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• Male-sexed semen can increase numbers of heavier and faster-growing male offspring • Artificial insemination is not commonly practised in extensive beef cow herds • Sexed semen increased breeding costs by up to 91% compared with natural mating only • Increased income from heavier, male offspring did not justify the higher breeding costs • Male-sexed semen was not profitable for the extensive beef cow herd modelled Male-sexed semen can be used in beef cow herds to increase the number of heavier and faster-growing male offspring. The use of sexed semen requires artificial insemination (AI) which has limited use in extensive beef systems due to practical constraints and the additional breeding costs incurred. The objective of this study was to use bio-economic simulation modelling to predict the profitability of using sexed semen via fixed time AI for a New Zealand hill country farm system based around a beef cow herd. When modelling self-replacing Angus herds male-sexed Simmental semen was utilised across 43% of mixed-age cows then follow up Simmental bulls were used for subsequent natural mating. To generate replacement Angus heifers, first time calvers and remaining mixed-age cows were bred with unsexed Angus semen and then naturally bred with Angus bulls if they did not conceive. All mixed-age cows in an AngusxHolstein-Friesian herd with a bought-in replacements policy were bred with male-sexed Simmental semen followed by Simmental bulls. First time AngusxHolstein-Friesian calvers were bred with unsexed Angus semen followed by Angus bulls. Sire breed was assumed to have the same effects on offspring production regardless of use through AI or natural mating. Herds using sexed semen were assumed to undergo synchronised fixed-time AI which resulted in a more condensed calving spread and 3% heavier average weaning weights due to calves being predominantly male and on average seven days older. Total breeding costs were higher for herds using sexed semen via AI at NZD 135-166 /cow compared with NZD 67-102 /cow for herds using only natural mating. Increases in breeding costs were relatively larger than any additional income for all herds using sexed semen via AI, resulting in lower COS (cash operating surplus) compared with herds using all-natural mating. The COS of using sexed semen via AI were 14% (COS = NZD 280 /ha) and 9% (COS = NZD 405 /ha) lower than all-natural mating using Simmental sires for the purebred Angus (COS = NZD 325 /ha) and AngusxHolstein-Friesian crossbred (COS = NZD 444 /ha) cow herds, respectively. It appears producing more fast-growing male calves through use of sexed semen via AI is not currently an economically feasible option for beef producers under extensive production systems. Future analysis could include benefits of access to higher genetic merit sires as the combination of superior genes and more male offspring may be more profitable than all-natural mating. [ABSTRACT FROM AUTHOR]

Foram utilizados 71 animais pertencentes a dois grupos genéticos com diferentes potenciais de crescimento, ½ Angus - ½ Nelore (AN) e ½ Simental - ½ Nelore (SN). Esses animais, pertencentes a um projeto amplo denominado Projeto Cruzamento Embrapa 1, foram submetidos a sete tratamentos de castração. Observou-se que os animais SN permaneceram 14 dias a mais, em confinamento, para que fossem abatidos com o mesmo grau de acabamento que os AN (131 dias versus 117 dias, respectivamente). As demais características estudadas, peso de abate, peso de carcaça fria, rendimento de carcaça e área de olho-de-lombo, não foram influenciadas pelo grupo genético e apresentaram, nessa mesma seqüência, médias iguais a 471 kg e 476 kg, 266 kg e 274 kg, 58,13% e 57,46% e 72,71 cm² e 75,79 cm² para AN e SN, respectivamente. As comparações entre as médias dos diferentes tratamentos foram realizadas utilizando-se seis contrastes. Verificou-se que os animais inteiros permaneceram 25 dias a mais em confinamento do que aqueles castrados no nascimento (136 dias versus 111 dias, respectivamente). No entanto, estes animais apresentaram peso médio de abate superior àqueles observados para os animais castrados no nascimento (515 kg versus 463 kg, respectivamente). Animais castrados no nascimento permaneceram mais tempo em confinamento do que aqueles castrados na desmama ou com um ano de idade (111 dias versus 95 dias, respectivamente). Os animais confinados logo após a desmama, como era de se esperar, foram aqueles que permaneceram mais tempo em confinamento (181 dias). Por serem animais jovens, um ano mais novos que os demais, esse maior tempo em confinamento não refletiu em pesos de abate mais elevados (455 kg). O rendimento médio de carcaça, independente do grupo genético e tratamento, foi de 57,79%.

The use of Brahman in cow-calf production offers some adaptation to the harsh characteristics of endophyte-infected tall fescue. Criollo breeds, such as the Romosinuano, may have similar adaptation. The objectives were to estimate genetic effects in Romosinuano, Angus, and crossbred cows for their weights, weights of their calves, and ratios (calf weight:cow weight and cow weight change:calf weight gain) across lactation and to assess the influence of forage on traits and estimates. Cows (n = 91) were bred to Charolais bulls after their second parity. Calves (n = 214) were born from 2006 to 2009. Cows and calves were weighed in early (April and June), mid- (July), and late lactation (August and October). Animal was a random effect in analyses of calf data; sire was random in analyses of cow records and ratios. Fixed effects investigated included calf age, calf sex, cow age-year combinations, sire breed of cow, dam breed of cow, and interactions. Subsequent analyses evaluated the effect of forage grazed: endophyte-free or endophyte-infected tall fescue. Estimates of maternal heterosis for calf weight ranged from 9.3 ± 4.3 to 15.4 ± 5.7 kg from mid-lactation through weaning (P < 0.05). Romosinuano direct effects (of the cow) were -6.8 ± 3.0 and -8.9 ± 4.2 kg for weights recorded in April and June. Calf weights and weight gains from birth were greater (P < 0.05) for calves of cows grazing endophyte-free tall fescue except in mid-summer. Cow weight change from April to each time was negative for Angus cows and lower (P < 0.05) than other groups. Cows grazing endophyte-free tall fescue were heavier (P < 0.05) at all times but had more weight loss in late lactation. Angus cows had the lowest (P < 0.05) ratios (negative) of cow weight change:calf weight gain, indicating an energy-deficit condition. Cows grazing endophyte-free tall fescue had more negative (P < 0.05) values for this trait but not in early lactation (P < 0.05). Estimates of heterosis ranged from 12.8 ± 9.5 to 28.6 ± 9.4 kg for cow weight, 7.9 ± 3.0 to 15.8 ± 5.0 kg for cow weight change, and 0.07 ± 0.03 to 0.27 ± 0.1 for cow weight change:calf weight gain. Direct Romosinuano effects ranged from 14.8 ± 4.2 to 49.8 ± 7.7 kg for cow weight change and 0.2 ± 0.04 to 0.51 ± 0.14 for cow weight change:calf weight gain. The adaptive ability of Romosinuano in temperate fescue regions may be favorable with respect to relative cow and calf weight but may be a consequence of lower milk-producing ability. [ABSTRACT FROM AUTHOR]

Subjective scores ( n =2603) representing (1) the shedding and regrowth of winter coat and (2) total quantity of hair were recorded monthly for 2 yr for 135 Angus cows. Shedding scores of 1 indicated summer coats (all winter coat shed) and 5 indicated complete winter coats. Quantity scores of 1 and 5 indicated minimal and maximal amounts of hair in the coat, respectively. Scores of 2 through 4 for respective traits indicated intermediate conditions. A trigonometric function representing a sinusoid process was fitted to the residuals of scores across time: A sin [ B ( t − C ) ] + D , where A represents the height of peaks in the oscillatory function above a centralized baseline in the Cartesian plane; B represents the angular frequency, that is, the rate of change of scores across a complete fundamental cycle of the process; C represents the horizontal shift in the cycle; D represents the vertical offset of the function. The time dimension in months is represented as t . Parameters for this function were estimated for the two traits using least squares nonlinear regression procedures (1) across all data, (2) within cow age categories, and (3) within groups of cows representing distinct maternal lineages. In all cases, parameters representing amplitude ( A ) and angular frequency ( B ) seemed to be estimated most reliably (as indicated by magnitude of SE) and the parameter representing the vertical offset seemed to be estimated least reliably. The numerically larger estimate of the amplitude parameter ( A ) for winter coat shedding and regrowth score relative to the quantity of hair score suggested that it better characterized the process, as well as differences among cow age groups or maternal lineages. For both traits within all groupings of records the parameter representing the horizontal phase shift ( C ) appeared to be most informative: curves for younger cows were shifted to the right in the time space, indicating later shedding of winter coat. The phase shift parameter also best characterized differences in the process for cows in different maternal lineages; however, numerical differences in the parameter estimates representing amplitude ( A ) and angular frequency ( B ) also appeared to be responsible for the distinctiveness of group curves. Curves visually represented the shedding of winter coats (April–July in the time parameter space) better than the winter regrowth process. There may be value in considering parameters of such curves in some genetic improvement strategies for enhancing cow adaptability to local environmental conditions. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess carcass and meat quality of Black Angus × White Lamphun (A×W) in comparison to Black Angus × Holstein Friesian (A×H) crossbred cattle. In this experiment, sixteen Angus crossbred cattle, eight from each crossbred type, were randomly selected at an average age 20-24 month for slaughter under standard condition. Slaughter weight, carcass quality and proportions of commercial prime retail cuts were determined. The Longissimus dorsi muscle (LD) was selected to evaluate meat quality. Carcass yield (proportion of live weight) was higher ( P <0.01) with the A×H than the A×W crossbred. No significant differences were observed between A×H and A×W for hot and chilled carcass weight, carcass length, back fat thickness and loin eye area. The A×W crossbred was superior ( P <0.05) compared with A×H in chuck, shot rib and sir loin percentage. The lightness (L*) of the LD of A×W was higher ( P <0.01) and redness (a*) as well as protein content was lower ( P <0.05) than in A×H. Drip loss, yellowness (b*), fat, and moisture content were not significantly different between the two crossbred types. Thiobarbitiric acid reactive substance (TBARS) levels were increased with storage period in every group, but this at a lower level with the A×W. In conclusion, A×W was superior to A×H incarcass and meat quality, with similar carcass weights at lower dressing percentage. So, promoting of A×W, is a promising first step in creating improved genotypes suitable to cover the demands of the livestock industry of Thailand at concomitantly lower production costs for the farmers. [ABSTRACT FROM AUTHOR]

Tornadoes have the potential to cause significant destruction and loss of life in many regions across Canada. Accordingly, these hazards are essential to consider for a comprehensive emergency management plan. Following a suspected tornadic event, damage surveys are conducted by Environment Canada to determine the extent and severity of damage in order to assign an Enhanced Fujita scale rating. The purpose of this paper is to investigate the process involved in conducting storm damage surveys, and to assess how information gathered during these surveys is used. Primary research for this study involved conducting semi-structured interviews with Environment Canada damage surveyors from various provinces ( n =10) and wind engineering researchers from a large public university in Canada ( n =2), as well as an onsite observation of a damage survey conducted in Angus, Ontario after a tornado struck on 17 June 2014. The results of this study underscored the subtle but important differences between storm damage surveys conducted in the United States and Canada. It was also found that the majority of damage surveys are now conducted remotely through photos, videos, and telephone interviews with key witnesses. Finally, damage surveys were found to be a critical component of the disaster management cycle by contributing to both risk reduction and preparedness. Introducing sophisticated technologies such as mobile devices and applications, as well as using volunteered geographic information to display damage reports on a web-map, could further improve the damage surveying process in both Canada and abroad. [ABSTRACT FROM AUTHOR]

The purpose of this study was to estimate correlations between purebred and F1 crossbred performance to verify the appropriateness of current models used in multibreed selection. Records on birth weight (WB) and weaning weight (WW) from purebred Limousins (LIM) and Limousin × Angus progeny (F1) were used to estimate genetic parameters using a multiple-trait (purebred and F1 weights were different traits) approach. For WB, there were 148,647 records for LIM and 17,981 for F1, and for WW, there were 81,585 records for LIM and 21,778 for F1. The fixed effect in models for LIM and F1 animals was contemporary group. Random effects for LIM animals were direct genetic, maternal genetic, and maternal permanent environment effects. Random effects for F1 were sire and dam. The pedigree for Angus dams used for crossing was unavailable and therefore these dams were assumed unrelated. The direct h2 estimates (SE) for purebred animals were 0.41 (0.05) and 0.24 (0.02) for WB and WW, respectively. For F1, the same estimates were 0.22 (0.09) and 0.32 (0.05). Genetic correlations estimates between purebreds and crossbreds were 0.84 (0.07) and 0.64 (0.18) for WB and WW, respectively. The genetic correlation for WW estimated in this study suggests that F1 and purebred information for this trait should not be treated, genetically, as the same trait due to different genetic effects molding it. However, the genetic correlation for WB was much higher, indicating that this trait in purebreds and F1 is essentially the same trait. [ABSTRACT FROM AUTHOR]

The objective was to determine the effects of a decreased interval of progesterone on the ovulatory follicle prior to fixed-timed artificial insemination (FTAI) in a 7 & 7 Synch estrous synchronization protocol using estrus expression (EE), FTAI pregnancy rates (AIPR) on 37±2d, and overall pregnancy rates (OPR) after a 60d bull exposure 90±2d determined via ultrasound. Using conventional Angus semen, multiparous Angus-cross cows (n=201) from two locations were randomized by age and days post-partum into two treatments. Both treatments used a controlled internal drug releasing device (Eazi-breedTM CIDR; 1.38g progesterone) inserted intravaginally -14d of the protocol simultaneous to administration of prostaglandin F2a (PGF; 500µg cloprostenol sodium; Estrumate®). In the first treatment (7&7), gonadotropin-releasing hormone (GnRH; 86µg gonadorelin; Fertagyl®) was administered on -7d. In the second treatment (8&6), GnRH was administered on -6d. Both treatments were then administered PGF simultaneous to CIDR removal on 0d, 66±2h prior to FTAI and administration of GnRH. EE was determined at the time of artificial insemination using an EstrotectTM patch (Rockway Inc., Spring Valley, WI). EE was signified as a patch with 50% or more of the color rubbed off or missing. Subsequently, a patch with less than 50% of the color rubbed off, was not. AIPR, OPR and EE were analyzed by treatment using the GLIMMIX procedure on SAS 9.4 (SAS Institute Inc., Cary, NC.). There was a significant effect on EE (P=0.01), a tendency on PR (P=0.08), and no effect on OPR (P=0.53) by treatment. EE, AIPR, and OPR for 7&7 were 95±2.1%, 82±3.7% and 96.7±1.7% and for 8&6 were 86±4.0%, 91±3.1% and 98±1.5%, respectively. In conclusion, the altered timeframe of GnRH administration affected EE and tended to affect PR in multiparous beef cows, suggesting that GnRH administration may improve PR when administered 6d, instead of 7d, prior to CIDR removal. [ABSTRACT FROM AUTHOR]

Genomically estimated breeding values (GEBV) for Angus beef cattle are available from at least 2 commercial suppliers (Igenity [http://www. igenity.com] and Zoetis [http://www.zoetis.com]). The utility of these GEBV for improving genetic evaluation depends on their accuracies, which can be estimated by the genetic correlation with phenotypic target traits. Genomically estimated breeding values of 1,032 Angus bulls calculated from prediction equations (PE) derived by 2 different procedures in the U.S. Angus population were supplied by Igenity. Both procedures were based on Illuminia BovineSNP50 BeadChip genotypes. In procedure sg, GEBV were calculated from PE that used subsets of only 392 SNP, where these subsets were individually selected for each trait by BayesCπ. In procedure rg GEBV were calculated from PE derived in a ridge regression approach using all available SNP. Because the total set of 1,032 bulls with GEBV contained 732 individuals used in the Igenity training population, GEBV subsets were formed characterized by a decreasing average relationship between individuals in the subsets and individuals in the training population. Accuracies of GEBV were estimated as genetic correlations between GEBV and their phenotypic target traits modeling GEBV as trait observations in a bivariate REML approach, in which phenotypic observations were those recorded in the commercial Australian Angus seed stock sector. Using results from the GEBV subset excluding all training individuals as a reference, estimated accuracies were generally in agreement with those already published, with both types of GEBV (sg and rg) yielding similar results. Accuracies for growth traits ranged from 0.29 to 0.45, for reproductive traits from 0.11 to 0.53, and for carcass traits from 0.3 to 0.75. Accuracies generally decreased with an increasing genetic distance between the training and the validation population. However, for some carcass traits characterized by a low number of phenotypic records (weight, intramuscular fat, and eye muscle area), accuracies were observed to increase but had large SE. Therefore, Igenity GEBV can be useful to Australian Angus breeders, either for blending EBV or as the sole basis for selection decisions if no other information is available. However, for carcass traits, additional phenotypic data are required. [ABSTRACT FROM AUTHOR]

The objective of this work was to estimate heritability of each of 5 subjectively measured aspects of temperament of cattle and the genetic correlations of pairs of those traits. From 2003 to 2013, Nellore-Angus F t and F3 calves ( n = 1,816) were evaluated for aspects of temperament at an average 259 d of age, which was approximately 2 mo after weaning. Calves were separated from a group and subjectively scored from 1 (calm, good temperament) to 9 (wild, poor temperament) for aggressiveness (willingness to hit an evaluator), nervousness, flightiness, gregariousness (willingness to separate from the group), and a distinct overall score by 4 evaluators. Data were analyzed using threshold and linear models with additive genetic random effects. Two-trait animal models (nonthreshold) included the additive genetic covariance for pairs of traits and were used to estimate additive genetic correlations. Contemporary groups ( n = 104) represented calves penned together for evaluation on given evaluation days. Heifers had greater (worse) means for all traits than steers (P < 0.05). The regression of score on age in days was included in final models for flightiness (P = 0.05; -0.006 ± 0.003) and gregariousness (P = 0.025; - 0.007 ± 0.003). Estimates of heritability were large (0.51, 0.4, 0.45, 0.49, and 0.47 for aggressiveness, nervousness, flightiness, gregariousness, and overall temperament, respectively; SE = 0.07 for each). The ability to use this methodology to distinctly separate different aspects of calf temperament appeared to be limited, as estimates of additive genetic correlations were near unity for all pairs of traits; estimates of phenotypic correlation ranged from 0.88 ± 0.01 to 0.99 ± 0.002 for pairs of traits. Distinct subsequent analyses indicated a significant negative relationship of 4 of the various temperament scores with weight at weaning (regression coefficients ranged from -0.008 ± 0.002 for nervousness, flightiness, and gregariousness to -0.003 ± 0.002 for aggressiveness). In subsequent analyses, the regression of temperament trait on sequence of evaluation within a pen was highly significant and solutions ranged from 0.05 ± 0.007 for aggressiveness to 0.08 ± 0.007 for all other traits. The apparent large additive genetic variance for any one of these traits may be useful in identification of genes responsible for differences in cattle temperament. [ABSTRACT FROM AUTHOR]

The objectives of this work were to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbred and crossbred cows with Angus and Brahman, to estimate heterosis and direct and maternal genetic breed effects, and to describe calf loss, cow removals from the project, the occurrence of calving difficulty, inadequate calf vigor at birth, and udder problems by cow breed groups. Cows (n = 404) were bom from 2002 to 2005. After their first exposure to bulls as young cows, in all subsequent breeding seasons crossbred cows were bred to bulls of the third breed, and straightbred cows were bred to bulls of the other two breeds. Calving records (n = 1,484) from 2005 to 2011 were used to create calving and weaning rate and calving interval (excluding the interval between 2 and 3 yr of age). Final models for these traits included sire breed-dam breed interaction, cow age within year, and random animal effects. Heterosis estimates for Romosinuano-Brahman calving and weaning rate were 0.06 ± 0.02 and 0.07 ± 0.03 (P < 0.05); those for Brahman-Angus were twice as large (0.13 ± 0.03 and 0.14 ± 0.03, respectively; P < 0.001). Estimates of Brahman direct effects on calving and weaning rate were -0.12 ± 0.04 and -0.14 ± 0.05 (P < 0.05); however, Angus direct effects were beneficial for both traits (0.1 ± 0.05, P < 0.05). The effect of heterosis was to reduce calving interval by -49.2 ± 9.9 and -37.2 ± 9.7 d for Romosinuano-Brahman and Brahman-Angus, respectively (P < 0.001). Romosinuano and Fj cows sired by Romosinuano and out of Angus dams had the most occurrences of difficult births as a proportion of cows that calved (0.028 and 0.025, P = 0.04). Angus-sired crossbred cows and Brahman cows had the most occurrences of udder problems as a proportion of lac-tating cows (0.14 to 0.21, P < 0.04). There were more Brahman-sired cows that died or were culled as a proportion of those cows that began the project (0.1 to 0.28, P < 0.02) than cows in the other breed groups. Romosinuano-Brahman and Romosinuano-Angus cow performance was acceptable, but for most traits, those pairs of breeds had lower heterosis than Brahman-Angus. [ABSTRACT FROM AUTHOR]

This study evaluated, through meta-analysis, the effect of distillers' grains (DG) supplementation to beef cattle on their performance, carcass parameters, and meat fatty acid profile. Eighty-one peer-reviewed publications with 439 treatments means were included in the data set. The effects of DG supplementation to beef cattle were evaluated using weighted mean differences (WMD) between the control group (diets with no DG) and DG group (diets with DG). Heterogeneity was explored by meta-regression and subgroup analysis using genetic type, treatment period, DG type, amount of DG in diet (g DG/kg DM), sulfur in diet (g S/kg DM), ether extract in diet (g EE/kg DM), feed systems (pasture or total mixed ration), and concentrate level in the diet (g/kg DM). Meat fatty acid profile was more affected when DG was fed to crossbreed animals. In Angus animals, DG inclusion to the diets had little effect on meat fatty acid profile whereas, a pronounced reduction was reported in meat omega-6/omega-3 ratio. In response to DG inclusion to the diets, an increase in diet sulfur content up to 6.0 g/kg and ether extract content up to 110 g/kg had no adverse effects on performance, carcass parameters, and meat physicochemical characteristics. Distillers' grains inclusions in amounts between 500 and 600 g DG/kg provided the greatest responses when evaluating carcass parameters and meat fatty acid profile. Increased CLA c9 t11, linolenic acid, and total PUFA and reduced myristic acid concentration in meat were reported when animals were fed diets containing DG., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Linkage disequilibrium (LD) and the persistence of its phase across populations are important for genomic selection as well as fine scale mapping of quantitative trait loci. However knowledge of LD in beef cattle, as well as the persistence of LD phase between crossbreds and purebreds, is limited. The objective of this study was to understand the patterns of LD in Angus, Charolais, and crossbred beef cattle based on 31’073, 32’088 and 33’286 SNP in each population, respectively. Amount of LD decreased rapidly from 0.29 to 0.23 to 0.19 in Angus (AN), 0.22 to 0.16 to 0.12 in Charolais (CH), 0.21 to 0.15 to 0.11 in Crossbreds (C), when the distance range between markers changed from 0-30kb to 30-70kb and then to 70-100kb, respectively. Breeds and chromosomes had significant effects (P

• Using terminal sires in a beef cow herd increases sale prices and feed demand per animal sold. • Selling more of cattle direct to slaughter necessitated reductions in cow herd numbers. • Selling more cattle direct to slaughter was the most economically beneficial strategy explored. • Price premiums and higher weaning rates were also economically beneficial. • These management options can be implemented concurrently in a beef cow herd. New Zealand farmers can choose to breed a proportion of their beef cow breeding herd with terminal breed sires to produce heavier offspring to sell for higher per head prices. However, the heavier weights of terminal offspring also increase their feed demand which may necessitate cow herd size reductions in a system with a fixed feed supply. This study used a bio-economic, system dynamics model to simulate cattle numbers, production, and beef enterprise cash operating surplus (COS) for a self-replacing beef suckler herd of Angus breed cows bred with only Angus sires to produce purebred offspring or a proportion of cows bred with European breed terminal sires (such as Charolais or Simmental). The herd was also modelled with varying calf weaning rates (84 or 90%), with offspring sales occurring either at weaning or at 27 months of age, and in a secondary analysis, with or without price premiums for sales of cattle of at least 75% Angus breed. Total annual beef feed demand was maintained at 40% of total farm feed supply (total farm area of 530 ha) in all scenarios, with the remainder consumed by the on-farm sheep flock. Beef enterprise COS was therefore divided by the beef herd proportion of farm area (212 ha) to derive a per ha COS value. Herd replacement rate was first modelled at 22% allowing for 43% of cows to be bred with terminal sires with a weaning rate of 84%. With a weaning rate of 90% the replacement rate was 18% allowing 60% of cows to be bred with terminal sires. The base scenario with a herd weaning rate of 84% using only Angus sires had a COS of NZD 255 /ha. Relative to the base scenario, use of terminal sires increased COS by the largest amount (COS = NZD 317 /ha), Angus premiums increased COS by a lower amount (COS = NZD 307 /ha), and the higher weaning rate of 90% increased COS by a slightly lesser amount (COS = NZD 302 /ha). Alternatively, these strategies could be implemented concurrently, which was predicted to have the highest COS at NZD 381/ha. These results can inform farmer decision making and farmers can consider the relative profitability potential and practicality of the explored strategies for their breeding herd. [ABSTRACT FROM AUTHOR]

• Beef-dairy crossbred cows sourced from the dairy industry can be farmed as a breeding herd for beef production. • Beef-dairy cows have been observed as lighter than Angus cows while weaning heavier calves. • Feed demand, productivity, and profitability of these breed options were compared using bio-economic modelling. • Beef-dairy herds were 8% to 79% more profitable, depending on offspring sale policies and sire breed choice. • Numbers of breeding cows may reduce to levels which are impractical in this system with fixed feed supply on hill country. Beef-dairy crossbred cows (such as Angus-Friesian) have lighter mature cow weights while weaning heavier calves compared with cows in a typical self-replacing New Zealand Angus breed herd. The objective of this study was to quantify the potential profitability of farming an Angus-Friesian cow herd through modelling the potential changes in cattle numbers, feed demand, production, and beef enterprise economics. The Angus-Friesian cow herd was simulated as purchasing all replacement heifers and was modelled with different sire breeds (Angus or terminal such as Charolais or Simmental) and offspring sale policies (sold at weaning at six months of age or at 27 months of age). Total annual cattle feed demand was maintained at the same level for all modelled scenarios. Angus-Friesian herds had 8% to 79% higher beef enterprise cash operating surplus (COS) compared with the self-replacing Angus herd (COS = NZD 255/ha). For the Angus-Friesian herds, selling all offspring prime (direct to slaughter) at 27 months of age resulted in 20% to 59% higher COS than selling all offspring store (sold at weaning) at weaning at six months old. Utilising terminal breed sires with the Angus-Friesian herd resulted in 10% to 12% higher COS compared with using Angus sires when selling all offspring store at weaning, due to the heavier sale weights and resultant higher per head sale values. However, when selling all offspring prime at 27 months of age the utilisation of Angus sires resulted in 10% to 11% higher COS than using terminal sires, as the lighter weights and thus total feed demand was lower for offspring born to Angus sires allowing for a greater breeding cow numbers (and therefore numbers of offspring sold). Scenarios in which offspring were retained on-farm until 27 months of age increased total feed demand of cattle destined for sale, necessitating reductions in breeding cow numbers to as low as 60% of the base system level, which may inhibit farmers' ability to manage pasture quality. Farmers considering a change to an Angus-Friesian crossbred herd of breeding cows can include the potential herd numbers, feed demand, production, and economic changes predicted in this analysis in their decision making, as well as the practicalities of the explored strategies for designing their farm system. [ABSTRACT FROM AUTHOR]

Background As consumers continue to request food products that have health advantages, it will be important for the livestock industry to supply a product that meet these demands. One such nutrient is fatty acids, which have been implicated as playing a role in cardiovascular disease. Therefore, the objective of this study was to determine the extent to which molecular markers could account for variation in fatty acid composition of skeletal muscle and identify genomic regions that harbor genetic variation. Results Subsets of markers on the Illumina 54K bovine SNPchip were able to account for up to 57% of the variance observed in fatty acid composition. In addition, these markers could be used to calculate a direct genomic breeding values (DGV) for a given fatty acids with an accuracy (measured as simple correlations between DGV and phenotype) ranging from -0.06 to 0.57. Furthermore, 57 1-Mb regions were identified that were associated with at least one fatty acid with a posterior probability of inclusion greater than 0.90. 1-Mb regions on BTA19, BTA26 and BTA29, which harbored fatty acid synthase, Sterol-CoA desaturase and thyroid hormone responsive candidate genes, respectively, explained a high percentage of genetic variance in more than one fatty acid. It was also observed that the correlation between DGV for different fatty acids at a given 1-Mb window ranged from almost 1 to -1. Conclusions Further investigations are needed to identify the causal variants harbored within the identified 1-Mb windows. For the first time, Angus breeders have a tool whereby they could select for altered fatty acid composition. Furthermore, these reported results could improve our understanding of the biology of fatty acid metabolism and deposition. [ABSTRACT FROM AUTHOR]

Abstract: The response of the immune and stress systems have been assessed in response to a lipopolysaccharide (LPS) challenge, yet the role of metabolism in mediating energy requirements during the acute phase response has not been sufficiently studied. This study tested heat-tolerant (Romosinuano [RO]) and heat-sensitive (Angus [ANG]) Bos taurus breeds at different ambient temperatures (Ta) to determine differential metabolic responses to LPS challenge. Twenty-one heifers (ANG: n = 11, 306 ± 26 kg BW; RO: n = 10, 313 ± 32 kg BW) were housed in stanchions in 4 temperature-controlled chambers. Initially, Ta in all 4 chambers was cycling at thermoneutrality (TN; 18.5°C–23.5°C) for a 1-wk adjustment period, followed by an increase in 2 chambers to cycling heat stress (HS; 24°C–38°C) for 2 wk. Five ANG and 5 RO heifers were housed at TN, whereas 6 ANG and 5 RO heifers were housed at HS. On day 19, heifers were fitted with jugular catheters. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), and blood samples were collected from −2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for glucose, insulin, and NEFA concentrations. In addition, feed intake was measured 3 d before and on the day of the challenge. Feed intake decreased over time (P < 0.001) and was decreased in heifers housed at HS compared with heifers housed at TN (P = 0.013). Glucose concentrations before LPS challenge were greater in RO (P = 0.01) than in ANG heifers and greater in TN-housed heifers (P = 0.02) than in HS heifers. Glucose after LPS challenge initially increased before decreasing below baseline concentrations (P < 0.01) in all heifers. In addition, there was a breed by Ta interaction (P < 0.004), such that HS decreased glucose concentrations in ANG heifers compared with ANG heifers housed at TN (P < 0.001), whereas HS did not affect glucose concentrations after LPS challenge in RO heifers (P = 0.941). Nonesterified fatty acid concentrations before LPS challenge were not affected by breed (P = 0.37) or Ta (P = 0.60). Although NEFA concentration after LPS challenge was unaffected by Ta (P = 0.78), there tended to be a breed by Ta interaction (P = 0.07) such that, when housed at HS, RO heifers had greater serum NEFA concentrations after LPS challenge than ANG heifers (P = 0.009). Insulin concentration before LPS challenge was greater in RO heifers than in ANG heifers (P < 0.01). Insulin after LPS challenge increased (P < 0.01), with RO heifers producing a greater insulin response than ANG heifers (P < 0.01). These data suggest that HS decreases the metabolic response of heat-sensitive ANG heifers in response to LPS challenge, thus providing physiological evidence that may explain differences observed in the acute phase response between heat-sensitive ANG and heat-tolerant RO cattle breeds. [Copyright &y& Elsevier]

Abstract: The difference in the acute phase response of a heat-tolerant and a heat-sensitive Bos taurus breed to a lipopolysaccharide (LPS) challenge when housed at different air temperatures (Ta) was studied. Angus (ANG; heat-sensitive; n = 11; 306 ± 26 kg BW) and Romosinuano (RO; heat-tolerant; n = 10; 313 ± 32 kg BW) heifers were transported from the USDA Agricultural Research Service SubTropical Agricultural Research Station in Florida to the Brody Environmental Chambers at the University of Missouri, Columbia. Heifers were housed in stanchions in 4 temperature-controlled environmental chambers. Initially, Ta in the 4 chambers was cycling at thermoneutrality (TN; 18.5°C–23.5°C) for a 1-wk adjustment period, followed by an increase in 2 of the 4 chambers to cycling heat stress (HS; 24°C–38°C) for 2 wk. On day 19, heifers were fitted with jugular catheters and rectal temperature (RT) recording devices. On day 20, heifers were challenged with LPS (0.5 μg/kg BW; 0 h), sickness behavior scores (SBSs) were recorded, and blood samples were collected at 0.5-h intervals from −2 to 8 h and again at 24 h relative to LPS challenge at 0 h. Serum was isolated and stored at −80°C until analyzed for cortisol and cytokine concentrations. A breed by Ta interaction (P < 0.001) was observed for RT such that the post-LPS average RT in RO heifers housed at TN was lower than the RT of all other treatment groups (P < 0.001), whereas ANG heifers housed at HS had greater post-LPS average RT than all other treatment groups (P < 0.001). In response to LPS, HS increased SBS after LPS in RO heifers compared to RO heifers housed at TN (P < 0.001), whereas HS decreased SBS after LPS in ANG heifers compared to ANG heifers housed at TN (P = 0.014). The cortisol response to LPS was greater in TN than in HS heifers (P < 0.01) and was also greater in RO than in ANG heifers (P = 0.03). A breed by Ta interaction (P < 0.01) was observed for tumor necrosis factor-α (TNF-α) concentration such that HS increased post-LPS serum concentrations of TNF-α in ANG heifers compared to ANG heifers housed at TN (P = 0.041), whereas HS decreased post-LPS concentrations of TNF-α in RO heifers compared to RO heifers housed at TN (P = 0.008). A tendency (P < 0.06) was observed for a breed by Ta interaction for IL-6 concentrations such that RO heifers had greater post-LPS concentrations of IL-6 than ANG heifers when housed at HS (P = 0.020). A breed by Ta interaction was observed for interferon-γ (IFN-γ; P < 0.01) concentrations such that HS decreased post-LPS concentrations of IFN-γ in ANG heifers compared to ANG heifers housed at TN (P < 0.001), and HS increased post-LPS concentrations of IFN-γ in RO heifers compared to RO heifers housed at TN (P = 0.017). These data indicate differences in the acute phase response between the heat-tolerant RO and heat-sensitive ANG heifers under different Ta which may aid in elucidating differences in productivity, disease resistance, and longevity among cattle breeds. [Copyright &y& Elsevier]

This case is intended for use by undergraduate students studying agricultural economics, agribusiness, animal science, or food science. Junior level class standing, or higher, would be beneficial. The learning outcomes sought from this case are for students to: (1) distinguish between a commodity marketing system versus a vertically integrated brand; (2) understand the first-mover advantages that have been realized by CAB; and (3) understand the problem of Angus confusion and then explore its possible solutions. A teaching note associated with this case expands upon the above. The note incorporates an excel-formatted data set. With this information, the case can be customized by the professor for use as an exercise; therefore making the case suitable for use in a quantitative analysis class in agricultural economics. [ABSTRACT FROM AUTHOR]

Intramuscular fat and collagen content are major factors affecting beef quality, but mechanisms regulating intramuscular adipose and connective tissue deposition are far from clear. Japanese Wagyu cattle are well known for their extremely high marbling. The objective of this study was to evaluate intramuscular fat (IMF) and collagen deposition in the muscle of Wagyu compared with Angus cattle. Animals were managed under the same condition and slaughtered at an averaging 585 ± 12.1 kg of BW. Samples of sternomandibularis muscle were collected from Wagyu (n = 3) and Angus (n = 3) for molecular and histological investigations of adipogenesis and fibrogenesis. With exception ofC/EBPβ (P = 0.2864) the expression of the adipogenic markers C/EBPα (P = 0.008), PPARγ (P = 0.028), and zip finger protein 423 (Zfp423; P = 0.047) in Wagyu were greater than in Angus muscle, which was consistent with greater IMF depositionin Wagyu (P < 0.05). In addition, more adipocytes and e preadipocytes were detected intramuscularly in Wagyu cattle. Similarly, fibrogenesis was also enhanced in e Wagyu, with a greater expression of fibroblast growth tfactor (FGF)-2 (P = 0.028), FGF receptor 1 (P = 0.030),transforming growth factor (TGF)-β (P = 0.028), collagen I (P = 0.012), and collagen III (P = 0.025). Similarly, Wagyu muscle had greater collagen content (P = 0.002) and decreased collagen solubility (P = 0.005). In addition, muscle fiber diameter was larger (P < 0.0001) in Wagyu s than in Angus cattle. These results clearly show that both IMF and collagen contents are enhanced in Wagyu cattle and more adipogenic cells are detected in Wagyu muscle, indicating intramuscular adipogenesis is enhanced in Wagyu compared with Angus muscle. [ABSTRACT FROM AUTHOR]

Abstract: The objectives of this study were to characterize rectal temperature and coat score under subtropical North American summer conditions for straightbred and crossbred Romosinuano, Brahman, and Angus cattle, to estimate heterosis and breed direct and maternal effects in a subset of those, and to estimate heritability and genetic correlation of these traits. Records of cows (n=612 cows; 1861 total records) and calves (n=1588) from summer days in subtropical Florida, USA, were evaluated using animal models. Records of cows and calves from 2 management groups were analyzed separately. In the first management group, cows were all straightbred as were their calves; most of these cows were dams of cows in the other management group. Cows in that second management group were produced from all possible matings of Romosinuano, Brahman, and Angus bulls and cows; breed groups were 3 straightbred groups and 3 groups of F1 cows (reciprocal crosses combined). Calves of these cows were 3-breed crosses (all F1 cows were mated to bulls of the 3rd breed) and F1 crosses (straightbred cows were bred in approximately equal numbers to bulls of the other 2 breeds). Angus straightbred and crossbred cows and calves had the highest rectal temperature and coat score (subjective score where larger numbers indicated greater quantity of hair on the coat) means in all 4 analyses. In the second management group (straightbred and crossbred cows raising crossbred calves), Romosinuano straightbreds and F1 Romosinuano–Brahman cows had the lowest (P<0.001) rectal temperature and coat score means. Heterosis for rectal temperature was −0.2±0.05 and −0.24±0.05°C for Romosinuano–Angus and Brahman–Angus, respectively (P<0.001). Heterosis for coat score was −1.4±0.2, −0.9±0.2, and −2±0.2 for Brahman–Angus, Romosinuano–Brahman, and Romosinuano–Angus, respectively (P<0.001). Direct effects of Romosinuano and Brahman reduced rectal temperature and coat score; direct effects of Angus increased both. Estimates of heritability were 0.19±0.03 and 0.27±0.04 for rectal temperature and coat score, respectively. Permanent environmental effects as proportions of phenotypic variance were 0.03±0.02 and 0.17±0.04 for rectal temperature and coat score, respectively. The estimate of genetic correlation of these traits was 0.24±0.09. With respect to these traits, Romosinuano may offer benefits of tropical adaptation at least to the extent of Brahman under Florida summer conditions. [Copyright &y& Elsevier]

Abstract: This study evaluated the resistance of cattle of different genetic groups to the tick Rhipicephalus microplus and the relationship with traits of the animals’ hair and coat. Cows of the Senepol×Nelore (SN), Angus×Nelore (AN) and Nelore (NX) genetic groups were submitted to four consecutive artificial infestations, at 14-day intervals, each one with approximately 20,000 tick larvae placed on the animals’ lumbar region. From the 19th to 23rd day of each infestation five counts of the number of ticks were performed on each animal''s left body side. The tick count data (TTC) were transformed into log10 (n +1), and also into percentage of return (PR), where n is the total number of ticks counted at each infestation. Hair samples were collected 24h after the last infestation with flat-nosed pliers. Measures of the average hair length (HL), coat thickness (CT), number of hairs per cm2 (NHCM2) and weight of the samples (SW) were obtained. Pearson''s correlation coefficients were calculated within genetic group to measure association between PR and the hair and coat data. There was a significant difference among genetic groups for the number of ticks, with the AN group having higher counts than the SN and NX groups. For the hair and coat traits, the NX and SN groups had lower values of HL and SW than did the AN group. The SN genetic group had lower NHCM2 counts than the NX and AN groups. There were positive correlations between TTC and CT (P <0.05) and SW (P <0.05) in the SN group. No significant correlation was found for the AN genetic group (P >0.05). [Copyright &y& Elsevier]

Abstract: Carcass and meat quality traits of thirty-six feedlot beef heifers from different genetic groups (GG) fed at two concentrate levels (CL) were evaluated using 12 - Nellore (NE), 12 - ½Angus x ½Nellore (AN) and 12 - ½Simmental x ½Nellore (SN) animals. Six heifers of each GG were randomly assigned into one of two treatments: concentrate at 0.8% or 1.2% of body weight (BW). Heifers fed concentrate at 0.8% of BW had greater (P<0.05) dressing percentage. None of the proximate analysis components of the beef were affected (P>0.05) by either CL or GG. Heifers from the AN group had higher (P<0.05) carcass weights, 12th rib fat thickness and lower dressing percentage (P<0.05) compared to the other groups. NE heifers had greater WBSF values (P<0.05) than the other genetic groups. Data suggest that the concentrate level can be reduced without compromising meat quality traits. [Copyright &y& Elsevier]

Abstract: Previously, it was reported that chronic intra-uterine infusion of PGE1 or PGE2 every 4h inhibited luteolysis in ewes by altering luteal mRNA for luteinizing hormone (LH) receptors and unoccupied and occupied luteal LH receptors. However, estradiol-17β or PGE2 given intra-uterine every 8h did not inhibit luteolysis in cows, but infusion of estradiol+PGE2 inhibited luteolysis. In contrast, intra-luteal implants containing PGE1 or PGE2 in Angus or Brahman cows also inhibited the decline in circulating progesterone, mRNA for LH receptors, and loss of unoccupied and occupied receptors for LH to prevent luteolysis. The objective of this experiment was to determine how intra-luteal implants of PGE1 or PGE2 alter mRNA for prostanoid receptors and how this could influence luteolysis in Brahman or Angus cows. On day-13 Angus cows received no intra-luteal implant and corpora lutea were retrieved or Angus and Brahman cows received intra-luteal silastic implants containing Vehicle, PGE1, or PGE2 and corpora lutea were retrieved on day-19. Corpora lutea slices were analyzed for mRNA for prostanoid receptors (FP, EP1, EP2, EP3 (A–D), EP3A, EP3B, EP3C, EP3D, and EP4) by RT-PCR. Day-13 Angus cow luteal tissue served as pre-luteolytic controls. mRNA for FP receptors decreased in day-19 Vehicle controls compared to day-13 Vehicle controls regardless of breed. PGE1 and PGE2 up-regulated FP gene expression on day-19 compared to day-19 Vehicle controls regardless of breed. EP1 mRNA was not altered by any treatment. PGE1 and PGE2 down-regulated EP2 and EP4 mRNA compared to day-19 Vehicle controls regardless of breed. PGE1 or PGE2 up-regulated mRNA EP3B receptor subtype compared to day-19 Vehicle control cows regardless of breed. The similarities in relative gene expression profiles induced by PGE1 and PGE2 support their agonistic effects. We conclude that both PGE1 and PGE2 may prevent luteolysis by altering expression of mRNA for prostanoid receptors, which is correlated with changes in luteal mRNA for LH receptors reported previously in these same cows to prevent luteolysis. [Copyright &y& Elsevier]

Abstract: Our primary objective of this experiment was to evaluate potential genetic differences between two diverse Bos taurus breeds [Angus (AG) and Romosinuano (RO)] in response to an endotoxin challenge. Eighteen steers (n = 9 steers/breed; 299.4 ± 5.2 kg BW) were acclimated to environmentally controlled chambers maintained at thermoneutrality (19.7 °C) and then fitted with indwelling jugular catheters and rectal temperature (RT) recording devices 1 d before the endotoxin challenge. The next day, blood samples were collected at 30-min intervals from −2 to 8 h, and RT was measured continuously at 1-min intervals throughout the study. At time 0, all steers received an intravenous bolus injection of lipopolysaccharide (LPS; 2.5 μg/kg BW). Serum samples were stored at −80 °C until analyzed for cortisol, proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, and interferon gamma (IFN-γ)], and acute phase proteins (serum amyloid A, acid soluble protein, ceruloplasmin, and α-acid glycoprotein). Rectal temperatures increased in both breeds within 1 h after LPS, with RO producing a greater increase in RT than AG steers (P < 0.001). Serum cortisol and TNF-α increased (P < 0.01) in both breeds within 1 h after the LPS challenge. For cortisol, an overall breed effect (P < 0.02) was detected, such that AG steers had a higher cortisol response than RO steers. A breed × time interaction (P < 0.01) was observed for TNF-α, such that the response was delayed and extended in the RO steers compared with the AG steers. At 2 and 2.5 h after LPS, TNF-α concentrations were greater (P < 0.03) in RO steers than in AG steers. For IL-1β, a breed × time interaction (P < 0.04) was also observed. At 3 h after LPS, IL-1β concentrations were greater (P < 0.01) in RO steers than in AG steers. Serum IL-6 and IFN-γ increased (P < 0.01) in a similar manner in both groups after the LPS challenge. These data show differences in the innate immune response between two diverse Bos taurus breeds which may provide insight about differences observed in productivity, heat tolerance, disease resistance, and longevity among cattle breeds. [Copyright &y& Elsevier]

Abstract: Previously, it was reported that chronic intra-uterine infusion of PGE1 or PGE2 every four hours inhibited luteolysis in ewes. However, estradiol-17β or PGE2 given intra-uterine every 8h did not inhibit luteolysis in heifers, but infusion of estradiol+PGE2 inhibited luteolysis in heifers. The objective of this experiment was to determine whether and how intra-luteal implants containing PGE1 or PGE2 prevent luteolysis in Angus or Brahman cows. On day-13 post-estrus, Angus cows received no intra-luteal implant and corpora lutea were retrieved or Angus and Brahman cows received intra-luteal silastic implants containing Vehicle, PGE1, or PGE2 and corpora lutea were retrieved on day-19. Coccygeal blood was collected daily for analysis for progesterone. Breed did not influence the effect of PGE1 or PGE2 on luteal mRNA for LH receptors or unoccupied or occupied luteal LH receptors did not differ (P >0.05) so the data were pooled. Luteal weights of Vehicle-treated Angus or Brahman cows from days-13–19 were lower (P <0.05) than those treated with intra-luteal implants containing PGE1 or PGE2. Day-13 Angus luteal weights were heavier (P <0.05) than Vehicle-treated Angus cows on day-19 and luteal weights of day-13 corpora lutea were similar (P >0.05) to Angus cows on day-19 treated with intra-luteal implants containing PGE1 or PGE2. Profiles of circulating progesterone in Angus or Brahman cows treated with intra-luteal implants containing PGE1 or PGE2 differed (P <0.05) from controls, but profiles of progesterone did not differ (P >0.05) between breeds or between cows treated with intra-luteal implants containing PGE1 or PGE2. Intra-luteal implants containing PGE1 or PGE2 prevented (P <0.05) loss of luteal mRNA for LH receptors and unoccupied or occupied receptors for LH compared to controls. It is concluded that PGE1 or PGE2 alone delays luteolysis regardless of breed. We also conclude that either PGE1 or PGE2 prevented luteolysis in cows by up-regulating expression of mRNA for LH receptors and by preventing loss of unoccupied and occupied LH receptors in luteal tissue. [Copyright &y& Elsevier]

The objective of this study was to compare performance and aspects of adaptability attributes of cattle from a Florida Angus bloodline (local source from a mostly closed herd for over 50 yr) to cattle that are representative of modern Angus bloodlines (outside source) in US subtropical conditions. Embryos from both sources were transferred to Brahman-crossbred cows in South Florida, and calves (n = 82) were born in 3 yr. Before weaning, summer tympanic temperatures were recorded hourly for 3 d in each year. Heifers were placed with fertile bulls until diagnosed pregnant. Traits relative to sexual maturation of bulls were recorded at 1- or 2-mo intervals until approximately 17 mo of age. Calves from outside sources had greater hip height at weaning than calves from the local source (P < 0.001; 108.8 ± 0.62 and 104.7 ± 0.68 cm, respectively). Local-source calves (n = 37) had greater (P = 0.03) exit velocity (2.7 ± 0.3 m/s) than outside-source (n = 45) calves (2.0 ± 0.29 m/s), which may be indicative of more nervous or temperamental disposition. However, no source differences were detected for other assessments of disposition (chute or pen score, P > 0.8). Few source differences for minimum, maximum, or range of daily tympanic (inner ear) temperatures were detected. At 17 mo of age, outside-source heifers were heavier (P = 0.05) and had greater (P < 0.001) hip height than Angus heifers from the local source. Heifers from the outside source were younger (P < 0.001) at the time of their first conception (454 ± 17.5 d) than heifers from the local source (550 ± 16.9 d). Outside-source heifers also had greater (P < 0.02) pregnancy and calving rates (0.7 ± 0.119 and 0.62 ± 0.125, respectively) from exposure to bulls within a year from weaning than the heifers from the local source (0.29 ± 0.089 and 0.19 ± 0.077, respectively). Bulls from the outside source were heavier (P = 0.05) at 320 d of age than local-source bulls. From 14 through 17 mo of age, outside-source bulls had greater (P ⩽ 0.05) scrotal circumference and tended (P ⩽ 0.15) to be heavier than local-source bulls. There appeared to be no performance or adaptation advantages for the local-source Angus through 17 mo of age. The large source difference for age at first conception in heifers merits additional attention and comparison with cow lifetime production performance for the 2 sources. [ABSTRACT FROM AUTHOR]

ETH10 is a dinucleotide microsatellite within the promoter of signal transducer and activator of transcription 6 (STAT6) gene on bovine chromosome 5. ETH10 is included in the panel of genetic markers used in parentage testing procedures of cattle breed associations. Allelic sizes of ETH10 PCR amplicons range from 199 to 225 bp. Objectives of this study were to use microsatellite data from beef cattle breed associations to investigate genetic distance and population stratification among Angus- and Brahman-influenced cattle and to use ETH10 genotypes and growth and ultrasound carcass data to investigate their statistical relationships. Three series of genotype to phenotype association analyses were conducted with 1) Angus data (n = 5,094), 2) Brangus data (3/8 Brahman × 5/8 Angus; n = 2,296), and 3) multibreed data (n = 4,426) of Angus and Brangus cattle. Thirteen alleles and 38 genotypes were observed, but frequencies varied among breed groups. Tests of genetic identity and distance among 6 breed composition groups increasing in Brahman influence from 0 to 75% revealed that as Brahman-influence increased to ⩾50%, genetic distance from Angus ranged from 18.3 to 43.5%. This was accomplished with 10 microsatellite loci. A mixed effects model involving genotype as a fixed effect and sire as a random source of variation suggested that Angus cattle with the 217/219 genotype tended to have 2.1% heavier (P = 0.07) 205-d BW than other genotypes. In Brangus cattle, allele combinations were classified as small (⩽215 bp) or large (⩾217 bp). Brangus cattle with the small/large genotype had 2.0% heavier (P < 0.05) birth weight, yet cattle with the large/large genotype had approximately 5.1% greater (P < 0.05) percentage of fat within LM and more LM per BW than cattle with small/large or small/small genotypes. Genotype-to-phenotype relationships were not detected in multibreed analyses. The ETH10 locus appears to be associated with growth and carcass traits in Angus and Brangus cattle. Results from this study provide support for STAT6 as one of the candidate genes underlying cattle growth QTL on chromosome 5. [ABSTRACT FROM AUTHOR]

Molecular markers for beef tenderness are classic examples of the contribution of genome technology to animal breeding through marker-assisted selection (MAS). Markers on the μ-calpain (CAPN1) and calpastatin (CAST) genes have been extensively evaluated for their association with tenderness. However, little is known about their potential effect on other economically important traits. In this work, the association of molecular markers for beef tenderness with growth traits was evaluated in Angus cattle of Argentina. Expected progeny differences were extracted from the 2008 Angus Sire Summary of Argentina. Information corresponding to 268 influential bulls that had been genotyped for two markers in CAPN1 and two markers in CAST was provided by the Argentine Angus Association. Genotype probabilities were assigned, by segregation analysis, to those bulls in the Sire Summary that had no marker information. Expected progeny differences of 1365 sires were regressed on the number of alleles favouring tenderness at each locus. There was a significant effect of markers on expected progeny differences of birth weight, weaning weight (direct), weight at 18 months and rib eye area. In general, there was a negative effect of alleles favouring tenderness on growth traits. These correlated responses should be taken into account when molecular markers are used in selection schemes that aim to improve beef tenderness. [ABSTRACT FROM AUTHOR]

Herbage intake was measured using n-alkanes (at age 10 and 13 months) and the pre- and post-grazing technique (at age 12 and 14 months) in 80 Angus heifers selected for high (Hi-Gr) or low (Lo-Gr) growth rate or high (Hi-Milk) or low (Lo-Milk) milk production. Average liveweight and estimated herbage intake at 10 months were 240.2±0.4 kg and 3.47±0.1 kg dry matter (DM)/head per day respectively. The respective values at 13 months of age were 287.2±1.9 kg and 6.50±0.36 kg DM/head per day. No differences in estimated herbage intake among the genetic lines were detected using n-alkanes at 10 or 13 months of age. Average liveweight at 12 months of age was 247.1±0.7 kg and mean estimated intakes were 4.86±0.26, 4.17±0.26, 4.37±0.26 and 3.00±0.26 kg DM/head per day for the Hi-Gr, Lo-Gr, Hi-Milk and Lo-Milk lines, respectively. The Lo-Milk line had lower (P<0.05) estimated intake than the other three lines. At 14 months of age, average liveweight was 272.5±0.6 kg and estimated intakes were 6.99±0.18, 6.52 kg±0.18, 6.71±0.18 and 7.28±0.19 kg DM/head per day for the Hi-Gr, Lo-Gr, Hi-Milk or Lo-Milk lines, respectively. Lo-Milk heifers had higher (P<0.05) intakes than heifers from the Lo-Gr and Hi-Milk lines. No statistical difference in intake between the Lo-Milk and the Hi-Gr lines was detected. In general, the Hi-Gr heifers outperformed the heifers from other lines. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the fatty acid (FA) composition of intramuscular fat from the LM of 3 divergent breeds of cattle: Angus (AN, n = 9), Brahman (BR, n = 7), and Romosinuano (RM, n = 11). Cattle were blocked by breed and finished 129 d before slaughter in one year and 157 d in the next year. Longissimus muscle samples were collected from each carcass between the 10th and 13th ribs, trimmed of external fat, frozen in liquid nitrogen, homogenized, and used for fat extraction, using a modified Folch procedure. Extracted fat was analyzed for FA by using a GLC system with an HP-88 capillary column. Fatty acid composition was expressed using both a normalized percentage (%) and gravimetric calculation (mg/g of fresh muscle tissue) in relation to degree of saturation, which was determined using a saturation index (ratio of total SFA to total unsaturated FA). Crude fat determination revealed that LM from AN purebred cattle had the greatest amount of intramuscular fat (7.08%; P = 0.001). Although intramuscular fat of LM from RM contained a reduced percentage of total SFA (P = 0.002) compared with AN, it had the greatest percentage of total PUFA (P < 0.001 and P = 0.020). The percentages of total MUFA were similar among the 3 breeds (P = 0.675). The gravimetric calculation, a measure of actual FA concentration, showed significantly greater concentrations of SFA (26.67 mg/g), MUFA (26.50 mg/g), and PUFA (2.37 mg/g) in LM from AN cattle, as compared with LM from BR and RM cattle (P < 0.001). Interestingly, BR purebreds had the least PUFA concentration (1.49 mg/g; P < 0.001) in the LM, although their intramuscular fat content was similar to that of RM (P = 0.924). Regardless of breed, the MUFA proportion was always the greatest (47.58%; P ⩽ 0.005), whereas PUFA was the least contributor to FA composition (1.49 to 2.37 mg/g and 4.36 to 8.78%; P < 0.001). Beef LM fatty acid composition was characterized by palmitic and oleic acids being the most abundant FA (P < 0.001). These results suggested a genetic variation in FA synthesis and deposition among breeds that influenced both marbling and its composition. [ABSTRACT FROM AUTHOR]

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). Angussired 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. 591.3 ± 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. [ABSTRACT FROM AUTHOR]