Angus Cattle Research Articles

Physicochemical and Sensory Assessments in Spain and United States of PGI-Certified Ternera de Navarra vs. Certified Angus Beef.

The physicochemical and sensory differences between the PGI-Certified Ternera de Navarra (CTNA) (Spanish origin) and Certified Angus Beef (CAB) (US origin) were assessed in Spain and the USA. To characterize the carcasses, the ribeye areas (REAs), and marbling levels were assessed in both testing places. Twenty striploins per certified beef program were used as study samples. For sensory analysis, the striploins were vacuum packaged and aged for 7 days at 4 °C and 85% RH in each corresponding laboratory. Thereafter, the samples were half cut and frozen. One of the halves was shipped to the other counterpart-testing place. The fat and moisture percentage content, Warner Bratzler Shear Force (WBSF), and total and soluble collagen were tested for all the samples. The CAB carcasses had smaller REAs (p < 0.0001) and exhibited higher marbling levels (p < 0.0001). The CAB striploins had a higher fat content (p < 0.0001) and required lower WBSF (p < 0.05) than the CTNA samples. Trained panelists rated the CAB samples as juicer (p < 0.001), more tender/less tough (p < 0.0001), and more flavorful (p < 0.0001) than the CTNA counterparts. This study shows that beef from both countries had medium-high tenderness, juiciness, and beef flavor scores and very low off-flavor scores. Relevant differences found between the ratings assigned by the Spanish and the US panelists suggest training differences, or difficulties encountered in using the appropriate terminology for defining each sensory attribute. Furthermore, the lack of product knowledge (i.e., consumption habits) may have been another reason for such differences, despite the blind sensory evaluation.

Longevity and reproductive traits in Angus cattle: Genetic parameters, predicted and realized genetic change

The objectives of this study were to estimate genetic parameters for longevity and reproductive and to evaluate their likely consequences on selection. We used calving records of 10,517 Aberdeen Angus cows, born between 1975 and 2012, with first calving in spring, from bulls with 5 or more daughters, herds with 25 or more observations, and pertaining to contemporary groups of 5 or more cows. Longevity variables were length of productive life (LPL) and stayability at 5 years (ST5); the reproductive variables were days to first calving (days1), calving success at second parity (CS2), and success of having the first three consecutive calvings (S3). CS2, S3 and ST5 were defined as binary, and days1 and LPL as continuous variables. A multi-trait, threshold-linear model was used, including contemporary group effects (herd-year of birth; days1 also included management group), age at first calving (covariate), and the genetic effect of the animal. Given the parameters, five strategies were explored to predict annual genetic progress: selection of 5% or 25% of progeny tested males, with progeny groups of 5 or 15 daughters (no selection in females), and mass selection of 75% in females (no selection in males). Annual realized genetic trends and correlated responses when selecting for ST5, CS2 or S3 were also calculated. The estimates (mean ± standard deviation a posteriori) of heritability for longevity traits were 0.08±0.03 for LPL and 0.11±0.05 for ST5; for reproductive traits, estimations were 0.08±0.02 for days1, 0.23±0.04 for S3, and 0.24±0.04 for CS2. The genetic correlation between LPL and ST5 was favourable and large (0.79); and were also favourable and large for reproductive characteristics (negative, -0.66 for days1-S3 and -0.73 for days1-CS2, and positive, +0.83 for S3-CS2). Correlations between longevity and reproduction were variable, from not different from zero (days1 with ST5 and LPL) to medium (+0.45 for ST5-S3). Realized annual genetic trends indicated small but significant favourable changes for ST5 and LPL, and unfavorable for days1, CS2 and S3. Correlated responses were, in general, also favourable, although less than the progress achieved by direct selection. There are wide possibilities for genetic improvement in these characteristics.

Influence of Residual Feed Intake and Cow Age on Dry Matter Intake Post-Weaning and Peak Lactation of Black Angus Cows.

Simple SummarySupplemental nutrition for cattle is the greatest operating cost for cow-calf producers, accounting for 65% of the annual expenses. In addition, residual feed intake (RFI) is being used as a selection tool for purchasing and retaining heifers, as well as selecting bulls with the goal of improving feed efficiency and/or reducing supplemental inputs. However, the use and relevance of RFI as a selection tool for the cow-calf industry needs additional research. In our studies, heifer post-weaning RFI did not influence mature cow dry matter intake and intake behavior for both lactating and non-lactating beef cows. In contrast, cow age did correspond to increases of intake and intake rates of mature cows. However, when intake was expressed as g/kg body weight−1, no differences were observed with respect to cow age for lactating and non-lactating cows. Milk production was influenced by heifer post-weaning RFI in 5–6- and 8–9-year-old cows, however, did not influence 9–10-year-old cows. Therefore, our research suggests that cow age has greater impacts on dry matter intake than RFI, however, the relationship between RFI of heifers and subsequent mature cow milk production warrants further investigation.We evaluated heifer post-weaning residual feed intake (RFI) classification and cow age on dry matter intake (DMI) at two stages of production. Fifty-nine non-lactating, pregnant, (Study 1) and fifty-four lactating, non-pregnant (Study 2) commercial black Angus beef cows were grouped by age and RFI. Free-choice, hay pellets were fed in a GrowSafe feeding system. In Study 1, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.01) with an increase in DMI and intake rate with increasing cow age. In Study 2, cow DMI (kg/d) and intake rate (g/min) displayed a cow age effect (p < 0.02) with an increase in DMI and intake rate with increasing cow age. Milk production displayed a cow age × RFI interaction (p < 0.01) where both 5–6-year-old and 8–9-year-old low RFI cows produced more milk than high RFI cows. For both studies, intake and intake behavior were not influenced by RFI (p ≥ 0.16) or cow age × RFI interaction (p ≥ 0.21). In summary, heifer’s post-weaning RFI had minimal effects on beef cattle DMI or intake behavior, however, some differences were observed in milk production.

Trends in genetic diversity and the effect of inbreeding in American Angus cattle under genomic selection

BackgroundWhile the adoption of genomic evaluations in livestock has increased genetic gain rates, its effects on genetic diversity and accumulation of inbreeding have raised concerns in cattle populations. Increased inbreeding may affect fitness and decrease the mean performance for economically important traits, such as fertility and growth in beef cattle, with the age of inbreeding having a possible effect on the magnitude of inbreeding depression. The purpose of this study was to determine changes in genetic diversity as a result of the implementation of genomic selection in Angus cattle and quantify potential inbreeding depression effects of total pedigree and genomic inbreeding, and also to investigate the impact of recent and ancient inbreeding.ResultsWe found that the yearly rate of inbreeding accumulation remained similar in sires and decreased significantly in dams since the implementation of genomic selection. Other measures such as effective population size and the effective number of chromosome segments show little evidence of a detrimental effect of using genomic selection strategies on the genetic diversity of beef cattle. We also quantified pedigree and genomic inbreeding depression for fertility and growth. While inbreeding did not affect fertility, an increase in pedigree or genomic inbreeding was associated with decreased birth weight, weaning weight, and post-weaning gain in both sexes. We also measured the impact of the age of inbreeding and found that recent inbreeding had a larger depressive effect on growth than ancient inbreeding.ConclusionsIn this study, we sought to quantify and understand the possible consequences of genomic selection on the genetic diversity of American Angus cattle. In both sires and dams, we found that, generally, genomic selection resulted in decreased rates of pedigree and genomic inbreeding accumulation and increased or sustained effective population sizes and number of independently segregating chromosome segments. We also found significant depressive effects of inbreeding accumulation on economically important growth traits, particularly with genomic and recent inbreeding.

The characteristics of Sasra cattle, a local cattle from Sragen - Central Java

Efforts to conserve local cattle are important in order to get potential beef-producing cattle. A local cattle from Sragen District—Central Java, commonly referred to Sasra cattle, is one of the potential local cattle that will be developed. This study is intended to identify the characteristics of Sasra cattle, as part of the initial development steps. In 2017, a series of Focus Group Discussion was held by inviting historical actors, leaders, breeders, inseminators, the Sragen Regency Livestock and Fisheries Service officers, and Lembang’s Artificial Insemination Center to obtain historical data, characteristics, and farmer community responses related to the Sasra cattle. Body measurements (i.e. chest circumference, body length, and shoulder height) were taken in order to see the cattle performance. Genetical reviews of the molecular aspects have also been carried out. Results of the study showed that based on the history, Sasra cattle were a descent from the hibridization of Aberdeen Angus, American Brahman, and Ongole grade cattle breeds. Based on its phenotype, Sasra cattle could be characterized by the different head to body shape and color if compared to their ancestries, but at a glance, the body shape and color are close to the Angus cattle. There were 10 unique characteristics of Sasra cattle. The quantitative measurement of Sasra cattle is greater compared to that in other local cattle in Indonesia. Molecular evidence show that Sasra cattle have high similarity level to Bos indicus, than to Bos taurus and also confirms that Sasra cattle might have ancestry from Bos javanicus.

Effect of dietary restriction and compensatory growth on performance, carcass characteristics, and metabolic hormone concentrations in Angus and Belgian Blue steers

Compensatory growth (CG) is the ability of an animal to undergo accelerated growth after a period of restricted feeding. However, there is a dearth of information in relation to the effect of genotype on CG response, thus the objective of this study was to evaluate CG response in two contrasting breed types, namely Aberdeen Angus (AN) and Belgian Blue (BB). Crossbred AN × Holstein-Friesian or BB × Holstein-Friesian steers were assigned to one of two treatment groups in a two (genotypes) × two (diets) factorial design. For 99 days, one group (11 AN and 12 BB) was offered a high energy control diet (H-H) whereas the second group (11 AN and 12 BB) was offered an energy restricted diet (L-H). At the end of the differential feeding period (99 days), both groups of animals were then offered a high energy control diet for a further 200 days. All animals were then slaughtered on day-299 of the study. During feed restriction, L-H had lower DM intake (DMI), had greater feed conversion ratio (FCR) and lower plasma concentrations of insulin, IGF-1, leptin, glucose, urea, betahydroxybutyrate and smaller M. longissimus thoracis or lumborum muscle and fat depths compared to H-H steers. During realimentation, there was no difference in DMI between diets; however, L-H had greater live weight gain compared to H-H steers. Overall, H-H consumed greater quantities on a DM basis, however, had a higher FCR compared to L-H steers. By the end of the realimentation period, there was no difference in plasma metabolite or hormone concentrations, linear body measurements, ultrasonically scanned fat depths, carcass conformation, dressing percentage or fat class between H-H and L-H steers. At slaughter, carcass weights were affected by diet with greater values for H-H compared to L-H steers. Genotype affected measures associated with body composition including pelvic width and both muscle and fat depths (P < 0.05). Overall, L-H had a CG (or recovery) index of 0.52 and did not make up for the loss of gains during the differential feeding period; however, M. longissimus thoracis et lumborum, a tissue of high economic value, recovered completely making it a target of interest for further investigation.

Effect of Hair Coat Shedding Ability on Uterine Artery Hemodynamics in Angus Cattle

Abstract The objective of this study was to evaluate winter hair coat shedding ability and its association with uterine artery hemodynamics. Fall calving, artificially inseminated purebred Angus females (n = 29) were observed once monthly by two trained technicians for winter hair coat shedding and given a visual hair shedding score of 1 to 5 with 1 indicating 100% shed, 2 = 75%, 3 = 50%, 4 = 25%, and 5 indicating 0% shedding of winter hair coat. Month of first shedding (MFS) was determined once a female reached an average hair shedding score of ≤ 3.5 from March until July of 2019 and 2020. Uterine artery blood flow (ABF) was determined using color Doppler ultrasonography at d 150, 180, 210, and 240 of gestation. Total uterine artery (summation of ipsilateral and contralateral arteries) and ipsilateral uterine ABF, diameter, resistance and pulsatility index (PI) were analyzed using repeated measures of the MIXED procedure of SAS with significance declared at P ≤ 0.05. Fixed effects included MFS, day, year, and the respected interactions with covariates of dam body weight, ambient temperature and order of cows ultrasonography examination considered as a random effect. No significant MFS by day of gestation interaction (P &amp;gt; 0.32) was observed for total or ipsilateral ABF (P &amp;gt; 0.23). A MFS by day of gestation (P &amp;lt; 0.04) interaction was observed for both ipsilateral artery diameter and PI, in which females that shed by May had smaller artery diameter (0.74 vs. 0.85 cm) at day 180 of gestation and greater PI (P &amp;lt; 0.02; 1.48 vs. 1.03) at day 150 of gestation compared to June. Shedding ability had an effect on ipsilateral uterine artery development and pulsatility during gestation, possibly affecting the amount of nutrients distributed to the prenatal fetus and subsequent birth weight of the calf from females that shed by May.

32 Assessment of Dry-Aged Beef from Commercial Aging Locations Across the United States

Abstract Dry-aging is a practice that involves storing meat at refrigerated temperatures without protective packaging. Despite the increase in dry-aged beef popularity, relatively little is known about commercial dry-aging parameters. Thus, the objectives of this study were to determine dry-aging parameters of commercial aging facilities and their influence on eating quality (acceptability, flavor, tenderness, and juiciness) of dry-aged beef from locations across the United States. Sixty-six Certified Angus Beef® brand bone-in beef strip loins (IMPS #175) were randomly assigned to ten commercial dry-aging facilities across the United States. An additional six strip loins were wet-aged for 45-days as a negative control. Strip loins were shipped overnight to aging locations where a 45-day dry aging period transpired before being returned for subsequent analysis, upon completion of aging. Objective color, pH, and water activity were measured post aging, at the time of processing. Strip loins were then fabricated, and steaks were vacuum packaged and frozen until further analysis. Intrinsic quality parameters objective color (L*, a*, b*), pH, and water activity were not different (P &amp;gt; 0.05) between strip loins aged 45 days by location. Cooler conditions including temperature, percent relative humidity, and air speed were different (P &amp;lt; 0.01) across aging locations. Pacific Northwest consumer panelists indicated a difference in overall acceptability (P &amp;lt; 0.01), tenderness (P = 0.01), and flavor (P &amp;lt; 0.01) based on aging location. Additionally, consumers detected (P &amp;lt; 0.01) unique dry-aging flavors for individual aging locations including cheesy and nutty attributes. Research indicates individual dry-aging facility conditions aid in producing unique dry-aged beef products according to U.S. consumers from the Pacific Northwest Region.

21 Effect of Corn Silage Inclusion Rate on Live Growth Performance, Carcass Characteristics, Net Energy Utilization and Beef Production Per Hectare in Feedlot Finishing Steers

Abstract Maine-Anjou × Angus beef steers (n = 156; initial BW 366 ± 37.2 kg) were used in a finishing experiment at the Ruminant Nutrition Center in Brookings, SD. Steers were weighed on 2 consecutive days and assigned into 5 weight blocks (replicate pens). Treatments were arranged in a 2 × 2 factorial, 2 types of implants and 2 dietary treatments. Dietary treatments consisted (DM basis) of 1) 15% (CS15) or 2) 30% corn silage (CS30). Other ingredients consisted of DRC, HMC, liquid supplement and a dry supplement. The NEm, NEg and CP of CS15 was 94.8 Mcal/45.4 kg, 64.0 Mcal/45.4 kg and 12.7% and 91.2 Mcal/45.4 kg, 61.1 Mcal/45.4 kg, and 12.5% respectively (DM basis) for CS30. Bunks were managed using a slick bunk approach and all diets contained (DM basis) 33 mg/kg monensin sodium. Corn silage yield was assumed to be 45.7 Mg/ha and corn grain yield was calculated to be 10.2 Mg/ha. Beef production per hectare was calculated as (carcass adjusted final BW – initial BW)/hectare. No interaction between diet and implant (P ≥ 0.16) was detected for any variables. Final BW, ADG, and G:F were increased (P ≤ 0.02) by 2.2%, 6.5% and 7.2% respectively for CS15. Observed NE and the ratio of observed-to-expected NE for maintenance and gain was not influenced (P ≥ 0.15) by treatment. Dressing percent (64.52 vs. 63.47 ± 0.250; P = 0.01) and HCW (379 vs. 371 ± 13.1 kg; P = 0.02) were greater in CS15. Beef production per hectare was not impacted (P = 0.76) by feeding greater levels of corn silage. Feeding CS15 resulted in greater carcass-adjusted growth performance and HCW. No differences in beef produced per hectare of crop land means producers can feed greater inclusions of corn silage to finishing cattle without impacting carcass quality or beef production.

PSIII-6 Gene Expression Profile of Beef Heifer Placental Caruncles Is Affected by Pre-breeding and Early Gestation Micronutrient Supplementation

Abstract Vitamins and minerals are essential for proper fetal and placental development and function. However, the impact of micronutrient supplementation on placental function and gene expression remains unclear. Herein, we performed a transcriptomic analysis to determine the impact of pre-breeding maternal micronutrient supplementation on the gene expression of placental caruncles (CAR; maternal placenta). Crossbred Angus beef heifers were supplemented (VTM, n = 7) or not (CON, n = 7) with 113 g•heifer-1•d-1 of mineral premix (Purina® Wind &amp; Rain® Storm® All-Season 7.5 Complete) from d 71 to 148 before breeding and until d 83 of gestation. After breeding, heifers were fed a diet to gain 0.79 kg/d. Uteroplacental tissues were collected at d 83. The largest placentome closest to the fetus was collected, and CAR was manually dissected from the cotyledon. Total RNA was isolated from CAR, and gene expression was measured with RNA-Seq. After data quality control and read mapping, differential expression was performed using DESeq2. We identified 46 upregulated and 19 downregulated genes in the VTM group (adj.Pval &amp;lt; 0.1). ShinyGO pathway analysis software was used to identify genes in the Ca and CGMP-PKG signaling pathways, including CALM2 and CAMK2G, which were down and upregulated, respectively. Calcium-mediated systems may activate steroidogenic activity in bovine placentomes, while the cGMP-PKG pathway plays a key role in vascular homeostasis mediated by nitric oxide and decreased Ca concentrations. Furthermore, biological processes underlying blood circulation were among those over-represented. Previous studies report that maternal nutrition may impact placental vascularity and uterine blood flow. ATP2B, that is upregulated in the VTM group, is a calcium/calmodulin-regulated, magnesium-dependent protein involved in intracellular Ca homeostasis. In summary, pre-breeding and early gestation maternal micronutrient supplementation leads to differential expression of genes involved in Ca homeostasis and has a putative effect on placenta vascular function.

PSIV-1 Effect of Corn Silage Inclusion Rate on Apparent Total Tract Digestibility of Dry Matter, Organic Matter, and Crude Protein in Finishing Steers

Abstract Maine-Anjou × Angus beef steers (n = 156; initial BW 366 ± 37.2 kg) were used in a finishing experiment at the Ruminant Nutrition Center in Brookings, SD. Steers were weighed on 2 consecutive days and assigned into 5 weight blocks. Treatments were arranged in a 2 × 2 factorial, 2 types of implants and 2 dietary treatments with 5 replicate pens for each simple effect. Dietary treatments consisted (DM basis) of 1) 15% (CS15) or 2) 30% corn silage (CS30). Other ingredients consisted of a 50:50 blend of DRC and HMC, liquid supplement and a dry supplement. Bunks were managed using a slick bunk approach and all diets contained (DM basis) 33 mg/kg monensin sodium. Feed collections occurred during the morning and afternoon feedings for two days prior to fecal collections. Each feed sample was composited in equal amounts to create a single sample for each pen. Two fecal collections from each steer occurred 7 hours apart on day 112 of the study. Feces from each steer were composited in equal amounts to create a pen sample. All samples were dried and ground through a 1-mm screen. Acid insoluble ash was used as an internal marker. Apparent total tract digestibility was calculated using the equation: 100-100 ˣ (feed marker/fecal marker) × (fecal variable/feed variable). No interaction between implant and diet was detected for any variables (P ≥ 0.08). One pen was removed from the statistical analysis due to all values being 3 standard deviations away from the mean. Intake did not differ between CS15 and CS30 (P = 0.41). Fecal output was increased 36.9% (P = 0.01) in CS30. Dry matter, organic matter, and crude protein digestion were decreased by feeding CS30 (11.47%, 10.83%, 16.35% respectively; P ≤ 0.03). As corn silage inclusion increases, digestibility coefficients for DM, OM, and CP are decreased.

Genetic potential for residual feed intake and diet fed during early- to mid-gestation influences post-natal DNA methylation of imprinted genes in muscle and liver tissues in beef cattle.

Discovery of epigenetic modifications associated with feed efficiency or other economically important traits would increase our understanding of the molecular mechanisms underlying these traits. In combination with known genetic markers, this would provide opportunity to improve genomic selection accuracy in cattle breeding programs. It would also allow cattle to be managed to improve favorable gene expression. The objective of this study was to identify variation in DNA methylation between beef cattle of differential pre-natal nutrition and divergent genetic potential for residual feed intake (RFI). Purebred Angus offspring with the genetic potential for either high (HRFI) or low (LRFI) RFI were prenatally exposed to either a restricted maternal diet of 0.5 kg/d average daily gain (ADG) or a moderate maternal diet of 0.7 kg/d ADG from 30 to 150 d of gestation. We performed DNA methylation analysis of differentially methylated regions (DMR) of imprinted genes (Insulin-like growth factor 2 (IGF2) DMR2, IGF2/H19 imprinting control region (ICR) and IGF2 receptor (IGF2R) DMR2) using post-natal samples of longissimus dorsi (LD) muscle taken from male and female calves at birth and weaning, and of LD muscle, semimembranosus (SM) muscle, and liver samples collected from steers at slaughter (17 months of age). Interestingly, for all three DMR investigated in liver, LRFI steers had higher levels of methylation than HRFI steers. In LD muscle, IGF2/H19 ICR methylation differences for heifers at birth were due to pre-natal diet, while for steers at birth they were mostly the result of genetic potential for RFI with LRFI steers again having higher levels of methylation than HRFI steers. While results from repeated measures analysis of DNA methylation in steers grouped by RFI revealed few differences, in steers grouped by diet, we found higher methylation levels of IGF2 DMR2 and IGF2R DMR2 in LD muscle of restricted diet steers at weaning and slaughter than at birth, as well as increased methylation in LD muscle of restricted diet steers compared with moderate diet steers at weaning and/or slaughter. Our results suggest that differential pre-natal nutrition, and divergent genetic potential for RFI, induces tissue- and sex-specific alterations in post-natal IGF2 and IGF2R methylation patterns and that these patterns can vary with age in Angus beef cattle.

The Molecular Bases Study of the Inherited Diseases for the Health Maintenance of the Beef Cattle.

The article highlighted the problem of meat cattle genetic defects. The aim was the development of DNA tests for some genetic defects diagnostics, the determination of the animal carriers and their frequencies tracking in time. The 1490 DNA samples from the Aberdeen Angus (n = 701), Hereford (n = 385), Simmental (n = 286) and Belgian Blue (n = 118) cattle have been genotyped on the genetic defects by newly created and earlier developed DNA tests based on AS-PCR and PCR-RFLP methods. The Aberdeen Angus cattle genotyping has revealed 2.38 ± 0.31% AMC-cows and 1.67 ± 0.19 % AMC-bulls, 0.65 ± 0.07% DDC-cows and 0.90 ± 0.10% DDC-bulls. The single animals among the Hereford cattle were carriers of MSUD and CWH (on 0.27 ± 0.05%), ICM and HY (on 0.16 ± 0.03%). The Simmental cattle were free from OS. All Belgian Blue livestock were M1- and 0.84%-CMD1-carriers. The different ages Aberdeen Angus cattle genotyping has shown the tendency of the AMC- and DDC frequencies to increase in the later generations. The statistically significant increase of DDC of 1.17% in the cows’ population born in 2019 compared to those born in 2015 allows concluding the further development of the DNA analysis-based measures preventing the manifestation of the genetic anomalies in meat cattle herds is necessary.

Screening of backfat thickness and musculus longissimus lumborum et thoracis depth of Aberdeen Angus cattle in Czech condition

The aim of this study was to monitor the Czech Aberdeen Angus population for backfat thickness (BT), musculus longissimus lumborum et thoracis (MUSCLE) and live weight (LW) in relation to environmental and genetic conditions. In this study, we also wanted to display the potential for future inclusion of these parameters into national monitoring. Parameters of BT, MUSCLE and LW were measured at 120, 210, and 365 days of age in 769 Aberdeen Angus calves (417 bulls and 352 heifers) on seven farms. Statistical evaluation was performed in the SAS v9.3 software. The bulls achieved significantly higher (P &amp;lt; 0.01) weights and larger MUSCLE compared to the heifers, although the heifers had higher BT. The age of the dam at calving significantly influenced the growth ability of tested calves, but it did not influence BT nor MUSCLE. The nested effect of the year-season, farm and sire bulls (or genetic background) significantly affected LW, BT and MUSCLE of tested calves. The use of the same breeding bulls on different farms resulted in significant differences in growth parameters. Our results displayed the potential of nationwide monitoring of MUSCLE and BT of beef breeds, as official parameters of the beef performance testing in the Czech Republic. The inclusion of these globally used traits in the Czech breeding system would allow to predict breeding values for the Czech beef population. This would lead not only to general improvement of MUSCLE in the population, but also to the production of better breeding animals and slaughter animals with higher value.

Hair coat score in Angus cattle: Comparison of linear and threshold models, genetic gain and correlations with growth, morphological and reproductive traits

Hair coat traits are used as indicators of animal adaptation because of their importance for thermoregulation and parasites resistance. These traits are evaluated visually based on a score in some beef cattle breeding programs. Data from 38,800 Angus animals were used to compare linear and threshold animal models in order to validate genetic parameters for visual scores of hair coat at weaning (WHC) and yearling (YHC), and conformation (YC), precocity (YP) and muscling (YM) at yearling. The genetic trends for WHC and YHC and their relationships with YC, YP, YM, birth weight (BW), weight gain from birth to weaning (BWG) and from weaning to yearling (YWG), scrotal circumference (SC), and gestation length (GL) were also obtained. For WHC and YHC, higher heritabilities were estimated with the threshold models (0.249±0.039 and 0.295±0.041, respectively) compared to the linear models (0.188±0.029 and 0.218±0.032, respectively). However, similar heritabilities were obtained with the two models for YC, YP and YM. Rank correlations between sire breeding values predicted for WHC and YHC using linear and threshold models ranged from 0.75 to 0.95, considering the top 2 to 50% of the selected sires. For YC, YP and YM, small changes in sire ranking are expected when these models are used (rank correlations higher than 0.86), regardless of the proportion of selected sires. Cross-validation strategies by regression showed that genetic selection for all visual scores will also promote improvements in phenotypic performance. Genetic trends were significant (P<0.05) and favorable for WHC and YHC. The genetic correlation between WHC and YHC was high and positive (0.848±0.055). Favorable and moderate genetic associations were estimated for WHC and YHC with YC, YP, YM, BWG and WYG, ranging from -0.329±0.108 to -0.589±0.07. The genetic correlations of WHC and YHC with BW, SC and GL were weaker and negative. According to our results, the threshold model is recommended for genetic evaluation of WHC and YHC in this population, and both models are indicated for YC, YP and YM. In general, genetic selection to increase growth, YC, YP, YM and SC will simultaneously reduce WHC and YHC, favoring animals that are more adapted to the environmental conditions of the tropics.

Impacts of heifer postweaning residual feed intake classification on reproductive and performance measurements of first-, second-, and third-parity Angus beef females.

This study evaluated heifer postweaning residual feed intake (RFI) classification on reproductive and performance measurements of first-, second-, and third-parity Angus beef females. We analyzed the annual, as well as, cumulative production of 347 Angus females from birth through weaning of their third calf. Heifer postweaning RFI was calculated as the actual dry matter intake minus the predicted dry matter intake based on the average daily gain of the contemporary group on an annual basis. Heifers were categorized based on RFI as either low (< −0.50 SD from mean), average (± 0.50 SD from mean), or high (> +0.50 SD from the mean) within year. There was no RFI × Parity interaction (P ≥ 0.14) observed for all production/reproduction traits except for conception rates (P = 0.02). Julian birth date of cows was influenced by RFI classification (P < 0.01) and displayed a quadratic (P = 0.02) effect with high RFI cows being born earlier in the calving season than average RFI cows (71.2 vs. 75.3 d), but did not differ from low RFI cows (74.0 vs. 75.3 d). Cow birth weight, weaning weight, as well as all other cow weight and body condition measurements were not influenced by RFI classification (P ≥ 0.14). As expected, there was a linear increase in cow body weight at weaning with increasing parity (P < 0.01). Cow RFI classification had no influence on progeny weaning weight, birth date, calving interval, or postpartum interval (P ≥ 0.15). Calf birth weights displayed a quadratic parity effect (P < 0.01) with first calf heifers having calves with lower birth weights than second- and third-parity calves. Calf 205-d adjusted weaning weights displayed a quadratic effect (P = 0.01) with first calf heifers weaning lighter calves than second- and third-parity cows. Weaning weight ratio displayed a linear decrease with increasing parity (P < 0.01). Cow conception probability displayed a linear tendency for pregnancy 2 (P = 0.09), and a quadratic tendency for pregnancy 4 (P = 0.07) as a function of RFI classification, but no effects were observed for pregnancy 1 and 3. Cow artificial insemination conception rates differed by year of pregnancy (P < 0.01), but not RFI classification (P = 0.81). In summary, heifer postweaning RFI classification had minimal effects on beef cattle production and reproductive efficiency.

Is meat from cull cows tougher?

Meat from cull cows is traditionally sold in Australia for mincemeat, but this study examined whether there is potential to add value by identifying meat of higher quality from older cattle. Dentition and ossification score were recorded for 173 Angus cattle of known age, ranging from 26 months to 12.6 years. Longissimus and semitendinosus muscles were sampled to assess the effect of chronological age on shear force and connective tissue. Age explained variation in shear force of the semitendinosus better than in the longissimus muscle, but had little effect on shear force values per se. At 2 days postmortem, 18% of the longissimus muscles were classified as tender reaching 65% as ageing extended to 14 days. Soluble collagen was a better predictor of age than total collagen. This study shows that the current practice of routinely selling meat from culled cows as mincemeat overlooks a valuable opportunity to grade and sell a significant proportion at higher price as prime cuts.

Genetic parameter estimations and genomic insights for teat and udder structure in young and mature Canadian Angus cows.

Poor teat and udder structure, frequently associated with older cows, impact cow production and health as well as calf morbidity and mortality. However, producer culling, for reasons including age, production, feed availability, and beef markets, creates a bias in teat (TS) and udder scores (US) assessed and submitted to the Canadian Angus Association for genetic evaluations toward improved mammary structure. In addition, due to the infancy of the reporting program, repeated scores are rare. Prior to the adoption of genetic evaluations for TS and US in Canadian Angus cattle, it is imperative to verify that TS and US from young cows are the same traits as TS and US estimated on mature cows. Genetic parameters for TS and US from all cows (n = 4,192) and then from young cows (parities 1 and 2) and from mature cows (parity ≥ 4) were estimated using a single-trait animal model. Genetic correlations for the traits between the two cow age groups were estimated using a two-trait animal model. Estimates of heritability (posterior SD [PSD]) were 0.32 (0.07) and 0.45 (0.07) for young TS and US and 0.27 (0.07) and 0.31 (0.07) for mature TS and US, respectively. Genetic correlation (PSD) between the young and mature traits was 0.87 (0.13) for TS and 0.40 (0.17) for US. Genome-wide association studies were used to further explore the genetic and biological commonalities and differences between the two groups. Although there were no genes in common for the two USs, 12 genes overlapped for TS in the two cow age groups. Interestingly, there were also 23 genes in common between TS and US in mature cows. Based on these findings, it is recommended that producers collect TS and US on their cow herd annually.

Impact of Censored or Penalized Data in the Genetic Evaluation of Two Longevity Indicator Traits Using Random Regression Models in North American Angus Cattle.

Simple SummaryCow longevity is a key driver of the beef cattle industry profitability that can be improved through genetic and genomic selection. Censored data are commonly dealt with in genetic evaluations of longevity, which can unfavorably impact the accuracy of breeding values and the rates of genetic progress. In this study, we evaluated alternative scenarios to define the best approaches for genetically evaluating longevity in North American Angus cattle in the presence of censored data.This study aimed to evaluate the impact of different proportions (i.e., 20%, 40%, 60% and 80%) of censored (CEN) or penalized (PEN) data in the prediction of breeding values (EBVs), genetic parameters, and computational efficiency for two longevity indicators (i.e., traditional and functional longevity; TL and FL, respectively). In addition, three different criteria were proposed for PEN: (1) assuming that all cows with censored records were culled one year after their last reported calving; (2) assuming that cows with censored records older than nine years were culled one year after their last reported calving, while censored (missing) records were kept for cows younger than nine years; and (3) assuming that cows with censored records older than nine years were culled one year after their last reported calving, while cows younger than nine years were culled two years after their last reported calving. All analyses were performed using random regression models based on fourth order Legendre orthogonal polynomials. The proportion of commonly selected animals and EBV correlations were calculated between the complete dataset (i.e., without censored or penalized data; COM) and all simulated proportions of CEN or PEN. The computational efficiency was evaluated based on the total computing time taken by each scenario to complete 150,000 Bayesian iterations. In summary, increasing the CEN proportion significantly (p-value < 0.05 by paired t-tests) decreased the heritability estimates for both TL and FL. When compared to CEN, PEN tended to yield heritabilities closer to COM, especially for FL. Moreover, similar heritability patterns were observed for all three penalization criteria. High proportions of commonly selected animals and EBV correlations were found between COM and CEN with 20% censored data (for both TL and FL), and COM and all levels of PEN (for FL). The proportions of commonly selected animals and EBV correlations were lower for PEN than CEN for TL, which suggests that the criteria used for PEN are not adequate for TL. Analyses using COM and CEN took longer to finish than PEN analyses. In addition, increasing the amount of censored records also tended to increase the computational time. A high proportion (>20%) of censored data has a negative impact in the genetic evaluation of longevity. The penalization criteria proposed in this study are useful for genetic evaluations of FL, but they are not recommended when analyzing TL.

Histochemical characterisation of high-value beef muscles from different breeds, and its relation to tenderness.

ABSTRACT The aim of the present study was to characterise and compare the muscle fibre traits of five muscles: longissimus lumborum (LL), semitendinosus (ST), biceps femoris (BF), semimembranosus (SM) and psoas major (PM) collected from four cattle breeds (Aberdeen Angus, AA; Gascon, GS; Holstein, HO; Fleckvieh, FL) differing in maturity type (early- and late-maturing) and production purpose (beef and dairy), but maintained under identical husbandry conditions. The relationships between histochemical characteristics and instrumental meat tenderness (Warner-Bratzler shear force) were evaluated. The most significant differences in muscle fibre traits were seen in the hindquarter muscles of Aberdeen Angus and Gascon cattle, with muscle location also having a large effect on tenderness. Under the identical husbandry practises used, the differences in muscle fibre composition were seemingly linked more so to muscle location and maturity type of the breed, rather than the production purpose of the breed. Based on their effects on high-value muscles in beef breeds, continuous evaluation of muscle fibre traits together with their association with various meat quality traits is required, as breeds progress genetically. However, various intrinsic and extrinsic factors, such as husbandry practises, need to be controlled so that accurate conclusions may be drawn from such investigations.