing alfalfa baleage with a high concentration of nonstructural carbohydrates would enhance milk yield and nitrogen utilization in early-lactation dairy cows. Overall, milk yield, nitrogen utilization, and bacterial protein synthesis were not improved, possibly as a result of similar intakes of dry matter and nonstructural carbohydrates across diets.
        Effect of feeding colostrum at different volumes, and subsequent number of transition milk feeds on the serum immunoglobulin G concentration and health status of dairy calves. By Conneely et al., page 6991. The health and wellbeing of calves depends on acquisition of adequate immunological protection from colostrum (the first milk of the cow) in the early hours of life. This study aimed to examine the effect of feeding colostrum as a percentage of calf body weight in conjunction with a varying number of transition milk feeds on the immune status and health of dairy calves. Ultimately, it is hoped that knowledge gained from this study may help reduce calf mortality rates.
        Reciprocal combinations of barley and corn grains in oil-supplemented diets: Feeding behavior and milk yield of lactating cows. By Kargar et al., page 7001. We investigated the effect of diets based on barley or corn, or their equal blend on feeding behavior and production performance of Holstein dairy cows. The substitution of barley grain with corn grain did not affect feeding patterns, including meal size and intermeal interval. Therefore, changing diet fermentability did not influence feed intake and milk yield under the current feeding situations.
        Exchanging physically effective neutral detergent fiber does not affect chewing activity and performance of late-lactation dairy cows fed corn and sugarcane silages. By Sá Neto et al., page 7012. Corn and sugarcane silages are attractive forage sources in tropical areas. The physical effectiveness of sugarcane fiber is greater than that of corn silage, increasing the potential for limiting feed intake via rumen filling. The objective of this study was to determine the effect of replacing the physically effective neutral detergent fiber (peNDF) of corn silage with sugarcane silage peNDF on dairy cow performance. Dry matter intake, milk yield, milk composition, ingestive behavior, and blood metabolites were similar across treatments. These results indicate that replacing corn silage peNDF with sugarcane silage peNDF does not affect dairy cow performance. Because more concentrates are required in a sugarcane silage-based diet than a corn silage-based diet, the economic implications of replacing corn silage with sugarcane silage require further consideration.
        Prevalence and potential influencing factors of non-nutritive oral behaviors of veal calves on commercial farms. By Leruste et al., page 7021. Veal calves raised under commercial conditions may express non-nutritive oral behaviors, some of which are considered abnormal. This study aimed to determine the prevalence of these behaviors in a large sample of veal calves and to identify the associated potential influencing factors at the farm level. The prevalence of nonnutritive oral behaviors varied between farms. Several factors were found to influence the prevalence of these behaviors with, for instance, a higher risk of tongue rolling when babyboxes were not used or a lower occurrence of manipulating substrates for calves fed maize silage compared with calves fed cereal grain, pellets, or muesli.
        Effect of unsaturated fatty acids and triglycerides from soybeans on milk fat synthesis and biohydrogenation intermediates in dairy cattle. By Boerman and Lock, page 7031. We investigated the effects of additional fat supplemented to the diet as either free fatty acid (FA) or esterified FA on production variables and the FA composition of milk. Supplemental fat reduced dry matter intake and increased milk yield, with no changes in milk fat or protein yield. Although we detected a reduction in the proportion of both de novo and 16-carbon milk FA, this decrease was compensated for by an increase in preformed (18-carbon) FA. Fat supplementation changed the FA profile of milk; however, we found no significant differences between free FA and esterified FA for common FA associated with milk fat depression.
        Milk fatty acids as possible biomarkers to early diagnose elevated concentrations of blood plasma nonesterified fatty acids in dairy cows. By Jorjong et al., page 7054. The milk fat C18:1 cis-9 was identified as a potential indicator for diagnosis and early warning of elevated concentrations of nonesterified fatty acids in blood plasma, which is an indicator of the animal's periparturient energy status. Monitoring this milk fat could allow for selective treatment of cows. However, based on the current dataset, the economic benefit of such a selective treatment was modest (maximum €2/cow per lactation), and analytical costs must be considered in this perspective. Consequently, the potential of milk fat C18:1 cis-9 as an early warning biomarker of detrimental blood plasma nonesterified fatty acids is of particular interest as routine spectrophotometric quantification is feasible.
        Effects of Cordyceps militaris on the growth of rumen microorganisms and in vitro rumen fermentation with respect to methane emissions. By Kim et al., page 7065. Methane produced as a result of digestible structural carbohydrates fermentation in the rumen by methanogens has received attention as a potential contributor to global warming. In this study, we showed that dried Cordyceps militaris mushroom grown on a floral medium has the ability to partly inhibit methane production in in vitro microbial fermentations. This compound stimulated mixed ruminal microorganism fermentation and decreased methane and hydrogen gas production.
        Meta-analysis of lactation performance in dairy cows receiving supplemental dietary methionine sources or postruminal infusion of methionine. By Zanton et al., page 7085. The objectives were to evaluate the productive response to methionine supplementation in lactating dairy cows and to define a relationship between metabolizable methionine (MPMet) intake and production. Increasing methionine supply by postruminal infusion or supplementing cows with rumen-protected MPMet resulted in increases in yields of both milk protein and fat. Based on regression analysis, the milk protein yield response to increased MPMet intake did not differ among sources, whereas milk fat yield response was greater for 2-hydroxy-4-methylthio butanoic acid than for other sources of MPMet.
        Use of a direct-fed microbial product as a supplement during the transition period in dairy cattle. By AlZahal et al., page 7102. This study focused on investigating the effects of feeding a direct-fed microbial (DFM) product (or probiotic) on feed intake, milk yield, milk components, and nutrient digestibility of dairy cows. The study also investigated the effect of DFM on disease incidence during the postcalving phase. We found that DFM had no effect on milk production, health parameters, or blood profiles but did increase total-tract digestibility of starch.
        Meta-analysis of relationships between enteric methane yield and milk fatty acid profile in dairy cattle. By van Lingen et al., page 7115. Methane emissions from cattle contribute to global warming. Milk fatty acid composition may provide an on-farm quantification tool for enteric methane emissions. The aim was to quantify relationships between enteric methane yield and milk fatty acid profile of dairy cattle and to develop empirical equations to predict methane emission based on milk fatty acid profile of cows fed a wide variety of diets. Various significant relationships were found. The potential for predicting methane yield based on milk fatty acid profile appeared to be moderate.
        Effect of feeding a negative dietary cation-anion difference diet for an extended time prepartum on postpartum serum and urine metabolites and performance. By Wu et al., page 7133. Historically, negative dietary cation-anion difference (DCAD) diets have been fed for 2 to 3 wk prepartum to reduce the incidence of clinical hypocalcemia. Limited information is available on the effect of feeding a negative DCAD for extended time prepartum. A trial was conducted to evaluate the effects of feeding a negative DCAD diet for 3, 4, or 6 wk prepartum. No differences were observed in serum or urine metabolite concentrations or intake and performance, suggesting that a negative DCAD diet can be fed for up to 42 d prepartum without affecting animal health or performance.
        Effects of feeding lutein on production performance, antioxidative status, and milk quality of high-yielding dairy cows. By Xu et al., page 7144. Sixty multiparous Holstein dairy cows were used and randomly allocated to 1 of 4 homogeneous treatments, with lutein preparation (extracted from marigold) added at different levels. Addition of lutein slowed the trend of declining milk yield and had a linear incremental effect on milk yield with an increase in lutein supplementation. The concentration of lutein in milk was also linearly increased by dietary lutein supplementation. In conclusion, addition of lutein to the diet improved both milk yield and quality.
        Evaluation of lower-starch diets for lactating Holstein dairy cows. By Dann et al., page 7151. Providing sufficient rumen-fermentable carbohydrates supports ruminal health and productivity. As the price of corn grain has increased, reducing dietary starch by reducing the inclusion of corn grain may be profitable for dairy farms. We found that reducing the dietary starch content from 24.6 to 17.7% of dry matter by replacement of corn grain with wheat middlings and beet pulp maintained similar chewing activity, ruminal function, and milk yield and composition. Dietary starch content can be reduced to approximately 18% of dry matter without sacrificing short-term lactational performance of high-producing dairy cows.
        Feeding lactating dairy cattle long hay separate from the total mixed ration can maintain dry matter intake during incidents of low rumen pH. By Kmicikewycz and Heinrichs, page 7175. Achieving maximum milk production in dairy cows increases the risk of subacute ruminal acidosis (SARA), which is an important nutritionally linked digestive disorder and an economic concern for producers. This study evaluated feeding high- or low-quality grass hay chopped and included in the total mixed ration (TMR) or long and separate from the TMR during a SARA challenge. Lactating cows were capable of sorting for chopped, low-quality hay particles in the TMR when induced with SARA. These results indicate lactating dairy cows consuming supplemental long hay separate from the TMR can maintain feed intake during incidents of and recovery from acidosis.
        Using the Small Ruminant Nutrition System to develop and evaluate an alternative approach to estimating the dry matter intake of goats when accounting for ruminal fiber stratification. By Regadas Filho et al., page 7185. We evaluated a modification to the Small Ruminant Nutrition System mechanistic model. Rather than using traditional, homogeneous modeling of the ruminal fiber pool, we considered a stratified, heterogeneous scenario, which yielded estimates of animal performance similar to those of the homogeneous scenario. We also added elements of a new approach for predicting the dry matter intake of lactating goats, which was reasonable and can be used in diet formulations. We expected that these modifications might be used to improve nutrition models and yield better estimates of an animal's performance.
        Effect of dairy slurry on silage fermentation characteristics and nutritive value of alfalfa. By Coblentz et al., page 7197. Dairy producers frequently ask questions about the risks associated with applying dairy manure slurry to growing alfalfa. To address these questions, dairy slurry was applied to alfalfa stubble or after 1 or 2 wk of regrowth, followed by an evaluation of subsequent silage fermentation and nutritive value. Based on pre- and postensiled clostridial counts, applications of slurry onto stubble are preferred (and less risky) compared with delayed applications on growing alfalfa. Based on visual observations, reduced crop damage from salt burn, wheel traffic, or smothering is likely when dairy slurry is applied to stubble rather than after regrowth has been initiated.
        Short communication: Effects of increasing protein and energy in the milk replacer with or without direct-fed microbial supplementation on growth and performance of preweaned Holstein calves. By Geiger et al., page 7212. Fortyfour Holstein calves were used at the Mississippi State University dairy to determine the effects of feeding increased crude protein and metabolizable energy in the milk replacer with or without a direct-fed microbial on calf performance and growth. Feeding an accelerated milk replacer compared with a standard milk replacer yielded significantly larger calves throughout the trial. Direct-fed microbial supplementation in the milk replacer did not benefit the calf.
        Short communication: Effect of dietary manipulation of crude protein content and nonfibrousto- fibrous carbohydrate ratio on energy balance in early-lactation dairy cows. By Whelan et al., page 7220. During early lactation, dairy cows face nutritional and metabolic challenges that may result in reduced health and reproductive performance. This experiment investigated the effects of 2 nutritional strategies on production, energy balance, and metabolic status in early-lactation dairy cows. Animals offered higher protein-fibrous carbohydrate type diets had higher milk yield and energy output compared with those offered lower protein-nonfibrous carbohydrate type diets. This resulted in a less favorable energy balance where the higher protein-fibrous carbohydrate diet was offered.
        Genetic analysis of atypical progesterone profiles in Holstein-Friesian cows from experimental research herds. By Nyman et al., page 7230. Suboptimal reproductive performance erodes profitability in dairy herds. An objective approach to classify estrus cycles is through analysis of milk progesterone. The aim of this study was to estimate genetic parameters for measures of normal estrus cycles, delayed cyclicity, prolonged luteal phases, and cessation of cyclicity in Holstein-Friesian cows. Delayed cyclicity and commencement of luteal activity were 3 to 4 times more heritable than traditional fertility measures and, as such, have the potential to improve the genetic evaluation and response in reproductive performance. Both traits were strongly genetically correlated with milk yield level in early lactation.
        Phosphorylation of αS1-casein is regulated by different genes. By Bijl et al., page 7240. Casein phosphorylation is one of the key factors responsible for the stabilization of calcium phosphate nanoclusters in casein micelles and for the internal structure of the casein micelles. This unique micellar structure allows milk to deliver large amounts of calcium and phosphate to the neonate, without enhanced risk of biocalcification in the mammary gland. The objective of this research was to determine the genetic background of αS1-casein phosphorylation with 8 and 9 phosphate groups. These results can help us understand the causes of variation in phosphorylation.
        Phenotypic factors affecting coagulation properties of milk from Sarda ewes. By Pazzola et al., page 7247. Milk coagulation properties obtained at the laboratory level are commonly used to predict technological characteristics for cheese-making in the dairy industry but they are not well known in small ruminants. In this study, we measured milk coagulation properties in 1,121 ewes from 23 flocks of one of the most important European dairy sheep breeds, the Sarda. Compared with bovine milk, sheep milk is characterized by earlier coagulation and higher curd firmness; we also showed that some of the assumptions and interpretations developed for cattle cannot be applied to sheep.
        Genome-wide association study using high-density single nucleotide polymorphism arrays and whole-genome sequences for clinical mastitis traits in dairy cattle. By Sahana et al., page 7258. This study attempted to identify major genes affecting mastitis in dairy cattle. Six chromosomal regions, selected from an association study using a high-density single nucleotide polymorphism array, were further associated with sequence-level variants. We used 4,992 progeny-tested Holstein bulls as a discovery population for identifying quantitative trait loci (QTL), and we used 4,442 Nordic Red and 1,126 Jersey bulls for confirmation populations. The QTL on chromosomes 6, 13, and 19 were confirmed in Nordic Red cattle, and QTL on chromosomes 16 and 20 were confirmed in Jersey cattle. Whole-genome sequence data mapped the QTL more precisely, and a number of candidate genes were identified. It was not possible to determine causal genes or polymorphisms primarily because of high linkage disequilibrium in the targeted regions.
        A quantitative trait locus on Bos taurus autosome 17 explains a large proportion of the genetic variation in de novo synthesized milk fatty acids. By Duchemin et al., page 7276. The finemapping of Bos taurus autosome 17 revealed a genomic region associated with several de novo synthesized milk fatty acids. This region explains almost 10% of the genetic variation in C6:0 content (% wt/wt) of summer milk samples. After testing for differences between predicted haplotype effects, 1 quantitative trait locus was shown to be present in this region. This locus might be involved in the elongation or early termination of de novo synthesized fatty acids. The strongest association in this region was found close to the progesterone receptor membrane component 2 (PGRMC2) gene.
        Genetic analysis of milk β-hydroxybutyrate and its association with fat-to-protein ratio, body condition score, clinical ketosis, and displaced abomasum in early first lactation of Canadian Holsteins. By Koeck et al., page 7286. Hyperketonemia or ketosis is one of the most frequent diseases in dairy cattle. As ketosis is not widely recorded, the level of milk β-hydroxybutyrate (BHBA) could be used as an indicator trait. Heritability estimates for milk BHBA in Canadian Holstein cows were between 0.14 and 0.29. Higher milk BHBA in early lactation was genetically associated with a higher fat-to-protein ratio, a lower body condition score, and a higher frequency of clinical ketosis. Milk BHBA can be routinely analyzed in milk samples at test-days, and, therefore, provides a practical alternative for breeding cows with a lower susceptibility to hyperketonemia.
        Technical note: Advantages and limitations of authenticating Palmera goat dairy products by pyrosequencing the melanocortin 1 receptor (MC1R) gene. By Badaoui et al., page 7293. Molecular techniques can be used to authenticate the origin of dairy products by using genetic markers with a breed-specific pattern of segregation. We used this principle to develop a minisequencing quantitative method to genotype a mutation at the caprine melanocortin 1 receptor (MC1R) gene with highly divergent allelic frequencies in Palmera compared with Majorera and Tinerfeña goat breeds. Testing of this technique in genomic DNA extracted from cheese samples demonstrated that it generates a very specific DNA profile for the Palmera breed, allowing detection of fraud in which Palmero cheese is manufactured with milk from other breeds (mainly Majorera).
        Application of liquid semen technology improves conception rate of sex-sorted semen in lactating dairy cows. By Xu, page 7298. Liquid sexed semen at half the dose rate of frozen sexed semen was able to achieve, in lactating dairy cows, a reproductive performance that was 94% of that of conventional semen. Successful implementation of liquid sexed semen can increase both efficiency (twice as many semen doses per unit time of sorting) and conception rate, thus making sexed semen suitable for seasonal dairy production systems.