Search

The article evaluates the efficacy of a random regression model (RRM) genetic prediction for heifer first-service conception rate (FSCR). The resulting expected progeny differences (EPD) to those obtained using a traditional animal threshold model (ATM) are compared. Topics discussed include heifer pregnancy in Red Angus cattle, artificial insemination, and FSCR at different ages of insemination.

The purposes of this study were to determine if the successful treatment of bovine respiratory disease (BRD) in suckling calves was associated with a long-term increase in mean pulmonary arterial pressure (mPAP) and, to screen for associations between blood leukogram variables and mPAP. A cohort of Red Angus calves (n = 74) were followed from birth to weaning at an altitude of 975 m. Calves were weaned at 172 ± 14 d when their mPAP was measured and whole blood collected. Thirty calves that had been treated for BRD (34 to 45 d prior) and 30 calves that had not required treatment for BRD were sampled. Treatment for BRD had no effect on mPAP (P = 0.37). Mean mPAP was 48 ± 8 mm Hg (± SD) with a minimum of 34 mm Hg and a maximum at 69 mm Hg. Weaning weight and sex tended to be associated with mPAP, but they explained just 5% of the variation in mPAP (P = 0.08; Adj. r² = 0.05). Fibrinogen (P = 0.008) and absolute lymphocyte count (P = 0.06) were negatively associated with mPAP, whereas absolute monocyte count was positively associated with mPAP (P = 0.01). The findings of this study suggest that pre-weaning treatment for BRD does not increase a calves' post-weaning risk of congestive right heart failure. Further, components of the immune and acute phase response system may play a role in the development and progression of pulmonary hypertension. [ABSTRACT FROM AUTHOR]

Reproductive performance is the most important component of cattle production from the standpoint of economic sustainability of commercial beef enterprises. Heifer Pregnancy (HPG) and Stayability (STAY) genetic predictions are 2 selection tools published by the Red Angus Association of America (RAAA) to assist with improvements in reproductive performance. Given the importance of HPG and STAY to the profitability of commercial beef enterprises, the objective of this study was to identify QTL associated with both HPG and STAY in Red Angus cattle. A genome-wide association study (GWAS) was performed using deregressed HPG and STAY EBV, calculated using a single-trait animal model and a 3-generation pedigree with data from the Spring 2015 RAAA National Cattle Evaluation. Each individual animal possessed 74,659 SNP genotypes. Individual animals with a deregressed EBV reliability > 0.05 were merged with the genotype file and marker quality control was performed. Criteria for sifting genotypes consisted of removing those markers where any of the following were found: average call rate less than 0.85, minor allele frequency < 0.01, lack of Hardy-Weinberg equilibrium (P < 0.0001), or extreme linkage disequilibrium (r² > 0.99). These criteria resulted in 2,664 animals with 62,807 SNP available for GWAS. Association studies were performed using a Bayes Cn model in the BOLT software package. Marker significance was calculated as the posterior probability of inclusion (PPI), or the number of instances a specific marker was sampled divided by the total number of samples retained from the Markov chain Monte Carlo chains. Nine markers, with a PPI ≥ 3% were identified as QTL associated with HPG on BTA 1, 11, 13, 23, and 29. Twelve markers, with a PPI ≥ 75% were identified as QTL associated with STAY on BTA 6, 8, 9, 12, 15, 18, 22, and 23. [ABSTRACT FROM AUTHOR]

Accuracy of sire selection is limited by how well animals are characterized for their environment. The objective of this study was to evaluate the presence of genotype × environment interactions (G×E) for birth weight (BiW) and weaning weight (WW) for Red Angus in the United States. Adjusted weights were provided by the Red Angus Association of America. Environments were defined as 9 regions within the continental United States with similar temperature-humidity indices. Mean weights of calves were determined for each region and for each sire's progeny within each region. A reaction norm (RN) for each bull was estimated by regressing the sire means on the region means weighted for the number of progeny of each sire. The range for BiW and WW RN was -1.3 to 4.0 and -1.7 to 2.8, respectively. The heritabilities of BiW and WW RN were 0.40 and 0.39, respectively. Phenotypic and genetic correlations between BiW and WW RN were 0.19 and 0.54, respectively. The phenotypic correlation of the progeny mean to the RN was -0.20 (P <0.05) and suggests that sires with higher means are more stable in progeny performance across environments. Weights in different regions were considered separate traits and genetic correlations were estimated between all pairs of regions as another method to determine G×E. Genetic correlations < 0.80 indicate G×E at a level for concern, but existed for only 2 of 36 estimates for BiW and 12 of 36 estimates for WW. Genetic correlations between different regions ranged from 0.74 to 0.96 for BiW and 0.62 to 0.99 for WW and indicate that sires tend to rank similarly across environments for these traits. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A total of 1379 beef bull pictures were surveyed to determine visibility of feet and legs from four American semen company websites. Five different breeds were represented: Angus, Red Angus, Hereford (polled and horned), Simmental, and Charolais. In addition to visibility, data on other variables were collected to establish frequencies and correlations. These included breed, color, material that obscured visibility, such as grass, picture taken at livestock show or outside, semen company, photographer, video, and age of bull. A foot and leg visibility score was given to each bull picture. Only 19.4% of the pictures had fully visible feet and legs. Both the hooves and dewclaws were hidden on 32.5% of the pictures. Correlation between bull's birthdate and the first four visibility scores was statistically significant (P < 0.0001). As age increased the feet and legs were more likely to be visible in the bull's picture. This may possibly be due to greater availability of both photo editing software and digital photography. One positive finding was that 6% of the bulls had a video of the bull walking which completely showed his feet and legs. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of alternative-measurements of body weight and DMI used to evaluate residual feed intake (RFI). Weaning weight (WW), ADG, and DMI were recorded on 970 growing purebred Charolais bulls (n = 519) and heifers (n = 451) and 153 Red Angus growing steers (n = 69) and heifers (n = 84) using a GrowSafe (GrowSafe, Airdrie, Alberta, Canada) system. Averages of individual DMI were calculated in 10-d increments and compared to the overall DMI to identify the magnitude of the errors associated with measuring DMI. These incremental measurements were also used in calculation of RFI, computed from the linear regression of DMI on ADG and midtest body weight0.75 (MMWT). RFI_ Regress was calculated using ADG_Regress (ADG calculated as the response of BW gain and DOF) and MMWT_PWG (metabolic midweight calculated throughout the postweaning gain test), considered the control in Red Angus. A similar calculation served as control for Charolais; RFI was calculated using 2-d consecutive start and finish weights (RFI_ Calc). The RFI weaning weight (RFI_WW) was calculated using ADG_WW (ADG from weaning till the final out weight of the postweaning gain test) and MMWT_WW, calculated similarly. Overall average estimated DMI was highly correlated to the measurements derived over shorter periods, with 10 d being the least correlated and 60 d being the most correlated. The ADG_Calc (calculated using 2-d consecutive start and finish weight/DOF) and ADG_WW were highly correlated in Charolais. The ADG_Regress and ADG_Calc were highly correlated, and ADG_Regress and ADG_WW were moderately correlated in Red Angus. The control measures of RFI were highly correlated with the RFI_WW in Charolais and Red Angus. The outcomes of including abbreviated period DMI in the model with the weaning weight gain measurements showed that the model using 10 d of intake (RFI WW_10) was the least correlated with the control measures. The model with 60 d of intake had the largest correlation with the control measures. The fewest measured intake days coupled with the weaning weight values providing acceptable predictive value was RFI_WW_40, being highly correlated with the control measures. As established in the literature, at least 70 d is required to accurately measure ADG. However, we conclude that a shorter period, possibly as few as 40 d is needed to accurately estimate DMI for a reliable calculation of RFI. [ABSTRACT FROM AUTHOR]

Copyright of Taurus is the property of Revista Taurus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a case study of a six-year-old Red Angus cow that was presented to a clinic due to difficulty in eating after going to a mandibular fracture repair due to motor vehicle accident. The cow has underwent a mandibular condylectomy and imaging shows a temporomandibular luxation. It mentions that the cow improves his mastication after mandibular condylectomy but was being euthanized due to infection.

This study assessed milk yield and composition of Angus and Angus-cross beef cows raised in southern Brazil. A total of 128 records were collected in 2 consecutive calving seasons from cows between 3 and 5 yr of age of 4 breed compositions: Angus (ANAN), Caracú x Angus (CRAN), Hereford x Angus (HHAN), and Nelore x Angus (NEAN). These cows were mated to Brangus (BN) or Braford (BO) bulls and managed under extensive grazing conditions in southern Brazil. Milk production of these cows was assessed by 2 procedures: indirectly by the calf weigh-suckle-weigh procedure (WD) and directly by machine milking (MM). Lactation curves were estimated using nonlinear regression and the following related traits were derived: peak yield (PY), peak week (PW), total yield at 210 d (TY210), and lactation persistence (PERS). Milk composition and calf weaning weight adjusted to 210 d (WW210) were also determined. The MM technique was considered more accurate because of lower standard errors of estimated means, greater statistical power, and greater correlation between TY210 and WW210 (0.50) compared to WD (0.36). Considering the more precise evaluation by MM, the CRAN and NEAN cows had greater TY210(1070 and 1116 kg, respectively) and PY (8.1 and 7.8 kg, respectively) compared to ANAN and HHAN cows, which had 858 and 842 kg for TY210 and 6.6 and 6.3 kg for PY, respectively. The NEAN cows had the latest PW at 10.8 wk. Late-calving cows had 21% lower TY210 compared to cows that calved earlier. Milk composition was influenced by cow genotype, with CRAN and NEAN cows producing milk with greater fat (3.8 and 3.9%, respectively) and protein (3.2 and 3.1%, respectively) content compared to ANAN and HHAN cows. Regardless of the genotype, fat, protein, and total solids increased in concentration from beginning to end of lactation, while lactose content decreased. Crossbreeding of Angus with adapted breeds of taurine or indicine origin can be effective in increasing milk yield and nutrient content and, consequently, producing heavier calves at weaning under extensive grazing in southern Brazil and other similar subtropical climate regions. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Veterinary Science is the property of Archives of Veterinary Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Investigating the genetic and physiological drivers of postweaning residual feed intake (RFI) and finishing phase feed efficiency (FE) may identify underlying mechanisms that are responsible for the variation in these complex FE traits. The objectives were 1) to evaluate the relationship of serum IGF-I concentration and muscle gene expression with postweaning RFI and sire maintenance energy (MEM) EPD and 2) to determine fiber type composition as it relates to postweaning RFI and finishing phase FE. Results indicate that RFI and serum IGF-I con-centration were not associated (P > 0.05); however, negative correlations (P < 0.05) between sire MEM EPD and serum IGF-I concentration were observed. Gene expression differences between high- and low-RFI animals were observed in cohort 1, where IGFBP5 expression was greater (P < 0.05) in high-RFI animals. When animals were grouped according to sire MEM EPD, the low MEM EPD group of cohort 1 showed greater muscle mRNA expression (P <0.01) offatty acid synthase (FASN) and marginally (P < 0.10) greater expression of IGFBP5 and C/EBP alpha (C/EBPa) whereas the high MEm EPD group of cohort 2 had greater muscle mRNA expression of IGFBP2 (P < 0.05) and C/EBPa (P < 0.01) and marginally (P <0.10) greater expression of IGFBP3. Biopsy tissue samples collected at harvest revealed that the per-centage of type Ha fibers was lower (P < 0.05) in high-RFI steers, with a similar trend (P < 0.10) being observed in high finishing phase FE steers. The percentage of type IIb fibers was higher (P < 0.05) in high-RFI (and finishing phase FE) steers than in low-RFI (and finishing phase FE) steers. There was a marginal, negative correlation between RFI and type I (r = -0.36, P = 0.08) and IIa (r = -0.37, P = 0.07) fiber percentages and a positive correlation (r = 0.48, P = 0.01) between RFI and type lib fiber percentage whereas finishing phase FE was negatively correlated (r = -0.43, P = 0.03) with type I fiber percentage and positively correlated (r = 0.44, P = 0.03) with type lib fiber percentage. Therefore, our data indicate that 1) serum IGF-I (collected at weaning) is not an indicator of postweaning RFI, 2) the GH-IGF axis appears to have some involvement with RFI at the molecular level; however, muscle gene expression results were not consistent across cohorts, and 3) low-RFI animals may have the ability to more efficiently maintain and accrete muscle mass due to their fiber type composition, specifically a greater proportion of type I fibers. [ABSTRACT FROM AUTHOR]

Energy expenditure is a physiological process that may be closely associated with residual feed intake (RFI). The maintenance energy (MEM) EPD was developed by the Red Angus Association of America (RAAA) and is used as an indicator of energy expenditure. The objectives of this study were to evaluate and quantify the following relationships using progeny of Red Angus (RA) sires divergent for MEM EPD: 1) postweaning RFI and finishing phase feed efficiency (FE), 2) postweaning RFI and end-product quality, and 3) postweaning RFI and sire MEM EPD. A total of 12 RA sires divergent for MEM EPD were chosen using the RAAA-generated MEM EPD values and were partitioned into 2 groups: high MEM EPD (≥4 Mcal/mo) and low MEM EPD (<4 Mcal/mo), based on the breed average of 4 Mcal/mo. Commercial crossbred cows were inseminated to produce 3 cohorts of progeny, which were tested for postweaning RFI (cohorts 1, 2, and 3) and finishing phase FE (cohorts 1 and 3). Results indicate that postweaning RFI and finishing phase FE of steer progeny tended to be positively correlated (r = 0.38; P = 0.06) in cohort 1 and were positively correlated (r = 0.50; P = 0.001) in cohort 3. In addition, postweaning RFI was not phenotypically correlated (P > 0.05) with any carcass traits or end-product quality measurements. Sire MEM EPD was phenotypically correlated (P < 0.05) with carcass traits in cohort 1 (HCW, LM area, KPH, fat thickness, and yield grade) and cohort 2 (KPH and fat thickness). Since variation in measured LM area was not explained by the genetic potential of rib eye area EPD, and therefore, the observed correlation between sire MEM EPD and measured LM area may suggest an association between MEM EPD and LM area. A correlation (r = 0.24; P = 0.02) was observed between postweaning RFI and ultrasound intramuscular fat percentage in cohort 2 but was not detected in cohorts 1 or 3. In addition, no phenotypic relationship was observed (P > 0.05) between progeny postweaning RFI and sire MEM EPD. Therefore, results suggest 1) RFI measured during the postweaning growth phase is indicative of FE status in the finishing phase, 2) neither RFI nor sire MEM EPD negatively affected carcass or end-product quality, and 3) RFI and sire MEM EPD are not phenotypically associated. [ABSTRACT FROM AUTHOR]

Copyright of Ciência Animal Brasileira is the property of Universidade Federal de Goias, Escola de Veterinaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Selection criteria for yearling bulls commonly include indicators of fertility and carcass merit, such as scrotal circumference (SC) and intramuscular fat percentage (IMF). Genetic correlation estimates between ultrasound traits such as IMF and carcass marbling score (MS) with fertility traits SC and heifer pregnancy (HP) have not been reported. Therefore, the objective of this study was to estimate the genetic parameters among the indicator traits IMF and SC, and the economically relevant traits MS and HP. Records for IMF (n = 73,051), MS (n = 15,260), SC (n = 43,487), and HP (n = 37,802) were obtained from the Red Angus Association of America, and a 4-generation ancestral pedigree (n = 10,460) was constructed from the 8,915 sires represented in the data. (Co)variance components were estimated using a multivariate sire model and average information REML to obtain estimates of heritability and genetic correlations. Fixed effects included contemporary group and the linear effect of age at measurement for all traits, and an additional effect of age of dam for both HP and SC. The random effect of sire was included to estimate additive genetic effects, which were assumed to be continuous for IMF, MS, and SC, but a probit threshold link function was fitted for HP. Generally moderate heritability estimates of 0.29 ± 0.01, 0.35 ± 0.06, 0.32 ± 0.02, and 0.17 ± 0.01 were obtained for IMF, MS, SC, and HP on the underlying scale, respectively. The confidence interval for the estimated genetic correlation between MS and HP (0.10 ± 0.15) included zero, suggesting a negligible genetic association. The genetic correlation between MS and IMF was high (0.80 ± 0.05), but the estimate for HP and SC (0.05 ± 0.09) was near zero, as were the estimated genetic correlations of SC with MS (0.01 ± 0.08) and IMF (0.05 ± 0.06), and for HP with IMF (0.13 ± 0.09). These results suggest that concomitant selection for increased fertility and carcass merit would not be antagonistic. [ABSTRACT FROM AUTHOR]

The article investigates the variability of scrotal circumferences (SC) and the relationship between testicular weight (TW) and live weight (BW) in different breeds of beef bulls. The study indicated that Devon, Polled Hereford and Red Angus breeds showed higher SC values than the other studied breeds and that increase of SC was proportional to increase in TW. This suggest that SC in young bulls is a useful predictor of TW in adult bulls, therefore a useful tool for bull selection.

To establish the basis for implementation of a producer education program, a social assessment of the willingness and barriers to adoption of a measure of feed efficiency in beef cattle [residual feed intake (RFI)] was conducted. A 35-question mailed survey was sent to 1,888 producers acquired from the stratified random sample of the Idaho Cattle Association member list (n = 488), Red Angus Association of America member list (n 2,208), and Red Angus Association of America bull buyer list (n = 5,325). The adjusted response rate for the survey was 49.9%. Of the survey respondents, 58.7% were commercial cow/calf producers and 41.3% were seedstock producers or operated a combination seedstock/commercial operation. Commercial operations had an average of 223 ± 17 cows and 13 ± 3 bulls, whereas seedstock herds (including combination herds) had slightly fewer cows (206 ± 24) and more bulls (23 ± 6). Both commercial and seedstock operators indicated that calving ease/birth weight was the most important trait used to evaluate genetic merit of breeding bulls. Only 3.8 and 4.8% of commercial and seedstock producers indicated that feed efficiency was the most important characteristic used for bull selection. Binary logistic regression models were used to predict willingness of seedstock producers to begin collecting data for the calculation of RFI on their bulls, or to predict willingness of commercial producers to begin selecting bulls based on RFI data. In response, 49.1% of commercial producers and 43.6% of seedstock producers indicated they were willing to adopt RFI as a measure of feed efficiency. These data indicate that feed efficiency was one of the traits that producers consider important; those who perceive feed efficiency as important tended to be actively involved in data collection on their herds, underpinning the notion that objective assessment was valued and used by some. Additional data collection in a future social assessment will continue to elaborate the proportion of producers who perceive feed efficiency as an increasingly important decision and management tool for beef production. [ABSTRACT FROM AUTHOR]

Longissimus thoracis steaks from steers (n = 464) with 0 to 50% inheritance of Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental were evaluated during 6 d of display to assess genetic contributions to color stability. Color space values [CIE L* (lightness), a* (redness), b* (yellowness)], chroma, color change (ΔE), and surface metmyoglobin (K/S 572/525) were determined on d 0 and 6 of display. Myoglobin concentration was highly heritable (0.85), but ultimate pH was weakly heritable (0.06). Day 0 L* values were moderately heritable (0.24). Variation in metmyoglobin, L*, and ΔE on d 6 was moderately explained by genetic factors (41, 40, and 29%, respectively). Change during display was moderately heritable for a* (0.31), b* (0.23), chroma (0.35), and surface metmyoglobin (0.29). At the start of display, Angus steaks had greater (P < 0.05) L* values than those from all breeds except Charolais. On d 6, Angus steaks had greater (P < 0.05) L* (50.0) values than Gelbvieh, Hereford, and Simmental steaks (46.1, 44.0, and 44.5, respectively). Day 0 values for a*, b*, chroma, and ΔE were not affected by breed (P> 0.05). On d 6, a* values were greater (P < 0.05) for Charolais and Limousin steaks (31.1 and 30.5) than Angus, Hereford, and Red Angus steaks (27.4, 27.7, and 26.3, respectively). Thus, a* changed less (P < 0.05) in Charolais and Limousin steaks (1.8 and 2.6, respectively) vs. steaks from other breeds. Day 6 b* values were greater (P < 0.05) in Charolais (24.5) and Limousin steaks (24.0) vs. Gelbvieh (22.2), Hereford (21.9), and Red Angus steaks (21.4). Thus, b* values changed less (P <0.05) in Charolais and Limousin steaks (1.5 and 1.7, respectively) than in Angus, Gelbvieh, Hereford, and Red Angus steaks (4.3, 3.8, 4.4, and 5.1, respectively). After 6 d of display, Charolais and Limousin steaks had greater chroma (P < 0.05; 39.5 and 38.8, respectively) compared with Angus, Hereford, and Red Angus steaks (35.4, 35.3, and 33.9, respectively). Less (P < 0.05) change in chroma occurred for Charolais and Limousin (2.1 and 2.8, respectively) than in Angus, Gelbvieh, Hereford, and Red Angus steaks (7.1, 6.6, 7.4, and 9.0, respectively). Myoglobin concentration was less for Charolais and Limousin (P < 0.05; 2.77 and 2.72, respectively) compared with Gelbvieh, Red Angus, and Simmental steaks (3.62, 3.43, and 3.71, respectively). Breeds did not differ in pH (P > 0.05). These data suggest Charolais- and Limousin-carcasses produced steaks with greater lean color stability than Angus, Hereford, and Red Angus carcasses. Furthermore, these findings suggest that genetics contribute substantially to animal-to-animal variation in lean color, particularly in maintaining color. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the population structure and genetic diversity of registered American Red Angus cattle. Inbreeding and average relationship coefficients, effective population size, effective number of founders, and effective number of herds supplying grandparents to the popu- lation were calculated from the recorded pedigree. In- breeding in 1960 was 10.7% and decreased until 1974 at a rate of 0.2% per year, whereas in 1975 inbreeding was 3.2% and increased until 2005 at a rate of 0.02% per year. The numerator relationship coefficients of the 10 individual paternal grandsires (PGS; sires of sires), paternal granddams (PGD; dams of sires), maternal grandsires (MCS; sires of dams), and maternal grand- dams (MGD; dams of dams) that had the greatest num- ber of registered grandprogeny, with all other registered animals, increased with their birth year from 1960 on. Average numerator relationships of these with all other PGS, PGD, MGS, MGD, bulls, and sires were greater for paternal (PGS, PGD) than maternal (MGS, MGD) pathways. The effective population size was 445, with 649 effective founders. The effective numbers of herds supplying PGS, PGD, MGS, and MGD were 435, 369, 453, and 459, respectively. Inbreeding is at a low level and the effective population size is large. The effective number of founders and effective number of herds sup- plying grandparents is small in relation to the total number of animals and herds, indicating the dispro- portionate influence of a few founders and herds on the genetics of the breed. The calculated parameters indicate satisfactory genetic diversity in American Red Angus cattle. [ABSTRACT FROM AUTHOR]

Background: Osteopetrosis is a skeletal disorder of humans and animals characterized by the formation of overly dense bones, resulting from a deficiency in the number and/or function of bone-resorbing osteoclast cells. In cattle, osteopetrosis can either be induced during gestation by viral infection of the dam, or inherited as a recessive defect. Genetically affected calves are typically aborted late in gestation, display skull deformities and exhibit a marked reduction of osteoclasts. Although mutations in several genes are associated with osteopetrosis in humans and mice, the genetic basis of the cattle disorder was previously unknown. Results: We have conducted a whole-genome association analysis to identify the mutation responsible for inherited osteopetrosis in Red Angus cattle. Analysis of >54,000 SNP genotypes for each of seven affected calves and nine control animals localized the defective gene to the telomeric end of bovine chromosome 4 (BTA4). Homozygosity analysis refined the interval to a 3.4-Mb region containing the SLC4A2 gene, encoding an anion exchanger protein necessary for proper osteoclast function. Examination of SLC4A2 from normal and affected animals revealed a ~2.8-kb deletion mutation in affected calves that encompasses exon 2 and nearly half of exon 3, predicted to prevent normal protein function. Analysis of RNA from a proven heterozygous individual confirmed the presence of transcripts lacking exons 2 and 3, in addition to normal transcripts. Genotyping of additional animals demonstrated complete concordance of the homozygous deletion genotype with the osteopetrosis phenotype. Histological examination of affected tissues revealed scarce, morphologically abnormal osteoclasts displaying evidence of apoptosis. Conclusions: These results indicate that a deletion mutation within bovine SLC4A2 is associated with osteopetrosis in Red Angus cattle. Loss of SLC4A2 function appears to induce premature cell death, and likely results in cytoplasmic alkalinization of osteoclasts which, in turn, may disrupt acidification of resorption lacunae. [ABSTRACT FROM AUTHOR]

The objectives of the present study were to estimate the allele and genotype frequencies of the POU1F1/HinfI polymorphisms in beef cattle belonging to four different genetic groups and to determine the effects of these polymorphisms on growth traits in cattle. The 451-bp PCR products of POU1F1 gene digested with HinfI exhibited three genotypes and two alleles, which were at Hardy-Weinberg equilibrium (P > 0.05). Genotype BB was the predominant genotype and B the predominant allele in the studied populations. There was significant difference between Limousin × Qinchuan and Qinchuan in the distribution of genotypes (P < 0.0001). The association of the polymorphism of the POU1F1 gene with growth traits among Qinchuan, Limousin × Qinchuan, Angus × Qinchuan and Germany Yellow × Qinchuan crosses was analyzed. Body weight and wither height of individuals with genotypes AB were higher (P < 0.05)than that of individuals with genotype BB in the Germany Yellow × Qinchua cross, but were not in the other three populations (P > 0.05). [ABSTRACT FROM AUTHOR]

The article presents abstracts on veterinary medicine topics which include reproductive performance in postpartum Rambouillet ewes and prepubertal ewe lambs treated with intravaginal progesterone, effect of bunk scoring on feedlot steer intake, and genetic parameter estimates for ultrasound indicators of carcass performance in Red Angus cattle.

The article presents a case study of a three-year-old Red Angus cow that was diagnosed with ovine herpesvirus-two along with malignant catarrhal fever (MCF). It mentions several symptoms of MCF including bilateral corneal edema, nasal discharge, and pyrexia. It suggests performing differential diagnosis of mature cattle with ocular and nasal lesions.

The article describes a study whose aim it was to determine if construction of additive genetic groups based on expected progeny differences (EPD) generated for the national cattle evaluation (NCE) of another breed will produce EPD in the current breed. Topics discussed include the Red Angus Association of America (RAAA) herd book including progeny from 1,324 animals.

The effect of pre-chill removal of kidney fat from bull carcasses on Longissimus palatability, histological and enzyme characteristics was studied. To better represent the time flow of product from packer to consumer, steaks were removed from one side of each carcass for evaluation after a 7-day chill. Carcasses having intact kidney fat exhibited firmer and more marbled Longissimus muscle, and this was reflected in slightly higher quality grades: low choice versus high select in carcasses having fat removed. No differences were observed in panel tenderness, shear force value, or histological and lysosomal enzyme characteristics. A slower pH decline was observed in muscle of carcasses with kidney fat removed. [ABSTRACT FROM AUTHOR]

In beef cattle, body weight is an important trait and optimizing size at various ages is of key economic interest. In our previous study, we identified four large-effect pleiotropic QTLs located on BTA6, 7, 14 and 20 associated with body weights in several beef breeds. Some 96 new functional variants of candidate genes within these and some other QTL regions were selected from the dbSNP and assayed into the new versions of GeneSeek Genomic Profilers (GGP-LD, GGP-UHD and GGP-50K). Some 5,964 Simmental and 2,871 Red Angus animals were genotyped with one of these assays. Some 200 animals of each population were used as the test and the rest for training purposes. Only 9,439 autosomal markers in common between these assays were used in the analyses. We compared accuracies of genomic predictions for birth, weaning and yearling weights fitting 9K, 9K plus 96 functional variants or only 96 functional variants in BayesC0 model using GenSel software. The correlations between estimated molecular breeding values (MBV) and adjusted phenotypes divided by the square root of the trait heritability were used as a measurement of accuracy, which are shown in Table 1. The accuracies of MBV were equal or higher in the model including additional 96 functional variants. Interestingly, genomic predictions were more accurate for yearling weight using only 96 functional variants in both Simmental and Red Angus populations. These functional variants accounted for significant amount of additive genetic variances of body weights in these populations. Some functional variants including rs109570900 encoding p.Ile442Met in NCAPG, rs109901274 encoding p.Tyr182Cys in ARRDC3, rs136369910 encoding g.25019900A>G in PLAG1 and rs43350563 encoding c.322G>A in ERGIC1 were among significantly associated markers with remarkable impact on body weights. Knowledge of such functional variants improves the accuracies of genomic predictions and would create new opportunities for the selection of animals with appropriate body weights for harvest or maternal purposes and could decrease dystocia in beef cattle population. Table 1. The accuracies of genomic predictions for birth, weaning and yearling weights using different marker sets Breed Trait 9K 9K plus 96 functional variants Only 96 functional variants Simmental Birth weight 0.60 0.60 0.15 Weaning weight 0.16 0.16 0.02 Yearling weight 0.19 0.21 0.40 Red Angus Birth weight 0.49 0.51 0.47 Weaning weight 0.23 0.23 0.27 Yearling weight 0.15 0.19 0.57 [ABSTRACT FROM AUTHOR]

Reproductive performance in cattle herds is one of the most critical factors influencing the economic viability of beef enterprises. Heifers that become pregnant as yearlings will have more calves over their lifetime and allow for greater recovery of heifer development costs. However, genetic improvement of the trait heifer pregnancy (HPG) under traditional genetic approaches is difficult due to low heritability and accuracy of selection. An approach to address this dilemma is to identify QTL that could be used to improve HPG. The objective of this study was to identify QTL associated with HPG in Red Angus cattle. A genome-wide association study (GWAS) was performed using deregressed HPG EBV, estimated using a single trait animal model and three generation pedigree formed from animals in the data used for national cattle evaluation performed during December 2014 for the Red Angus Association of America. Initially, animals were genotyped using various Illumina SNP chip-platforms ranging in density from 32,186 to 140,114 SNP. Genotype data were then imputed with FImpute so each animal (n = 9,380) possessed 74,659 SNP genotypes. Individual animals that contained a reported breed percent of >50 percent Red Angus with a deregressed EBV reliability greater than 0.05 were merged with the genotype file and marker quality control was performed yielding 567 animals. Criteria for sifting genotypes consisted of removing those markers where the average call rate was <0.85, minor allele frequency <0.01, those not in Hardy-Weinberg equilibrium (P < 0.0001), or those SNP in extreme LD (r2 > 0.99). These criteria left 64,010 SNP available for GWAS. Genomic windows of approximately 1 Mb (25.12 ± 8.31 SNP) in size were determined to significantly influence HPG if the size of their effect explained greater than 0.75% of the genetic variance in the trait. Bayes B in the software GenSel was used in GWAS. Two marker windows were associated with HPG. One QTL was located on bovine chromosome 28 and accounted for nearly 2% of the genetic variance, while the second on chromosome 11 accounted for 1.6% of the variance. These QTL results differ from other reports and suggest that QTL for HPG are not in concordance with GWAS results involving breeds such as Brangus and Simmental. Discovery of these QTL are encouraging for genetic improvement programs in Red Angus cattle. Continued genotyping and increased reporting across family lines within the Red Angus breed would serve to enhance these results. [ABSTRACT FROM AUTHOR]