Commercial Cow Research Articles

The accuracies of DNA-based estimates of genetic merit derived from Angus or multibreed beef cattle training populations1,2,3

Several organizations have developed prediction models for molecular breeding values (MBV) for quantitative growth and carcass traits in beef cattle using Bovine SNP50 genotypes and phenotypic or EBV data. Molecular breeding values for Angus cattle have been developed by IGENITY, Pfizer Animal Genetics, and a collaboration between researchers from Iowa State University and the University of Missouri-Columbia (ISU/UMC). The U.S. Meat Animal Research Center (USMARC; Clay Center, NE) has also developed MBV for 16 cattle breeds using 2 multibreed populations, the Germplasm Evaluation (GPE) Program and the 2,000 Bull Project (2K(ALL)), and 2 single breed subpopulations of the 2,000 Bull Project, Angus (2K(AN)) and Hereford (2K(HH)). In this study, these MBV were assessed relative to commercial ranch EBV estimated from the progeny phenotypes of Angus bulls naturally mated in multisire breeding pastures to commercial cows: 121 for USMARC MBV, 99 for ISU/UMC MBV, and 29 for IGENITY and Pfizer MBV (selected based on number of progeny carcass records). Five traits were analyzed: weaning weight (WW), HCW, marbling score (MS), rib-eye muscle area (RE), and, for IGENITY and Pfizer only, feedlot ADG. The average accuracies of MBV across traits were 0.38 ± 0.05 for IGENITY, 0.61 ± 0.12 for Pfizer, 0.46 ± 0.12 for ISU/UMC, 0.16 ± 0.04 for GPE, 0.26 ± 0.05 for 2K(ALL), 0.24 ± 0.04 for 2K(AN), and 0.02 ± 0.12 for 2K(HH). Angus-based MBV (IGENITY, Pfizer, ISU/UMC, and 2K(AN)) explained larger proportions of genetic variance in this population than GPE, 2K(ALL), or 2K(HH) MBV for the same traits. In this data set, IGENITY, Pfizer, and ISU/UMC MBV were predictive of realized performance of progeny, and incorporation of that information into national genetic evaluations would be expected to improve EPD accuracy, particularly for young animals.

Comparison of estrone and 17β-estradiol levels in commercial goat and cow milk

Increased levels of estrogen metabolites are believed to be associated with cancers of the reproductive system. One potential dietary source of these metabolites that is commonly consumed worldwide is milk. In North America, dairy cows are the most common source of milk; however, goats are the primary source of milk worldwide. In this study, the absolute concentrations of unconjugated and total (unconjugated plus conjugated) estrone (E1) and 17β-estradiol (E2) were compared in a variety of commercial cow milks (regular and organic) and goat milk. A lower combined concentration of E1 and E2 was found in goat milk than in any of the cow milk products tested. The differences in E1 and E2 levels between regular and organic cow milks were not as significant as the differences between goat milk and any of the cow milk products. Goat milk represents a better dietary choice for individuals concerned with limiting their estrogen intake.

Assessment of α-tocopherol content in cow and goat milk from the Serbian market

The present paper reports determination of ?-tocopherol in commercial cow, raw cow and goat milk, as well as estimation of its nutritive value based on ?-tocopherol content. Quantification was done by reversed-phase HPLC with fluorescence detection (ex 295 nm, em 330 nm) and with UV detector set at 286 nm and 292 nm. The method of milk sample preparation consisted of alkaline saponification with 30% KOH, denaturation of lipoproteins with methanol followed by liquid-liquid extraction with diethyl-ether. Recovery values of the extraction method were 78.5, 86.7 and 91.0% for three standard addition levels. Analyzed commercial low-fat milk samples had significant lower ?-tocopherol levels than milk with higher fat content. ?-tocopherol concentration below 0.30 ?g/ml in low-fat cow milk and 0.83-0.86 ?g/ml in whole milk were detected. Raw goat milk had much more ?-tocopherol (1.25 ?g/ml) compared with commercial and raw cow milk with similar fat content.

The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer

Prostate cancer (PCa) is dependent on androgen receptor signaling and aberrations of the PI3K-Akt-mTORC1 pathway mediating excessive and sustained growth signaling. The nutrient-sensitive kinase mTORC1 is upregulated in nearly 100% of advanced human PCas. Oncogenic mTORC1 signaling activates key subsets of mRNAs that cooperate in distinct steps of PCa initiation and progression. Epidemiological evidence points to increased dairy protein consumption as a major dietary risk factor for the development of PCa. mTORC1 is a master regulator of protein synthesis, lipid synthesis and autophagy pathways that couple nutrient sensing to cell growth and cancer. This review provides evidence that PCa initiation and progression are promoted by cow´s milk, but not human milk, stimulation of mTORC1 signaling. Mammalian milk is presented as an endocrine signaling system, which activates mTORC1, promotes cell growth and proliferation and suppresses autophagy. Naturally, milk-mediated mTORC1 signaling is restricted only to the postnatal growth phase of mammals. However, persistent consumption of cow´s milk proteins in humans provide highly insulinotropic branched-chain amino acids (BCAAs) provided by milk´s fast hydrolysable whey proteins, which elevate postprandial plasma insulin levels, and increase hepatic IGF-1 plasma concentrations by casein-derived amino acids. BCAAs, insulin and IGF-1 are pivotal activating signals of mTORC1. Increased cow´s milk protein-mediated mTORC1 signaling along with constant exposure to commercial cow´s milk estrogens derived from pregnant cows may explain the observed association between high dairy consumption and increased risk of PCa in Westernized societies. As well-balanced mTORC1-signaling plays an important role in appropriate prostate morphogenesis and differentiation, exaggerated mTORC1-signaling by high cow´s milk consumption predominantly during critical growth phases of prostate development and differentiation may exert long-term adverse effects on prostate health. Attenuation of mTORC1 signaling by contemporary Paleolithic diets and restriction of dairy protein intake, especially during mTORC1-dependent phases of prostate development and differentiation, may offer protection from the most common dairy-promoted cancer in men of Western societies.

Lack of biologically active estrogens in commercial cow milk

Recently, many studies have investigated potential estrogenic compounds in the human diet. Several of these investigations have studied cow milk, a mainstay of the diets of both young and old. In vitro studies have determined that estrogens can be found in milk, and that the concentration of estrogen may be correlated to the fat content in the milk. Regardless, the majority of these studies have concluded that the levels of estrogens in milk are too low to have a physiological effect. However, a recent study found that commercial 1% cow milk was uterotrophic in rats, suggesting that it contained biologically significant levels of estrogen. Using the rat model, we tested milk samples from commercial sources and with varying fat content for estrogenic activity. Ovariectomized female rats were given milk ad libitum for a period of 2 wk. After 12 d of treatment, rats were tested sequentially in an open field and an elevated plus maze to determine any effect of milk on anxiety levels. Upon completion of the behavior testing, uterine weights were examined. Regardless of milk type, no difference was observed in daily volume of milk consumed. Contrary to previous publications, no differences existed in either the behavior or the uterine weights between animals that consumed any milk type and the negative controls. These results demonstrated that none of the commercial milk types that we tested contained biologically significant estrogenic activity.

FSH withdrawal improves developmental competence of oocytes in the bovine model

Combinations of genetic, environmental, and management factors are suspected to explain the loss in fertility observed for over 20 years in dairy cows. In some cases, IVF is used. When compared with in vivo embryo production, IVF resulted in low success rates until the FSH coasting process (FSH starvation after superstimulation) was introduced in 2002. Increased competence associated with FSH withdrawal of aspirated oocyte for in vitro maturation and IVF has not been optimized nor explained yet. The goal here was to determine and characterize the optimal oocyte competence acquisition window during the coasting period by determining blastocyst rates and follicular cohort development. Commercial milking cycling cows (n=6) were stimulated with 3 days of FSH (6×40 mg NIH Folltropin-V given at 12 h intervals) followed by a coasting period of 20, 44, 68, or 92 h. Each animal was exposed to the four conditions and served as its own control. At the scheduled time, transvaginal aspirations of immature oocytes were performed followed by IVF of half the oocytes. The outcomes were as follows: i) FSH coasting was optimal at a defined period: between 44 and 68 h of coasting; ii) The best estimated coasting duration was ∼54±7 h; iii) Under these conditions, the best statistical blastocyst rate estimation was ∼70%; iv) Between 44 and 68 h of coasting, follicle size group proportions were similar; v) Follicle diameter was not linearly associated with competence. In conclusion, coasting duration is critical to harvest the oocytes at the right moment of follicular differentiation.

Diagnosis of Congenital Bovine Viral Diarrhea Infection in Beef Cow- Calf Herd from Fence-Line Contact

A closed herd of 76 head of Angus and Gelbvieh X commercial cows experienced a series of late gestation abortions, congenital deformities, and weak calves in replacement heifers. History included fence-line contact with a neighboring farm from day 76 to 165 after the beginning of breeding season. The neighbor grazed feeder steers purchased from livestock markets.

Comparative Genomics of Multidrug Resistance-Encoding IncA/C Plasmids from Commensal and Pathogenic Escherichia coli from Multiple Animal Sources

Incompatibility group A/C (IncA/C) plasmids have received recent attention for their broad host range and ability to confer resistance to multiple antimicrobial agents. Due to the potential spread of multidrug resistance (MDR) phenotypes from foodborne pathogens to human pathogens, the dissemination of these plasmids represents a public health risk. In this study, four animal-source IncA/C plasmids isolated from Escherichia coli were sequenced and analyzed, including isolates from commercial dairy cows, pigs and turkeys in the U.S. and Chile. These plasmids were initially selected because they either contained the floR and tetA genes encoding for florfenicol and tetracycline resistance, respectively, and/or the blaCMY-2 gene encoding for extended spectrum β-lactamase resistance. Overall, sequence analysis revealed that each of the four plasmids retained a remarkably stable and conserved backbone sequence, with differences observed primarily within their accessory regions, which presumably have evolved via horizontal gene transfer events involving multiple modules. Comparison of these plasmids with other available IncA/C plasmid sequences further defined the core and accessory elements of these plasmids in E. coli and Salmonella. Our results suggest that the bla CMY-2 plasmid lineage appears to have derived from an ancestral IncA/C plasmid type harboring floR-tetAR-strAB and Tn21-like accessory modules. Evidence is mounting that IncA/C plasmids are widespread among enteric bacteria of production animals and these emergent plasmids have flexibility in their acquisition of MDR-encoding modules, necessitating further study to understand the evolutionary mechanisms involved in their dissemination and stability in bacterial populations.

Role of basophil activation test for monitoring the immunological changes during desnsitization to cow’s milk: a case report

The basophil activation test (BAT) has proven to be a useful tool for the diagnosis of IgE-mediated food allergy and the evaluation of clinical tolerance in food allergic patients. Until now, successful oral desensitization to food allergen has been correlated with changes in cytokine production (IL-4 and INF-γ) and allergen-specific IgE and IgG4 antibodies. We report a case of a 12-year-old male affected by cow’s milk allergy. The diagnosis was based on a positive allergological work-up, included skin prick test with commercial food extracts (Alk-Abello) and fresh cow’s milk (prick-by-prick method), detection in serum of total and specific IgE (ImmunoCAP System, Phadia), basophil activation test and finally a double-blind placebo-controlled food challenge. Skin prick test, specific IgE, BAT and oral food challenge were positive and so we decided to carry on a sublingual-oral desensitization treatment with cow’s milk, performed according to standardized protocol. In order to evaluate the immunological changes occurred during the immunotherapy, we performed further laboratory tests, included the detection in serum of total and specific IgE and BAT at the end of protocol. Desensitization was successfully carried out within 12 months, reaching the maximum dose of 150 ml of cow’s milk without side effects. The patient showed a decrease of specific IgE levels without reaching normal values and an increase of specific IgG4 levels; whereas the BAT starting from a positive value of 59% became negative after 12 months of treatment. This case report shows how it is possible to monitor allergen-specific basophil responses using the flow cytometry in order to identify an acquired tolerance induced by desensitization. Although further studies are needed, it was interesting to note that the basophil activation test seems to be more sensitive and characterized by a close correlation with the clinical tolerance.

Effects of temperament on pregnancy rates to fixed-timed AI in Bos indicus beef cows

The objective of the present experiment was to assess the effects of temperament on pregnancy rates to fixed-time AI (FTAI) in Bos indicus beef cows. A total of 761 multiparous lactating Nelore cows, originated from 4 different commercial cow–calf ranches, were evaluated for BCS and temperament at the time of FTAI (day 0). Temperament was assessed by chute score and exit velocity. Further, individual exit score was calculated by dividing exit velocity results into quintiles and assigning cows with a score from 1 to 5 (exit score: 1=slowest cows; 5=fastest cow). Temperament scores were calculated by averaging cow chute score and exit score. Cows were also classified for temperament type according to temperament score (≤3=adequate temperament, >3=excitable temperament). Pregnancy status was verified by detecting a viable conceptus with rectal ultrasonography approximately 40days after FTAI. Chute score, exit velocity, and temperament score were not correlated to BCS (P>0.31). Hence, BCS did not differ (P=0.30) according to temperament type (4.13 vs. 4.09 for cows with excitable and adequate temperament, respectively; SEM=0.070). Pregnancy rates to FTAI tended to be negatively affected by temperament score (P=0.08), whereas the probability of cows becoming pregnant to FTAI was negatively associated with temperament score (linear effect, P<0.01). Accordingly, pregnancy rates were reduced (P=0.05) in cows with excitable temperament compared to cows with adequate temperament (35.3 vs. 42.8% of pregnant cows/total cows, respectively; SEM=2.85). Pregnancy rates to FTAI were not affected by chute score (P=0.25), although the probability of cows becoming pregnant to FTAI tended to be negatively associated with chute score (linear effect, P=0.07). Pregnancy rates to FTAI were negatively affected by exit score (P=0.05), and the probability of cows becoming pregnant to FTAI was negatively associated with exit score and with actual exit velocity (linear effects, P<0.01). Results from this experiment indicate that excitable temperament is detrimental to pregnancy rates of B. indicus cows assigned to an estrus synchronization+FTAI protocol.

Levels of Se, Zn, Mg and Ca in commercial goat and cow milk fermented products: Relationship with their chemical composition and probiotic starter culture

We determined Se, Zn, Mg and Ca levels in 42 samples of goat and cow fermented milks which are widely consumed in Spain were determined. Atomic absorption spectrometry (hydride generation for Se and flame atomisation for remaining elements) was used as an analytical technique. Reliability of the procedure was checked. Only Mg levels in goat fermented milks were significantly higher to those found in cow fermented milks (p<0.022). Important similarities in concentrations and behaviours for Mg and Ca have been observed. Mg contents were significantly correlated with Zn (r=0.590; p<0.001) and Ca (r=0.344; p<0.028) concentrations, Zn, Mg and Ca levels with protein content (r=0.554, r=0.479, r=0.388, respectively), Mg levels with fats (r=0.403; p=0.011) and Se levels with carbohydrates (r=−0.379; p=0.031). Mineral and macronutrient levels in yogurts with traditional probiotic starter cultures were not significantly different to those found in fermented milks with additional probiotic microorganisms (p>0.05). It was concluded that goat fermented milks are a better source for Mg than cow samples.

Infant Milk Feeding Influences Adult Bone Health: A Prospective Study from Birth to 32 Years

BackgroundPeak bone mass, attained by early adulthood, is influenced by genetic and life-style factors. Early infant feeding and duration of breastfeeding in particular, associate with several health-related parameters in childhood. The aim of this study was to examine whether the effects of early infant feeding extend to peak bone mass and other bone health characteristics at adult age.Methods and FindingsA cohort of 158 adults (76 males) born in Helsinki, Finland, 1975, prospectively followed up from birth, underwent physical examination and bone densitometry to study bone area, bone mineral content (BMC), and bone mineral density (BMD) at 32 years of age. Life-style factors relevant for bone health were recorded. For data analysis the cohort was divided into three equal-size groups according to the total duration of breastfeeding (BF): Short (≤3 months), Intermediate and Prolonged (≥7 months) BF groups. In males short BF is associated with higher bone area, BMC, and BMD compared to longer BF. Males in the Short BF group had on average 4.7% higher whole body BMD than males in the Prolonged BF group. In multivariate analysis, after controlling for multiple confounding factors, the influence of BF duration on adult bone characteristics persisted in males. Differences between the three feeding groups were observed in lumbar spine bone area and BMC, and whole body BMD (MANCOVA; p = 0.025, p = 0.013, and p = 0.048, respectively), favoring the Short BF group. In women no differences were observed.ConclusionsIn men, early infant milk feeding may have a significant impact on adult bone health. A potential explanation is that the calcium and phosphate contents were strikingly higher in formula milk and commercial cow milk/cow milk dilutions as opposed to human milk. Our novel finding merits further studies to determine means to ensure optimal bone mass development in infants with prolonged breastfeeding.

Single-Nucleotide-Polymorphism Genotyping ofCoxiella burnetiiduring a Q Fever Outbreak in The Netherlands

Coxiella burnetii is the etiological agent of Q fever. Currently, the Netherlands is facing the largest Q fever epidemic ever, with almost 4,000 notified human cases. Although the presence of a hypervirulent strain is hypothesized, epidemiological evidence, such as the animal reservoir(s) and genotype of the C. burnetii strain(s) involved, is still lacking. We developed a single-nucleotide-polymorphism (SNP) genotyping assay directly applicable to clinical samples. Ten discriminatory SNPs were carefully selected and detected by real-time PCR. SNP genotyping appeared to be highly suitable for discrimination of C. burnetii strains and easy to perform with clinical samples. With this new method, we show that the Dutch outbreak is caused by at least 5 different C. burnetii genotypes. SNP typing of 14 human samples from the outbreak revealed the presence of 3 dissimilar genotypes. Two genotypes were also present in livestock at 9 farms in the outbreak area. SNP analyses of bulk milk from 5 other farms, commercial cow milk, and cow colostrum revealed 2 additional genotypes that were not detected in humans. SNP genotyping data from clinical samples clearly demonstrate that at least 5 different C. burnetii genotypes are involved in the Dutch outbreak.

Gene flow in a national cross-breeding beef population

Future progress in genetic improvement and the monitoring of genetic resources in beef cattle requires a detailed understanding of the population under selection. This study examines the gene flow in the UK beef population with an uncommon breeding structure involving interaction between the beef and dairy populations. British Cattle Movement Service records were used as the primary source of information, and these data were triangulated with UK government statistics, other industry information sources and existing literature to build up a profile of the UK beef industry. Estimates were made of the breed composition of suckler cows, breeding bulls and the prime slaughter population. Cross-bred animals made up 85% and 94%, respectively, of the commercial beef breeding cow and prime slaughter populations. Holstein/Friesian (through cross-breeding) made up the largest proportion of genes in both these populations with 33% and 28%, respectively. The next five most popular breeds were specialist beef breeds: Limousin (22% and 18%), Charolais (11% and 6%), Simmental (9% and 11%), Angus (7% and 8%) and Belgian Blue (6% and 6%). Combined, the top seven beef breeds accounted for 94% of beef genetics in the prime slaughter population, and 80% of this came from non-native breeds. The influence of dairy breeds in the commercial beef breeding population was highlighted by the fact that 44% of replacement commercial beef breeding females were sourced from beef-sired crosses in the dairy herd, and in total 74% of all maternal grand dams of prime slaughter animals were Holstein/Friesian. The use of selection index technology was also investigated by analysing breeding bull sale results, with the correlation between the terminal sire index and sale price of young breeding bulls being generally moderate but significant, ranging from 0.21 to 0.38 across the major beef breeds. The most influential source of genetics in the commercial suckler beef herd was natural service breeding bulls. These were mostly sourced from pedigree breeders, and accounted for 47.8% of the genetics in the prime beef population. Artificial insemination sires were responsible for 16.6% of prime beef genetics, with the remaining 35.6% coming from dairy breeds, 95% of which was Holstein/Friesian.

Profitability of Preconditioning

The objectives of this study were to assess the profitability of preconditioning calves in a commercial beef cow setting, and to determine factors associated with profit from preconditioning. The herd owner identified an overarching goal within the project: to supply a higher quality calf to the feedlot and capture the increased value of that calf to improve profitability. Results indicated that preconditioning was profitable for this example herd, with an average return to labor and management of $80.70 per calf per year for preconditioning. Returns ranged from $26.04 to $116.48 per calf per year, and profitability improved as the manager's experience with managing the preconditioning component of the operation increased. The preconditioning enterprise was profitable in each of the 11 years of the study. Factors related to profit from preconditioning included average daily gain, days-on-feed, cost of gain, and feed cost of gain. Health concerns in this example were minimal; morbidity was 0.09% (1 of 1,103) and mortality was 0.27% (3 of 1,103). Overall, returns to preconditioning were primarily due to added weight sold (63% of return to preconditioning) with the preconditioning health sales price advantage adding the remaining 37%.

Serum micronutrient concentrations in beef cows before and after the summer grazing season

Serum concentrations of Cu, Mn, Mo, Se, vitamin A, and vitamin E were measured at the start and at the end of the summer grazing season in an observational field study of 791 commercial beef cows from 40 cow-calf herds from five community pastures. Copper and vitamin A were higher in the fall (P &lt; 0.001), and Mo (P &lt; 0.001) and selenium (P &lt; 0.001) were lower in the fall compared with the spring. Cows aged 10-14 yr had lower concentrations of vitamin A (P &lt; 0.001) and vitamin E (spring: P = 0.010; fall: P &lt; 0.001) than cows aged 4-9 yr. Cows with thin pre-breeding body condition scores were more likely to have lower pre-breeding Cu concentrations than cows that were not thin (P = 0.044). Cows that were thin at the end of the grazing season were more likely to have lower vitamin A concentrations at this time than cows that were not thin (P = 0.033). Trace mineral supplementation given before calving was associated with higher spring concentrations of Cu (P = 0.007). Season of sample collection and the physiological status of the animals should be considered when interpreting the serum micronutrient status of beef cows and developing supplementation programs.

Amino acid needs of lactating dairy cows: Predicting limiting amino acids in contemporary rations fed to high producing dairy cattle in California using metabolic models

The objectives were to predict amino acid (AA) profiles of intestinally delivered protein in California high group ( i.e., lactating but not yet confirmed to be in calf) dairy cattle fed contemporary rations using three metabolic models of dairy cows. This was done in order to predict limiting AA in dairy rations to determine if there was enough consistency in the nutrient profiles of these rations to support a common ruminally protected (RP) AA package to supplement similar rations. Nutrient profiles of 16 commercial high group dairy cow rations were evaluated, and limiting AA predicted by the metabolic models ‘Amino Cow’, ‘CPM Dairy’ and ‘Shield’. Higher inclusion levels of corn products in rations increased the contribution of corn CP to the total CP content of the total mixed ration (TMR), from 0.20 to 0.40. Even though the lysine to methionine ratio decreased as more corn CP was included in the TMR, it did not have a major impact on the final predicted AA profile of metabolizable protein (MP), but MP delivery (g/d) to the duodenum was predicted to decrease with increased corn CP levels. None of the models predicted any affect of increased corn CP levels on milk components but, according to Shield, it did have an effect on milk yield which increased when the ratio of lysine to methionine in MP decreased. The sequence of AA limitation among rations was the same within model, but differed substantially among models. Methionine, isoleucine and lysine were predicted to be most limiting according to Amino Cow, CPM Dairy and Shield, respectively. There appears to be sufficient consistency in nutrient profiles among rations to support a ruminally protected AA complex to balance the model predicted AA profile in order to increase animal productivity and efficiency of utilization of nutrients. There is no absolute way to decide which model predictions are most correct. However because Shield predictions suggested a higher correlation between Lys and Met in MP and production, as well as predicted AA ratios to milk responses related to these ratios, use of the Shield predicted AA package is supported.

Analyses of diverse mammals’ milk and lactoferrin glycans using five pathogenic bacterial lectins

Milk indigested glycans hamper infections by blocking pathogen adhesion to babies’ cells via lectins (sugar-binding proteins). This study describes usage of five pathogenic bacterial lectins and two plant lectins for analyses of alpaca, buffalo, camel, cow, dog, fallow deer, giraffe, goat, horse, human, rabbit, and sheep milks, and also commercial human and cow milk lactoferrins. The lectins used differentially reacted with the 12 milks – most strongly with humans’ ones. Most of them (excluding Pseudomonas aeruginosa galactophilic PA-IL) were also sensitive to the human and cow lactoferrins. The fucophilic bacterial lectins were most sensitive to human lactoferrin, while the mannophilic ones – to the cow’s. The actual function of bacterial lectins in pathogen adhesion and their non-glycosylated structures (evading non-specific interactions) are advantageous for such studies. This study shows the efficiency of the bacterial lectins for milk analyses: differentiating between the diverse milks, estimating their anti-infection potentials, and probing their active glycans.

Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows

Modern genetically improved dairy cows continue to lactate throughout almost the entire pregnancy. Therefore, recent commercial cow's milk contains large amounts of estrogens and progesterone. With regard to the exposure of prepubertal children to exogenous estrogens, the authors are particularly concerned about commercial milk produced from pregnant cows. The purpose of the present study was therefore to examine concentrations of serum and urine sex hormones after the intake of cow milk. Subjects were seven men, six prepubertal children, and five women. The men and children drank 600 mL/m(2) of cow milk. Urine samples were collected 1 h before the milk intake and four times every hour after intake. In men the serum samples were obtained before and 15, 30, 45, 60, 90 and 120 min after milk intake. Women drank 500 mL of cow's milk every night for 21 days beginning on the first day of the second menstruation. In three successive menstrual cycles, the day of ovulation was examined using an ovulation checker. After the intake of cow milk, serum estrone (E1) and progesterone concentrations significantly increased, and serum luteinizing hormone, follicle-stimulating hormone and testosterone significantly decreased in men. Urine concentrations of E1, estradiol, estriol and pregnanediol significantly increased in all adults and children. In four out of five women, ovulation occurred during the milk intake, and the timing of ovulation was similar among the three menstrual cycles. The present data on men and children indicate that estrogens in milk were absorbed, and gonadotropin secretion was suppressed, followed by a decrease in testosterone secretion. Sexual maturation of prepubertal children could be affected by the ordinary intake of cow milk.

Effect of Wagyu- versus Angus-sired calves on feedlot performance, carcass characteristics, and tenderness

Wagyu-sired (n = 20) and Angus-sired (n = 19) steers and heifers were used to compare the effects of sire breed on feedlot performance, carcass characteristics, and meat tenderness. Calves were weaned at 138 +/- 5 d of age and individually fed a finishing diet consisting of 65% whole corn, 20% protein/vitamin/mineral supplement, and 15% corn silage on a DM basis. Heifers and steers were slaughtered at 535 and 560 kg of BW, respectively. Carcasses were ribbed between the 12th and 13th (USDA grading system) and the 6th and 7th ribs (Japanese grading system) to measure fat thickness, LM area (LMA), and intramuscular fat (IMF). Two steaks were removed from the 12th rib location and aged for 72 h and 14 d to determine Warner-Bratzler shear force and cooking loss. Sire breed x sex interactions were not significant (P > 0.05). Angus-sired calves had greater (P < 0.05) ADG and DMI than Wagyu. Wagyu-sired calves had improved (P < 0.05) feed efficiency than Angus. Sire breed did not affect (P > 0.20) HCW, 12th-rib fat, or USDA yield grade. Carcasses of Wagyu had greater (P = 0.0001) marbling scores at the 12th rib than those of Angus (770.9 vs. 597.3 +/- 41.01, respectively). Carcasses of Wagyu also had greater (P < 0.02) 12th-rib IMF and 6th-rib IMF than Angus, resulting in a greater proportion of carcasses grading Prime (65.0 vs. 21.1%; P = 0.006). Carcasses from Wagyu tended (P = 0.08) to have greater LMA at the 12th rib, whereas Angus carcasses had greater (P < 0.05) LMA at the 6th rib. Steaks from Angus and Wagyu had similar (P > 0.50) tenderness at aging times of 72 h and 14 d. Cooking loss was greater (P < 0.01) for Angus than Wagyu steaks at 72 h and 14 d. Using Wagyu sires vs. Angus sires on British-based commercial cows combined with early weaning management strategies has the potential to produce a product with greater marbling, but is unlikely to significantly enhance tenderness.