Interpretive summaries, September 2010

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Invited review: Annatto usage and bleaching in dairy foods. By Kang et al., page 3891. Annatto is a yellow-orange colorant extracted from the fruit of a tree that grows in South and Central America. Most commonly, annatto is used to produce yellow Cheddar cheese. The colorant is not fully retained in the cheese and a percentage remains in the whey, which is undesirable. It is necessary to remove the residual annatto colorant in the whey because it can change the attributes of the final food product. This review discusses the history and usage of annatto along with the advantages, disadvantages, regulations, and optimal usage conditions of hydrogen peroxide and benzoyl peroxide.

Effects of seasonal changes in feeding management under part-time grazing on the evolution of the composition and coagulation properties of raw milk from ewes. By Abilleira et al., page 3902. Composition and technological properties of ewe raw milk produced for cheesemaking were studied in commercial flocks throughout the milking season. During that period the feeding of the flocks changed from an indoor diet, which consisted of concentrate and forages, to an outdoor diet based mainly on grazing. More consistent curds were obtained at the end of the milking season under outdoor grazing system, and this greater consistency was related to the higher nutrient content of the milk. This study is a good example of how milk of high technological quality can be obtained maximizing the use of natural resources.

A methodology for monitoring globular milk protein changes induced by ultrafiltration: A dual structural and functional approach. By Van Audenhaege et al., page 3910. Protein fractionation using membrane separation is an important value-adding breakthrough for the valorization of milk proteins as functional ingredients. However, it is still necessary to determine whether such operations guarantee an excellent structure and functionality for the obtained protein fractions. In this study, we proposed a pertinent analytical package to examine the effect of filtration on globular milk protein characteristics in both dead-end and crossflow modes.

Effect of bovine lactoferricin on DNA methyltransferase 1 levels in Jurkat T-leukemia cells. By Zhang and Liu, page 3925. Lactoferrin was first fractionated as an unknown “red fraction” from cow's milk in 1939. In 1960, the red protein from both human and bovine milk was defined as a transferrin-like glycoprotein. Lactoferricin B (LFcin B), which is released by gastric pepsin cleavage of bovine lactoferrin, consists of a positively charged looped peptide containing residues 17 to 41. Lactoferricin B exhibits a range of biological activities, including cytotoxic activity against various microorganisms and cancer cells. Our results demonstrated that Lfcin B reduced the expression of DNA methyltransferase 1 and the stability of DNA methyltransferase 1 mRNA in Jurkat T-leukemia cells. The information may be helpful to clarify more about the activity of Lfcin B

Neutral and acidic oligosaccharides in Holstein-Friesian colostrum during the first 3 days of lactation measured by high-performance liquid chromatography on a microfluidic chip and time-of-flight mass spectrometry. By Barile et al., page 3940. In the present work we measured free milk oligosaccharides (OS) in the colostrum of 7 Holstein- Friesian cows during the first 3 days of lactation by high performance liquid chromatography-chip/time-of-flight mass spectrometry to determine the biological variation of OS in early lactation. The high sensitivity and resolution of the analytical technique made it possible to monitor all OS species, providing a comprehensive and quantitative analysis of OS variations during colostrum production. This study confirmed that although sialyllactose is the major OS in bovine colostrum, several neutral OS species were also present in significant abundance even on the third day of lactation.

Physicochemical analysis of full-fat, reduced-fat, and low-fat artisan-style goat cheese. By Sánchez- Macías et al., page 3950. Artisan cheese-makers need to diversify their products to compete with the industrial low-fat cheese market. We report the effects of milk fat reduction on the physicochemical properties of cheese made from raw goat milk using artisan methods. This study indicates that fat reduction decreases cheese palatability and suggests alternative procedures for the production of healthy raw goat milk cheese to increase desirability for consumers.

Short communication: Correlation of on-site inspection and laboratory milk testing results for Wisconsin grade A dairy farms in 2007 to 2008. By Ingham et al., page 3957. To evaluate milk safety and quality, US grade A dairy farms are subject to mandatory farm inspections and milk testing in laboratories for somatic cell count, standard plate count, and drug residues. To begin determining whether farm inspection procedures should be changed, we evaluated the correlation of farm inspection results and laboratory test results for Wisconsin grade A dairy farms in 2007 and 2008. Farms with unacceptable laboratory results were more likely to fail farm inspection, but correlations were weak, probably because farm inspection and laboratory testing are often done at different times. The data support reevaluation of farm inspection procedures.

Short communication: Rapid antibiotic screening tests detect antibiotic residues in powdered milk products. By Kneebone et al., page 3961. Monitoring milk products for the presence of antibiotic residues is of particular importance in the dairy industry. The objective of this study was to investigate the utility of IDEXX Snap rapid antibiotic screening tests (IDEXX Laboratories Inc., Westbrook, ME) as tools for detecting antibiotic residues in commercially available powdered milk products. Our results showed that both β-lactam and Tetra IDEXX Snap tests effectively detect antibiotic residues in reconstituted commercially available powdered milk samples.

Short communication: Antimicrobial effect of lactoferrin and its amidated and pepsin-digested derivatives against Salmonella Enteritidis and Pseudomonas fluorescens. By Del Olmo et al., page 3965. The antimicrobial effect of 0.25 to 20mg/mL of concentrations of bovine lactoferrin (LF) and its amidated and pepsin-digested derivatives against 3 Salmonella Enteritidis strains and 3 Pseudomonas fluorescens strains was investigated. Bovine LF showed its maximum antimicrobial effect against Salmonella and Pseudomonas at 10mg/mL, amidated LF at 0.25mg/mL against Salmonella and at 1mg/mL against Pseudomonas, and pepsin-digested LF at 1mg/mL against Salmonella and at 20mg/mL against Pseudomonas. A pronounced effect was recorded for a low concentration (1mg/mL) of pepsin-digested LF, which is naturally formed in the gastrointestinal tract, on Salmonella and Pseudomonas strains.

Behavior during transition differs for cows diagnosed with claw horn lesions in mid lactation. By Proudfoot et al., page 3970. This study investigated whether cows diagnosed with claw horn lesions in mid lactation behave differently during the calving period when lesions are thought to first develop. Feeding and standing behavior were retrospectively compared from 2 wk before to 3 wk after calving for 13 cows diagnosed with lesions in mid lactation and 13 cows without lesions. Cows with lesions stood longer (particularly with their front feet in the stall) and ate faster 2 wk before calving and consumed more feed during the 24 h and the week after calving compared with cows without lesions.

Risk factors for skin lesions on the necks of Norwegian dairy cows. By Kielland et al., page 3979. The feeding area is an essential part of free stall housing, and skin lesions on the necks of dairy cattle may be indicative of inappropriate design within that area. A cross-sectional study conducted in 2006 and 2007, which including 2,335 cows in 232 herds, collected detailed information about feed barrier and feeding management. Post-and-rail design feed barriers were found to be strongly associated with neck lesions on cows. Neck lesions were found to be associated with details in feed barrier design, feeding regimen, and cow shoulder height and attitudes of farmers toward animals.

Effects of in vitro insulin and 2,4-thiazolidinedione on the function of neutrophils harvested from blood of cows in different physiological states. By Revelo and Waldron, page 3990. Neutrophils are immune cells that have an essential role in the protection against invading pathogens during infections. We purified and treated neutrophils from prepartum, postpartum, and midlactation dairy cows with insulin alone or in combination with 2,4-thiazolidinedione (TZD), a compound that has insulin-like effects. Neutrophils from postpartum cows had lower production of reactive oxygen species (ROS) compared with midlactation and prepartum cows, suggesting that cows around parturition have altered immune function. Insulin did not have any effects on neutrophil function, but TZD dramatically reduced a proxy of total ROS production without altering the capacity of the cells to eliminate Staphylococcus aureus. These findings suggest that TZD could minimize tissue damage caused by excess ROS production during an infection without compromising the neutrophil antimicrobial ability.

Effects of resynchronization programs on pregnancy per artificial insemination, progesterone, and pregnancy-associated glycoproteins in plasma of lactating dairy cows. By Thompson et al., page 4006. Resynchronization protocols create the opportunity for improvement in reproductive performance of dairy cows. Measurement of plasma pregnancy-associated glycoproteins is used as a method of pregnancy diagnosis. An experiment was conducted to determine reproductive responses of lactating dairy cows receiving an intravaginal progesterone insert 18 to 25 d after artificial insemination (AI). Pregnancyassociated glycoproteins plasma concentrations were measured from d 18 to 60 after AI. No differences in pregnancy per AI or pregnancy loss were observed between treatments. Measurement of plasma pregnancyassociated glycoproteins concentrations was a reliable diagnosis of pregnancy and an indicator of fetal and embryo survival.

Relationship between udder health and hygiene on farms with an automatic milking system. By Dohmen et al., page 4019. Udder health is at risk on farms with an automatic milking system. Poor hygiene is an important risk factor for reduced udder health. In this study the hygiene-specific risk factors for reduced udder health on farms with an automatic milking system were identified at the farm level as well as at the cow level. At both levels, hygiene of the cow is related to somatic cell count. On farms with an automatic milking system, cow hygiene is important for udder health.

Bioeconomic modeling of lactational antimicrobial treatment of new bovine subclinical intramammary infections caused by contagious pathogens. By van den Borne et al., page 4034. The direct and indirect epidemiologic and economic effects of lactational treatment of contagious bovine subclinical mastitis pathogens were investigated using a bioeconomic simulation model. Lactational intervention resulted in fewer clinical flare ups, less transmission of pathogens within dairy herds, and lower associated costs. Lactational treatment of contagious subclinical mastitis seems economically beneficial in dairy herds that implement management measures to decrease the transmission of mastitis pathogens within the herd. Detection of new subclinical mastitis cases needs to be improved to be able to effectively treat subclinical mastitis during lactation.

Association between milk yield and serial locomotion score assessments in UK dairy cows. By Archer et al., page 4045. Lameness is a painful disease of dairy cows that has been associated with decreased milk production. Consumer awareness of welfare issues is increasing and assurance schemes require that farmers have lameness control plans and actively monitor them. The identification of lame cows is subjective, and routine grading of locomotion using a scoring system has been recommended. Quantifying the association between locomotion score and milk yield is expected to help develop cost-effective lameness control plans and enhance the reputation of the dairy industry with consumers.

Effects of 6 times daily milking during early versus full lactation of Holstein cows on milk production and blood metabolites. By Eslamizad et al., page 4054. We compared milking 6 or 3 times daily for the entire lactation to 6 times daily milking for the first 90 d in milk followed by 3 times daily milking. Our results indicated that increasing milking frequency increases milk production, but no difference was found between milking 6 times daily for full and early lactation periods.

The effects of milk removal or four-times-daily milking on mammary expression of genes involved in the insulin-like growth factor-I axis. By Wall and McFadden, page 4062. Relative to twicedaily milking, four-times daily milking during the first 3 wk of lactation can increase milk production for the remainder of lactation; however, the mechanisms underlying this response are unknown. In this experiment, we used a half-udder design to characterize both the acute mammary response to milking and the sustained response to four-times daily milking treatment. Our results show that several genes involved in the insulin-like growth factor-I axis are responsive to milk removal or to increased milking frequency.

The effect of claw horn disruption lesions and body condition score at dry-off on survivability, reproductive performance, and milk production in the subsequent lactation. By Machado et al., page 4071. Lameness and poor body condition in dairy cattle result in animal welfare concerns as well as economic losses on dairy farms. This study evaluated the effects of claw horn disruption lesions (sole ulcers and white line disease) and body condition score at dryoff on survivability, milk production, and reproductive performance during the subsequent lactation. Cows diagnosed with claw horn disruption lesions at dry-off were more likely to be culled and less likely to conceive than cows without claw horn disruption lesions. Cows underconditioned at dry-off were more likely to be culled and produce less milk and were less likely to conceive than cows with adequate body condition

Effects of 2.1 and 3.5×10⁶ sex-sorted sperm dosages on conception rates of Holstein cows and heifers. By DeJarnette et al., page 4079. Holstein heifers and cows were inseminated with 2.1 or 3.5×10⁶ sex-sorted sperm or 15×10⁶ conventionally processed sperm from 7 Holstein sires. Conception rates of the 2.1 and 3.5×10⁶ sex-sorted sperm dosage were comparable with each other but were lower than conventional insemination within and across almost all sires in both cows and heifers. When compared in an unbiased manner, sexed semen (both dosages) achieved conception rates that were approximately 75% of those achieved with conventional semen at conventional sperm dosages.

Resynchronization strategies to improve fertility in lactating dairy cows utilizing a presynchronization injection of GnRH or supplemental progesterone: I. Pregnancy rates and ovarian responses. By Dewey et al., page 4086. Three resynchronization protocols were evaluated: 1) at nonpregnancy diagnosis (d 0), cows were submitted to a timed artificial insemination (AI) protocol [d 0: gonadotropinreleasing hormone (GnRH); d 7: prostaglandin F_2α (PGF_2α); d 10: GnRH + AI; control); 2) cows in the GnRH-GnRH-PGF_2α-GnRH treatment received an additional GnRH 7 d before pregnancy diagnosis; and 3) cows received a controlled internal drug release (CIDR) insert containing progesterone from d 0 to 7. Cows in GnRH-GnRH-PGF_2α-GnRH treatment had more corpora lutea on d 0 and 7 and were more likely to ovulate to GnRH treatment on d 0 than cows in either the control or CIDR groups. Presynchronization with GnRH and treatment with CIDR increased pregnancies per AI.

Evaluation of a biological risk management tool on large western United States dairies. By Moore et al., page 4096. A risk assessment tool to identify potential disease transmission risks was evaluated, refined, and tested on large western United States dairies. Questions were reworded and the new assessment tool is provided. Forty dairy farmers evaluated their herds’ infectious disease introduction risks. Some of the more common vulnerabilities included introduction of new animals onto the farm, lack of isolation facilities for new or returning animals, and lack of visitor protocols or restrictions.

Cefoperazone sodium preparation behavior after intramammary administration in healthy and infected cows. By Cagnardi et al., page 4105. The pharmacokinetic profile of cefoperazone (CFP) after single intramammary administration in healthy and subclinical infected Staphylococcus aureus cows and the minimum inhibitory concentration (MIC) of S. aureus field strains were carried out together with the systemic drug absorption in healthy and infected animals. The systemic drug absorption was negligible in healthy animals, whereas it was higher in infected animals. The MIC90 value for CFP in S. aureus field strains (n=24) was 0.64μg/mL. The results showed a longer persistence of CFP in infected quarters than in healthy ones.

Physiological calf responses to increased chromium supply in summer. By Yari et al., page 4111. Increased chromium supply from d 4 of age through weaning and continuing until 3 wk postweaning improved postweaning insulin metabolism, altered preweaning blood glucose and cortisol, decreased postweaning dry matter intake, reduced respiration rate at wk 5, and did not affect calf growth. Findings suggest beneficial postweaning effects of chromium on insulin metabolism in young Holstein calves under high ambient temperatures.

Effect of saturated fatty acid supplementation on production and metabolism indices in heat-stressed mid-lactation dairy cows. By Wang et al., page 4121. Heat stress is a significant financial burden throughout the world. The present study determined the effects of supplemental saturated fatty acids on milk production and metabolic parameters in mid-lactation dairy cows already experiencing heat stress. Feeding supplemental saturated fatty acids decreased afternoon rectal temperatures and increased both milk yield and milk fat yield while decreasing serum nonesterified fatty acid concentration.

Predicting energy × protein interaction on milk yield and milk composition in dairy cows. By Brun-Lafleur et al., page 4128. Energy and protein supplies are two of the main factors that affect milk production. Separately, they both increase milk yield curvilinearly, but their joint effect is not well researched. This study showed an interaction between energy and protein, consistent with the concept of the more limiting factor. The results enabled us to build equations for the response of milk yield and composition to simultaneous variations in energy and protein and to highlight the role of parity and potential production of the cows in that response.

Ruminal degradability and intestinal digestibility of protein and amino acids in soybean and corn distillers grains products. By Mjoun et al., page 4144. Crude protein (CP) and amino acid (AA) degradation from the rumen and their digestibility in the small intestine were measured in soybean and distillers grains (DG) products using in situ and in vitro techniques. Soybean meal and modified wet distillers grains with solubles were more extensively degraded in the rumen than dried DG from different processing methods. Intestinal digestibility of CP and most AA in DG products exceeded 92.0% and was slightly lower than for soybean products. More protein and AA were available for absorption in dried DG, expeller soybean meal, and extruded soybeans compared with soybean meal and modified wet distillers grains with solubles.

Effect of multiple intravenous injections of butaphosphan and cyanocobalamin on the metabolism of periparturient dairy cows. By Fürll et al., page 4155. A transient and acute state of negative energy balance and inadequate feed intake occurs in dairy cattle around the time of calving. The major findings of this study were that multiple intravenous injections of cyanocobalamin and butaphosphan before calving produced a beneficial effect on the metabolism of dairy cows. Our results are consistent with the hypothesis that high producing dairy cows in early lactation may have a relative or actual deficiency of cyanocobalamin.

Morphology, proliferation, and ribonucleic acid and fractional protein syntheses in the small intestinal mucosa of young goats fed soy protein-based diets with or without amino acid supplementation. By Schönhusen et al., page 4165. Dietary protein sources affect development of the small intestinal mucosa in preruminant goats. Morphological changes in the jejunal mucosa induced by partial replacement of milk protein by soy protein isolate are accompanied by a trend for increased fractional protein synthesis rate in jejunum and a tendency for an increased leucine oxidation. Feeding soy protein isolate supplemented with free indispensable amino acids does not ameliorate soy protein effects on intestinal mucosa growth in a significant manner, but counteracts some soy feeding effects on protein utilization.

Particle size distribution and chemical compostion of total mixed rations for dairy cattle: Water addition and feed sampling effects. By Arzola-Álvarez et al., page 4180. The effects of water addition to diets and sample collection location on the particle size distribution and chemical composition of total mixed rations were determined. Particle size distributions differed with month, sampling location within the feed bunk, and water content. Chemical composition also varied with month of sampling but was within recommended ranges for high-yielding dairy cows. Analyses of particle size distributions of total mixed rations are useful for proper feed bunk management and formulation of diets that maintain rumen function and maximize milk production and quality. Water addition may help reduce dust associated with feeding total mixed rations.

Supplementation of the diet of dairy cows with trehalose results in milk with low lipid peroxide and high antioxidant content. By Aoki et al., page 4189. The objective of this study was to investigate the effect of dietary supplementation with the disaccharides trehalose and cellobiose on antioxidant activity in rumen fluid, blood, and milk of dairy cows. Dietary supplementation with trehalose brought about an improvement of the oxidative status of milk and blood compared with controls. The findings suggest that trehalose might be a useful supplement for reducing oxidative stress, improving the quality of milk for human consumption, and possibly impairing the processes that give rise to lipid oxidation odor in dairy cow milk.

Effects of dietary cation-anion difference on ruminal metabolism and blood acid-base regulation in dairy cows receiving 2 contrasting levels of concentrate in diets. By Apper-Bossard et al., page 4196. High-producing dairy cows are commonly fed diets rich in degraded starch, which can cause subacidosis and reduce dry matter intake and animal performance, implying economic losses. Increasing the dietary cation-anion difference limits the decrease of dry matter intake and milk yield. This study established that the mechanisms involved both an enhancement of animal acid-base status and a local rumen buffering effect. Renal mineral metabolism and finally urine excretion of proton and mineral are the principal ways to maintain blood homeostasis in cows faced with a massive acid input from the diet.

Effect of dietary concentrate on rumen fermentation, digestibility, and nitrogen losses in dairy cows. By Agle et al., page 4211. The main objective of this experiment was to investigate the effect of level of dietary concentrate on nitrogen losses in lactating dairy cows and ammonia emission from manure. Increased concentrate proportion in the diet resulted in more efficient utilization of ruminal ammonia for milk protein synthesis, but this did not correspond to reduced urinary nitrogen losses. Increasing dietary concentrate was not a successful strategy for mitigating either enteric methane production or ammonia emission from manure.

Effects of particle size and dry matter content of a total mixed ration on intraruminal equilibration and net portal flux of volatile fatty acids in lactating dairy cows. By Storm and Kristensen, page 4223. The effects of changes in consistency of the medial ruminal mat on intraruminal volatile fatty acid (VFA) equilibration and net portal flux of VFA was investigated by feeding 2 levels of forage particle size and 2 levels of dry matter content in a total mixed ration. The total mixed ration dry matter content did not affect any measured variable. Decreased forage particle size decreased the size of the medial ruminal mat and the medial pool of total VFA, acetate, propionate, butyrate, isobutyrate, and isovalerate without affecting the net portal flux of any VFA. It is concluded that the medial ruminal mat pool of VFA was proportional to the size of the mat and the only detected effects of decreasing forage particle size were decreasing the mat size and increasing turnover of the mat pool of VFA.

Effects of feeding organic trace minerals on milk production and reproductive performance in lactating dairy cows: A meta-analysis. By Rabiee et al., page 4239. Twenty studies on effects of organic trace minerals (Availa-4 and 4-Plex; Zinpro Corp., Eden Prairie, MN) in lactating dairy cows were considered in this meta-analysis. These treatments increased milk production by 0.93kg, milk fat yield by 0.04kg, and milk protein yield by 0.03kg/cow per day. Supplementation with the organic trace minerals reduced days open by 13.5 days and number of services per conception by 0.27. The risk of pregnancy on day 150 of lactation tended to be greater in cows fed organic trace minerals. Treatment had no effect on calving to first service interval or 21-d pregnancy rate.

Effect of method of conservation of timothy on endogenous nitrogen flows in lactating dairy cows. By Ouellet et al., page 4252. The effect of method of forage conservation on endogenous N flow in the gastrointestinal tract of dairy cows was studied. Forage timothy was conserved as hay or as silage, with the latter either restrictively (formic acid) or extensively (lactic acid bacterial inoculant) fermented. Duodenal flow of free endogenous N and total endogenous N was higher for hay compared with silages. Fecal endogenous N flows were not affected by treatments. Endogenous N averaged 25% of total duodenal N and 10% of fecal N. Estimation of net N supply and requirements of the dairy cow should account for endogenous N flows and losses.

The effects of feeding medium-chain triglycerides on the growth, insulin responsiveness and body composition of Holstein calves from birth to 85kg of body weight. By Mills et al., page 4262. Milk replacer formulation traditionally relies on the use of long-chain saturated fatty acids from lard and tallow. Bovine milk comprises more than 400 fatty acids, some of which have specific roles in metabolism and antimicrobial activity. The results of this study demonstrate that the energy demand of the calf to maintain body temperature resulted in increased oxidation of intake energy; thus, overall body composition differences could not be detected.

The effect of group composition and age on social behavior and competition in groups of weaned dairy calves. By Færevik et al., page 4274. When calves are housed in groups, competition for attractive resources like food and resting places may influence individual animal welfare and performance. Knowledge about how housing systems and management, for instance, group composition, influence the level of competition is therefore important. The results from this study show that newly weaned calves are subject to more competition in age-heterogeneous groups than in age-homogenous groups and that young calves in age-heterogeneous groups are displaced from the feed manger by older calves. The results indicate that keeping calves in groups with large age differences may have a negative influence on performance of young calves.

Effects of feeding polyphenols from pomegranate extract on health, growth, nutrient digestion, and immunocompetence of calves. By Oliveira et al., page 4280. Feed additives that enhance calf health and performance are of major interest to food animal production. Pomegranate extract contains polyphenols with marked cellular effects both in vitro and in vivo. Feeding pomegranate extract suppressed weight gain after 30 d of age, possibly because of a reduction in grain intake and protein digestibility. Measures of health and neutrophil activity were not altered by feeding pomegranate extract, but linear increases in antibody response to immunization and in vitro production of lymphocyte-derived cytokines were observed. Results indicate that immune response was altered by feeding polyphenols despite reduction in grain intake and weight gain.

Short communication: Effects of dietary nonstructural carbohydrates pre- and postpartum on reproduction of grazing dairy cows. By Burke et al., page 4292. A postpartum diet high in nonstructural carbohydrates, but comparatively isoenergetic to a low nonstructural carbohydrate diet, reduced the postpartum anovulatory interval by 8 d in grazing dairy cows. The findings demonstrate potential to improve reproductive performance in grazing cattle through manipulation of diet composition in early postpartum.

Short communication: Effects of dietary fat supplements and forage:concentrate ratio on feed intake, feeding, and chewing behavior of Holstein dairy cows. By Kargar et al., page 4297. The effects of dietary fat source and forage to concentrate ratio (F:C) on dry matter intake and feeding behavior of Holstein dairy cows were investigated. Cows were fed 1) a control diet without dietary fat, 2) 2% hydrogenated palm oil at low F:C (34:66), 3) 2% yellow grease at low F:C (34:66), or 4) 2% yellow grease at high F:C (45:55) diet. Feed intake, meal pattern, and chewing activity were not affected by fat supplementation. Results indicate that hydrogenated palm oil and yellow grease can be fed to dairy cows without adverse effects on feed intake and chewing activity.

Increasing milk solids production across lactation through genetic selection and intensive pasture-based feed system. By Coleman et al., page 4302. Three genotypes of Holstein-Friesian dairy cattle were established based on their origin and overall genetic merit. Genetic merit was estimated using the Irish total merit index (EBI). High EBI genotypes that were within the top 10% of the population ranked on EBI produced greater volumes of milk solids and maintained superior body condition score during lactation when compared with the national average dairy cow. In addition, when concentrate supplementation was used to facilitate increased stocking rates, increase levels of herbage utilization were maintained and smaller substitution rates of herbage for concentrate were observed.

Dry matter intake and feed efficiency profiles of 3 genotypes of Holstein-Friesian within pasturebased systems of milk production. By Coleman et al., page 4318. Three genotypes of Holstein-Friesian dairy cattle were established based on their origin and overall genetic merit. Total dry matter intake did not differ between genotypes across lactation. The relative superiority of the different genotypes differed with the definition of feed efficiency. The results also suggest that traditional feed efficiency definitions such as feed conversion efficiency and residual feed intake may not be ideal measures of feed efficiency but that a newly defined trait, residual solids production, may have a role to play in future selection programs.

Association between the polymorphism of the goat stearoyl-CoA desaturase 1 (SCD1) gene and milk fatty acid composition in Murciano-Granadina goats. By Zidi et al., page 4332. Sequence analysis of the goat stearoyl-CoA desaturase 1 (SCD1) gene, which catalyzes the synthesis of monounsaturated and conjugated linoleic fatty acids (CLA) in the mammary gland, allowed us to identify 3 polymorphisms located in the coding region (c.732C > T) and in the 3′ untranslated region (c.*1902_1904delTGT and c.*3504G > A). Performance of an association analysis with dairy traits revealed that the two 3′ untranslated region polymorphisms are suggestively associated with milk polyunsaturated fatty acid and CLA contents. This finding is relevant from a human health perspective because unsaturated fatty acids and CLA have been shown to have beneficial effects on cancer and atherosclerotic diseases.

Caprine CSN1S1 haplotype effect on gene expression and milk composition measured by Fourier transform infrared spectroscopy. By Berget et al., page 4340. The Norwegian dairy goat population has a high frequency of a casein haplotype with large negative effects on protein and fat content of the milk. In this study we show that goats being homozygous for this haplotype are characterized by very low levels of α_S1-casein mRNA in the mammary gland. Moreover, Fourier transform infrared spectra of milk samples could potentially identify animals with such genotypes. We therefore suggest to extend the use of Fourier transform infrared spectra in goat milk quality control and to focus not only on protein content but also on protein composition.

Comparison of different models for genetic analysis of clinical mastitis in Austrian Fleckvieh dual-purpose cows. By Koeck et al., page 4351. This is the first genetic analysis of clinical mastitis for Fleckvieh dual-purpose cows based on data from the Austrian health recording system. Heritabilities of mastitis from probit and logit threshold models were 0.06 and 0.08, respectively, whereas heritabilities for linear sire and linear animal models were lower (0.02). Genetic evaluation of sires obtained with linear and threshold models were highly correlated (rank correlation >0.96). Overall, linear models were found to be robust toward departures from normality and performed equally well as threshold models.

Analysis of the relationship between workability traits and functional longevity in Canadian dairy breeds. By Sewalem et al., page 4359. The aim of this study was to assess the effect of milking speed and milking temperament on functional longevity of Canadian dairy cows. A statistically significant association was found between workability traits and functional longevity. Bad-tempered cows (very nervous) were 26, 23, and 46% more likely to be culled compared with very calm cows in Holstein, Ayrshire, and Jersey breeds, respectively. Similarly, very slow milkers were 36, 33, and 28% more likely to be culled compared with average milkers. Moreover, very fast milkers were also at higher risk of being culled compared with the average milkers (11, 13, and 15% for Holstein, Ayrshire, and Jersey breeds, respectively).

Impact of genetic progress on the profits of dairy farmers. By Roibas and Alvarez, page 4366. This study used a sample of dairy farms in northern Spain to evaluate the contribution of genetic progress to dairy farmers’ profits. A novel data set of commercial dairy farms including genetic evaluation records of cows and management data was used. Results obtained show that the average genetic progress during the sampling period is equivalent to a 5% increase in income from milk sales. Management plays an important role in exploiting the potential of genetics. Optimally managed farms reached a return on genetics that was 22% larger than the return achieved by the average managed farms.

Energy balance in first-lactation Holstein, Jersey, and reciprocal F₁ crossbred cows in a planned crossbreeding experiment. By Olson et al., page 4374. Characteristics of energy balance in Holstein, Jersey, and reciprocal crossbred, first-lactation cows were assessed. No genetic group differences were found for weeks to positive energy balance, weeks to cumulative positive energy balance, or total energy balance. Purebred Holsteins allocated more energy to maintenance than cows that were Jersey sired by Holstein dams and less energy to production than purebred Jerseys. Holsteins and Holsteins sired by Jersey dams allocated more energy to growth than Jerseys. No differences were found between reciprocal crossbred cows.

Short communication: Genetic variation of saturated fatty acids in Holsteins in the Walloon region of Belgium. By Arnould et al., page 4391. The genetic parameters of daily milk production traits are commonly estimated based on random regression test-day models using Legendre polynomials. The description of genetic variation of fatty acids in milk might require different models. This study compared a Legendre polynomials model with models fitting linear splines and reduced rank linear splines. Rank reduction was used to reduce a model with large number of splines to a model having identical number of parameters like using Legendre polynomials. Results indicated that the reduced spline model performed similarly to the Legendre polynomials model.

Short communication: Genetic relationship between calving traits and body condition score before and after calving in Canadian Ayrshire second-parity cows. By Bastin et al., page 4398. Because body condition of dairy cows before calving may have an effect on subsequent calving performance, the objective of this study was to investigate the genetic relationship across time of calving traits (calving ease and calf survival) with body condition score recorded from 100 d before calving to 335 d after calving. Results indicated that the genetic correlation between body condition score 10 d before calving and maternal calving ease was 0.32 and emphasized the relationship between fat cows before calving with dystocia. Genetic correlation estimates between body condition and calf survival were moderate to high and favorable.

Economic comparison of natural service and timed artificial insemination breeding programs in dairy cattle. By Lima et al., page 4404. Poor estrus detection is a major reproductive problem for lactating dairy cows. Timed artificial insemination and the use of natural service bulls are 2 breeding programs that do not require estrus detection and are therefore widely used in the United States. The present study compared the economics of these 2 breeding programs that were used on the same dairy farm. Timed artificial insemination was less expensive than the use of bulls in the field study. Marginal feed cost and semen price had major effects on the economic results.

An advisory tool to improve management practices affecting calf and heifer welfare on dairy farms. By Vasseur et al., page 4414. An advisory tool to identify the critical points at which management affects the welfare of calves and heifers was developed and tested on 28 farms. Within a 3-h visit the tool allowed us to cover all aspects targeted: data collection on management and environment, scoring, practical demonstration with producers, and debriefing. Our tool helped to detect problems and to discuss these problems with the producers. Six months after the on-farm visit, many of the recommended practices had been implemented.

Relationship between female fertility and production traits in Canadian Holsteins. By Sewalem et al., page 4427. Genetic correlations between milk production (TD90M) and some female fertility traits (56-d nonreturn rate in cows, calving to first service, and first service to conception) were estimated. The effect of including TD90M or heifer nonreturn rate as a correlated trait on the genetic evaluation of cow fertility traits in Canadian Holsteins was also investigated. The result showed undesirable correlation between milk production and fertility traits. Including TD90M on the genetic evaluation of calving to first service and first service to conception increased the genetic trend. Including either TD90M or heifer nonreturn rate on 56-d nonreturn rate in cows evaluation yielded similar results.