Angus Cattle Research Articles

A look under the hood of genomic-estimated breed compositions for brangus cattle: What have we learned?

The Brangus cattle were developed to utilize the superior traits of Angus and Brahman cattle. Their genetic compositions are expected to be stabilized at 3/8 Brahman and 5/8 Angus. Previous studies have shown more than expected Angus lineage with Brangus cattle, and the reasons are yet to be investigated. In this study, we revisited the breed compositions for 3,605 Brangus cattle from three perspectives: genome-wise (GBC), per chromosomes (CBC), and per chromosome segments (SBC). The former (GBC) depicted an overall picture of the "mosaic" genome of the Brangus attributable to their ancestors, whereas the latter two criteria (CBC and SBC) corresponded to local ancestral contributions. The average GBC for the 3,605 Brangus cattle were 70.2% Angus and 29.8% Brahman. The K-means clustering supported the postulation of the mixture of 1/2 Ultrablack (UB) animals in Brangus. For the non-UB Brangus animals, the average GBC were estimated to be 67.4% Angus and 32.6% Brahman. The 95% confidence intervals of their overall GBC were 60.4%-73.5% Angus and 26.5%-39.6% Brahman. Possibly, genetic selection and drifting have resulted in an approximately 5% average deviation toward Angus lineage. The estimated ancestral contributions by chromosomes were heavily distributed toward Angus, with 27 chromosomes having an average Angus CBC greater than 62.5% but only two chromosomes (5 and 20) having Brahman CBC greater than 37.5%. The chromosomal regions with high Angus breed proportions were prevalent, tending to form larger blocks on most chromosomes. In contrast, chromosome segments with high Brahman breed proportion were relatively few and isolated, presenting only on seven chromosomes. Hence, genomic hitchhiking effects were strong where Angus favorable alleles resided but weak where Brahman favorable alleles were present. The functions of genes identified in the chromosomal regions with high ( ) Angus compositions were diverse yet may were related to growth and body development. In contrast, the genes identified in the regions with high ( ) Brahman compositions were primarily responsible for disease resistance. In conclusion, we have addressed the questions concerning the Brangus genetic make-ups. The results can help form a dynamic picture of the Brangus breed formation and the genomic reshaping.

Foraging behavior of Raramuri Criollo vs. Angus cattle grazing California Chaparral and Colorado Plateau shrublands

Selecting livestock genetics adapted to arid environments, such as Criollo cattle, is one of several strategies recommended for decreasing the vulnerability to climate change of ranching in the southwestern USA. Our objective was to determine whether desirable foraging traits of Criollo cattle previously documented in the Chihuahuan Desert, held true in two of the most climate-vulnerable ecosystems of the Southwest. We conducted a study at Rancho Corta Madera (RCM) in southern California and Dugout Ranch (DR) in southeast Utah. Twenty mature cows, 10 Raramuri Criollo and 10 Red or Black Angus, were monitored with GPS collars during multiple seasons between 2018 and 2021. Geolocation data were used to compute daily distance traveled (km*d−1), movement velocity (m*min−1), path sinuosity (SI), time spent grazing, resting, or traveling (h*d−1), and area of the pasture explored (ha*d−1) as well as to calculate selection of vegetation cover types (E, Ivlev's Electivity Index) by cows of each breed. The effects of breed, season, year, and pasture on each of these metrics were modeled with repeated measures analyses of variance. At both ranches, statistically detectable differences (P ≤ 0.05) between breeds were observed for most behavior metrics during the dormant season. Conversely, few breed differences were observed during the growing season. Criollo cattle exhibited greater relative preference for a number of shrub dominated vegetation types at both ranches, and similar relative selection of grassland dominated sites compared to Angus counterparts. At both ranches, Criollo cattle exhibited similar or less relative preference for riparian areas vs. Angus counterparts. Breed divergence vs. convergence of foraging behaviors during the dormant vs. growing seasons, previously observed in the Chihuahuan Desert, was documented at both sites. Positive system outcomes associated with foraging traits of Criollo cattle could be expected to occur more broadly across the Southwest.

Dynamic distribution of gut microbiota in cattle at different breeds and health states.

Weining cattle is a precious species with high tolerance to cold, disease, and stress, and accounts for a large proportion of agricultural economic output in Guizhou, China. However, there are gaps in information about the intestinal flora of Weining cattle. In this study, high-throughput sequencing were employed to analyze the intestinal flora of Weining cattle (WN), Angus cattle (An), and diarrheal Angus cattle (DA), and explore the potential bacteria associated with diarrhea. We collected 18 fecal samples from Weining, Guizhou, including Weining cattle, Healthy Angus, and Diarrheal Angus. The results of intestinal microbiota analysis showed there were no significant differences in intestinal flora diversity and richness among groups (p > 0.05). The abundance of beneficial bacteria (Lachnospiraceae, Rikenellaceae, Coprostanoligenes, and Cyanobacteria) in Weining cattle were significantly higher than in Angus cattle (p < 0.05). The potential pathogens including Anaerosporobacter and Campylobacteria were enriched in the DA group. Furthermore, the abundance of Lachnospiraceae was very high in the WN group (p < 0.05), which might explain why Weining cattle are less prone to diarrhea. This is the first report on the intestinal flora of Weining cattle, furthering understanding of the relationship between intestinal flora and health.

Periconceptual Maternal Nutrition Affects Fetal Liver Programming of Energy- and Lipid-Related Genes.

During pregnancy, the fetus relies on the dam for its nutrient supply. Nutritional stimuli during fetal organ development can program hepatic metabolism and function. Herein, we investigated the role of vitamin and mineral supplementation (VTM or NoVTM-at least 71 days pre-breeding to day 83 of gestation) and rate of weight gain (low (LG) or moderate (MG)-from breeding to day 83) on the fetal liver transcriptome and the underlying biological pathways. Crossbred Angus beef heifers (n = 35) were randomly assigned to one of four treatments in a 2 × 2 factorial design (VTM_LG, VTM_MG, NoVTM_LG, and NoVTM_MG). Gene expression was measured with RNA-Seq in fetal livers collected on day 83 ± 0.27 of gestation. Our results show that vitamin and mineral supplementation and rate of weight gain led to the differential expression of hepatic genes in all treatments. We identified 591 unique differentially expressed genes across all six VTM-gain contrasts (FDR ≤ 0.1). Over-represented pathways were related to energy metabolism, including PPAR and PI3K-Akt signaling pathways, as well as lipid metabolism, mineral transport, and amino acid transport. Our findings suggest that periconceptual maternal nutrition affects fetal hepatic function through altered expression of energy- and lipid-related genes.

Adaptation of the Third Generation Aberdeen Angus Heifers in the North Kazakhstan Region

The article presents research materials on the adaptive and productive qualities of the third-generation heifers of Aberdeen Angus cattle in the conditions of the "Zholdasbay-agro" farming enterprise of the North Kazakhstan region. The object of study was the growth and development of third-generation heifers obtained by Canadian and European selection of the Aberdeen-Angus breed. According to the results of the study and the summary of clinical signs, the frequency of antenatal hypotrophy in newborn calves of the Aberdeen-Angus breed of Canadian selection was 12.3%, European 8.7%. The research results showed that the relative growth rate in European calves up to 6 months is higher than in peers of Canadian breeding, but in the period from 6 to 8 months, calves obtained from cows of the second generation of Canadian breeding are superior to calves of European selection. The established tendency of a lower growth rate of heifers obtained from cows of Canadian breeding may be associated with an increase in the tension of regulatory mechanisms that ensure the adaptation of animals to new environmental conditions.

Environmental impacts and animal performance of finishing bulls fed different silage-based total mixed rations

The objective of this study was to evaluate the effects of three different grass silage (GS) based diets on environmental impacts and animal performance of finishing bulls. Experiment 1 (Exp 1) was conducted using 53 Aberdeen angus (AA) and 52 Simmental (SI) beef bulls and experiment 2 (Exp 2) included 69 Holstein (HO) and 36 Nordic Red (NR) dairy bulls. The three experimental diets included three different proportions of concentrates and two different types of forages. Moderate concentrate diet (MC) included GS, barley grain and mineral-vitamin mixture in proportions of 600:385:15 on dry matter (DM) basis while the respective proportions on low concentrate diet (LC) were 850:135:15. No concentrate diet (NC) included GS, whole crop barley silage and mineral-vitamin mixture (685:300:15). The bulls were fed total mixed rations ad libitum. Environmental impacts of the dietary treatments were estimated using a gate-to-gate life cycle assessment approach with the following key impact categories; global warming potential (GWP), eutrophication, and acidification potential. In Exp 1 the carcass gain, carcass weight and carcass conformation of the SI bulls were 10, 8 and 23% higher, respectively, compared to the AA bulls (P < 0.001) but there was no difference in feed conversion (kg DM/kg carcass gain) between AA and SI. In Exp 2 the NR bulls had 12% better conformed carcasses compared to the HO bulls (P < 0.001) but the carcass gain of the HO bulls tended to be 4% higher (P = 0.06) compared to NR. There was no difference in feed conversion or carcass weight between HO and NR. In both experiments, LC and NC diets impaired growth performance, feed conversion and carcass conformation compared to MC. In Exp 1 the GWP was 19.1 kg CO2 eq/kg of produced beef during the experiment with MC, 20.7 kg with LC and 25.9 kg with NC. Eutrophic emissions were 17.1, 21.3 and 21.8 g PO4 eq/kg of produced beef and acidifying emissions 38.6, 49.9 and 53.7 AE eq/kg of produced beef, respectively for MC, LC, and NC treatments. In Exp 2 the GWP was 20.7, 21.7 and 26.3 CO2 eq/kg of produced beef, eutrophic emissions 16.4, 18.9 and 20,8 PO4 eq/kg of produced beef and acidifying emissions 39.4, 50.6 and 59.2 AE eq/kg of produced beef for MC, LC, and NC treatments, respectively. It can be concluded that impaired feed conversion in LC and NC diets led to the higher environmental impacts compared to MC.

Unraveling the phenotypic and genomic background of behavioral plasticity and temperament in North American Angus cattle

BackgroundLongitudinal records of temperament can be used for assessing behavioral plasticity, such as aptness to learn, memorize, or change behavioral responses based on affective state. In this study, we evaluated the phenotypic and genomic background of North American Angus cow temperament measured throughout their lifetime around the weaning season, including the development of a new indicator trait termed docility-based learning and behavioral plasticity. The analyses included 273,695 and 153,898 records for yearling (YT) and cow at weaning (CT) temperament, respectively, 723,248 animals in the pedigree, and 8784 genotyped animals. Both YT and CT were measured when the animal was loading into/exiting the chute. Moreover, CT was measured around the time in which the cow was separated from her calf. A random regression model fitting a first-order Legendre orthogonal polynomial was used to model the covariance structure of temperament and to assess the learning and behavioral plasticity (i.e., slope of the regression) of individual cows. This study provides, for the first time, a longitudinal perspective of the genetic and genomic mechanisms underlying temperament, learning, and behavioral plasticity in beef cattle.ResultsCT measured across years is heritable (0.38–0.53). Positive and strong genetic correlations (0.91–1.00) were observed among all CT age-group pairs and between CT and YT (0.84). Over 90% of the candidate genes identified overlapped among CT age-groups and the estimated effect of genomic markers located within important candidate genes changed over time. A small but significant genetic component was observed for learning and behavioral plasticity (heritability = 0.02 ± 0.002). Various candidate genes were identified, revealing the polygenic nature of the traits evaluated. The pathways and candidate genes identified are associated with steroid and glucocorticoid hormones, development delay, cognitive development, and behavioral changes in cattle and other species.ConclusionsCow temperament is highly heritable and repeatable. The changes in temperament can be genetically improved by selecting animals with favorable learning and behavioral plasticity (i.e., habituation). Furthermore, the environment explains a large part of the variation in learning and behavioral plasticity, leading to opportunities to also improve the overall temperament by refining management practices. Moreover, behavioral plasticity offers opportunities to improve the long-term animal and handler welfare through habituation.

Comparison between indicine and taurine cattle DNA methylation reveals epigenetic variation associated to differences in morphological adaptive traits

ABSTRACT Indicine and taurine subspecies present distinct morphological traits as a consequence of environmental adaptation and artificial selection. Although the two subspecies have been characterized and compared at genome-wide level and at specific loci, their epigenetic diversity has not yet been explored. In this work, Reduced Representation Bisulphite Sequencing (RRBS) profiling of the taurine Angus (A) and indicine Nellore (N) cattle breeds was applied to identify methylation differences between the two subspecies. Genotyping by sequencing (GBS) of the same animals was performed to detect single nucleotide polymorphisms (SNPs) at cytosines in CpG dinucleotides and remove them from the differential methylation analysis. A total of 660,845 methylated cytosines were identified within the CpG context (CpGs) across the 10 animals sequenced (5 N and 5 A). A total of 25,765 of these were differentially methylated (DMCs). Most DMCs clustered in CpG stretches nearby genes involved in cellular and anatomical structure morphogenesis. Also, sequences flanking DMC were enriched in SNPs compared to all other CpGs, either methylated or unmethylated in the two subspecies. Our data suggest a contribution of epigenetics to the regulation and divergence of anatomical morphogenesis in the two subspecies relevant for cattle evolution and sub-species differentiation and adaptation.

Cattle tick and gastrointestinal nematodes strategic control in dairy 31/32 Gyr x Holstein and beef ½ Brangus: is the same way?

Cattle ticks and gastrointestinal nematodes (GINs) are a major concern in cattle rearing. Strategic treatments with chemical products are used to curb these infestations and infections. There are several studies on the population dynamics and strategic control of these parasites; however, none considered the genetic proportion of dairy cattle (Bos taurus taurus) and beef cattle (crossbred) to establish and understand the best strategy to control these parasites. To establish and understand the best strategy to control these parasites, we evaluated strategic treatment schemes against cattle ticks and GINs in dairy (Bos taurus taurus-Gyr × Holstein, 31/32) and beef (crossbred-1/2 Nellore × 1/2 Angus) cattle with different genetics. To determine whether the adopted strategic control scheme was sufficient to maintain a low level of infestation or infection of cattle ticks and GINs in animals, a group of dairy and crossbred beef cattle received chemical treatment only as a palliative treatment. Concomitantly, the productive and reproductive data of the animals were evaluated. The results showed that the level of challenge by ticks was different in crossbred beef (½ Nellore × ½ Angus) and dairy (Gyr × Holstein 31/32) cattle, and it was necessary to adopt different protocols for strategic or palliative treatments in these animals. Eight palliative treatments against Rhipicephalus microplus for over 12 months were necessary for dairy cattle, while only one was necessary for crossbred beef cattle. Thus, a more suppressive strategic protocol should be established in dairy cattle for monitoring the tick burden because new treatments may be necessary depending on the situation. In contrast, in crossbred beef cattle, an endectocide could be used after weaning, and other treatments must be conditioned to the presence of ticks in cattle. Further, prolonged periods without chemical treatment can increase the proportion of GINs, such as Haemonchus spp., compared to Cooperia spp. in these animals. Therefore, two to three treatments per year, depending on the anthelmintic used, are recommended for dairy and beef cattle. In both dairy and beef cattle, the strategic treatments showed better weight gain at the end of the study, resulting in greater productivity and return on investment (ROI), in crossbred beef cattle. Reproductive parameters were numerically similar in dairy females subjected to different treatment regimens.

Polymorphism detection of PRKG2 gene and its association with the number of thoracolumbar vertebrae and carcass traits in Dezhou donkey

BackgroundPrevious studies have shown that the protein kinase cGMP-dependent 2 (PRKG2) gene is associated with dwarfism in humans, dogo Argentines, and Angus cattle, as well as with height and osteoblastogenesis in humans. Therefore, the PRKG2 gene was used as the target gene to explore whether this gene is associated with several thoracolumbar vertebrae and carcass traits in Dezhou donkeys.ResultsIn this study, fifteen SNPs were identified by targeted sequencing, all of which were located in introns of the PRKG2 gene. Association analysis illustrated that the g.162153251 G > A, g.162156524 C > T, g.162158453 C > T and, g.162163775 T > G were significantly different from carcass weight. g.162166224 G > A, g.162166654 T > A, g.162167165 C > A, g.162167314 A > C and, g.162172653 G > C were significantly associated with the number of thoracic vertebrae. g.162140112 A > G was significantly associated with the number and the length of lumbar vertebrae, and g.162163775 T > G was significantly associated with the total number of thoracolumbar vertebrae.ConclusionOverall, the results of this study suggest that PRKG2 gene polymorphism can be used as a molecular marker to breed high-quality Dezhou donkeys.

In utero choline exposure alters growth, metabolism, feed efficiency, and carcass characteristics of Holstein x Angus cattle from weaning to slaughter.

Feeding rumen protected choline (RPC) to late gestation dairy cows has potential to affect growth in offspring. The objective of this study was to evaluate the effects of in utero choline exposure on the growth, feed efficiency (FE), metabolism, and carcass quality of Angus x Holstein cattle. Multiparous Holstein cows pregnant with male (n=17) or female (n=30) Angus-sired calves were enrolled 21 d prepartum and randomly assigned to one of four dietary treatments varying in quantity and formulation of rumen-protected choline (RPC). The treatments included a control with 0g/d supplemental RPC (CTL), supplemental RPC fed at the recommended dose (RD) of 15g/d from either an established RPC product (RPC1RD; ReaShure; Balchem Corp) or choline ion from a concentrated RPC prototype (RPC2RD; Balchem Corp), or a high dose (HD) of RPC2 fed at 22g/d (RPC2HD). From 2 to 6 mo of age, calves were group housed and offered 2.3kg grain/hd/d (42% CP) with ad libitum grass hay, and stepped up to a complete finishing diet by 7 mo (12.0% CP; 1.34 Mcal/kg NEg). Weight and height were measured monthly. Animal FE was measured in individual pens for 35 d at 8 mo. Feed intake was measured daily, and blood was obtained on d 18 during the FE period. Afterwards, cattle were group housed and offered a free-choice finishing diet until slaughter, where carcass yield and quality characteristics were measured. Mixed models were used in PROC MIXED (SAS, 9.4) with the fixed effects of treatment, sex, time, their interactions, and the random effect of calf. Month was the repeated measure, and preplanned contrasts were used. Blood and FE data were analyzed with the fixed effect of dam choline treatment, calf sex, and the interaction. Increasing dose of RPC tended to increase weight over the entire study period. Feeding any RPC increased hip and wither height compared with CTL, and increasing RPC dose linearly increased hip and wither height. Treatment and sex interacted on DMI whereby increasing RPC intake linearly increased DMI for males but not females. Compared with control, feeding any RPC decreased plasma insulin, glucose, and an insulin sensitivity index (RQUICKI). In utero choline exposure increased kidney-pelvic-heart fat and marbling score. Mechanisms of action for intrauterine choline exposure on offspring growth, metabolism, and carcass characteristics should be explored as they have direct implications for profitability for cattle growers and feeders.

Genetic parameters for pulmonary arterial pressure, yearling performance, and carcass ultrasound traits in Angus cattle.

Pulmonary arterial pressure (PAP) can be used as an indicator of susceptibility to pulmonary hypertension and subsequent potential to develop right-sided heart failure (RHF). Previously reported heritability estimates of PAP have been moderate to high. Based on these estimates, selection for the indicator trait, PAP, could reduce the incidence of RHF due to hypoxia. Previous studies have also speculated that increased growth rates and body fat accumulation contribute to increased PAP and RHF. Research evaluating the genetic relationships between PAP and performance traits (e.g., yearling weight and postweaning gain) has yielded conflicting results, leading to ambiguity and uncertainty regarding the underlying genetic relationships. Additionally, no previous research has evaluated the relationship between PAP and ultrasound carcass traits. Therefore, the objective of this study was to estimate trait heritabilities and genetic correlations between PAP, post-weaning growth traits, and ultrasound carcass traits in Angus cattle, using data (n = 4,511) from the American Angus Association. We hypothesized that traits associated with increased growth and muscle would have a positive genetic (i.e., unfavorable) relationship with PAP. Estimates for heritability and genetic correlations were obtained using a multi-trait animal model. Heritability estimates for PAP (0.21 ± 0.04), post-weaning gain (PWG; 0.31 ± 0.04), and yearling weight (YWT; 0.37 ± 0.04) were within the range of estimates previously reported. Genetic correlations were weak (< 0.20) between PAP, PWG, and YWT. A low-to-moderate genetic correlation between PAP and ultrasound ribeye area (UREA) was found (0.25 ± 0.12). Genetic correlations between PAP, ultrasound back fat (UBF), ultrasound intramuscular fat (IMF), and ultrasound rump fat (RUMP) were weak (ranging in magnitude from -0.05 to 0.10) and therefore, do not provide strong support for the hypothesis of an antagonistic relationship between PAP and carcass ultrasound traits, while heritability estimates for UBF (0.43 ± 0.05), UREA (0.31 ± 0.04), IMF (0.35 ± 0.04), and RUMP (0.47 ± 0.05) were in the range of previously reported values.

Temperature Fluctuations Modulate Molecular Mechanisms in Skeletal Muscle and Influence Growth Potential in Beef Steers.

Our investigation elucidated the effects of severe temperature fluctuations on cellular and physiological responses in beef cattle. Eighteen Red Angus beef steers with an average body weight of 351 ± 24.5 kg were divided into three treatment groups: 1) Control (CON), exposed to a temperature-humidity index (THI) of 42 for 6 h without any temperature changes; 2) Transport (TP), subjected to a one-mile trailer trip with a THI of 42 for 6 h; and 3) Temperature swing (TS), exposed to a one-mile trailer trip with a THI shift from 42 to 72-75 for 3 h. Our findings indicate that TS can induce thermal stress in cattle, regardless of whether the overall temperature level is excessively high or not. Behavioral indications of extreme heat stress in the cattle were observed, including extended tongue protrusion, reduced appetite, excessive salivation, and increased respiratory rate. Furthermore, we observed a pronounced overexpression (P < 0.05) of heat shock proteins (HSPs) 20, 27, and 90 in response to the TS treatment in the longissimus muscle (LM). Alterations in signaling pathways associated with skeletal muscle growth were noted, including the upregulation (P < 0.01) of Pax7, Myf5, and myosin heavy chain (MHC) isoforms. In addition, an increase (P < 0.05) in transcription factors associated with adipogenesis was detected (P < 0.05), such as PPARγ, C/EBPα, FAS, and SCD in the TS group, suggesting the potential for adipose tissue accumulation due to temperature fluctuations. Our data illustrated the potential impacts of these temperature fluctuations on the growth of skeletal muscle and adipose tissue in beef cattle.

Selection for yearling growth rate in Angus cattle results in bigger cows that eat more

Context Measurement of weight provides the basis of most performance-recording schemes for beef cattle around the world. The limitation of faster growth rate as a breeding objective, without considering changes in mature-cow weight, is the expected increase in cow size and, hence, feed requirements. Aims To measure the correlated changes in feed intake and efficiency of cows, calves and the cow–calf unit following divergent selection for growth rate. Methods The cows and their calves came from three lines of Angus cattle selected for either fast weight gain to yearling age (the High-line), slow weight gain (the Low-line), or from an unselected Control-line. Efficiency was evaluated over an annual production cycle. Individual cow weights and feed intakes, and calf growth and feed intake (including milk), were recorded. Milk production, milk composition and body composition were also measured so that correlated changes in efficiency of use of energy and nitrogen could be determined. Key results The High-line cows were 18% (P &lt; 0.05) heavier than the Low-line cows at the start and consumed 7% (P &lt; 0.05) more feed than did the Low-line cows. Feed efficiency of the cow–calf unit was 12% higher (P &lt; 0.05) in the High-line cows and calves than in the Low-line cows and calves. When compared on the basis of feed used relative to their weight and weight gain there was no difference (P &gt; 0.05) between the selection lines. Divergent selection was accompanied by a change in body composition, with the High-line cows containing proportionally less protein and more fat in their bodies than did the Low-line cows. There was no evidence for change in the efficiency of feed energy use, but there was a 10% (P &lt; 0.05) improvement in nitrogen efficiency of the cow–calf unit in the High-line compared with the Low-line. Conclusions Divergent selection for weight gain led to a correlated change in cow size and cow feed requirements. Implications This experiment supported the consensus among earlier reviews that there is little evidence that selection for growth rate or size, without moderating change in mature-cow weight, is associated with improved efficiency of feed energy use in maternal beef breeds.

Emissão de óxido nitroso de excretas de diferentes raças de gado de corte terminados em confinamento

Abstract The objective of this work was to compare nitrous oxide (N2O) emissions from urine and manure of Nellore and crossbred (Nellore x Angus) cattle finished in feedlot. Twenty Nellore and 20 crossbred bulls were fed a diet consisting of 75% concentrate and 25% roughage. Excreta were applied to the pens after 43 days of confinement, when N2O monitoring started through static chambers. The data were subjected to the analysis of variance, and averages were compared by Tukey’s test. The N2O fluxes from urine and manure were similar among the breeds, with important peaks after rain events. The cumulative emissions of N2O from urine per kilogram of body weight gain (BWG) and the total emissions from manure per kilogram of BWG were 22.7% and 24.4% higher in Nellore cattle. There is no breed effect on N2O flux and cumulative emissions by excreta from confined beef cattle; however, the crossbreed emits less per kilogram of BWG. There is a high correlation between rainfall volume and the N2O emissions of the next day, which indicates a period between rain occurrence and the increase in N2O emission.

Approximating prediction error variances and accuracies of estimated breeding values from a SNP–BLUP model for genotyped individuals

Context The accuracy of estimated breeding values (EBVs) is an important metric in genetic evaluation systems in Australia. With reduced costs for DNA genotyping due to advances in molecular technology, more and more animals have been genotyped for EBVs. The rapid increase in genotyped animals has grown beyond the capacity of the current genomic best linear unbiased prediction (GBLUP) method. Aims This study aimed to implement and evaluate a new single-nucleotide polymorphism (SNP)–BLUP model for the computation of prediction error variances (PEVs) to accommodate the increasing number of genotyped animals in beef and sheep single-step genetic evaluations in Australia. Methods First, the equivalence of PEV estimates obtained from both GBLUP and SNP-BLUP models was demonstrated. Second, the computing resources required by each model were compared. Third, within the SNP-BLUP model, the PEVs obtained from subsets of SNP were evaluated against those from the complete dataset. Fourth, the new model was tested in the Australian Merino sheep and Angus beef cattle datasets. Key results The PEVs of genotyped animals calculated from the SNP–BLUP model were equivalent to the PEVs derived from the GBLUP model. The SNP–BLUP model used much less time than did the GBLUP model when the number of genotyped animals was larger than the number of SNPs. Within the SNP–BLUP model, the running time could be further reduced using a subset of SNPs makers, with high correlations (&gt;0.97) observed between the PEVs obtained from the complete dataset and subsets. However, it is important to exercise caution when selecting the size of the subsets in the SNP–BLUP model, as reducing the subset size may result in an increase in the bias of the PEVs. Conclusions The new SNP-BLUP model for PEV calculation for genotyped animals outperforms the current GBLUP model. A new accuracy program has been developed for the Australian genetic evaluation system which uses much less memory and time to compute accuracies. Implications The new model has been implemented in routine sheep and beef genetic evaluation systems in Australia. This development ensures that the calculation of accuracies is sustainable, with increasing numbers of animals with genotypes.

Influence of dietary neutral detergent fiber on feed intake and nutrient digestibility of crossbred Black Angus cattle

Influence of dietary neutral detergent fiber on feed intake and nutrient digestibility of crossbred Black Angus cattle

Differences in meat quality between Angus cattle and Xinjiang brown cattle in association with gut microbiota and its lipid metabolism.

Gut microbiota plays important roles in mediating fat metabolic events in humans and animals. However, the differences of meat quality traits related to the lipid metabolism (MQT-LM) in association with gut microbiota involving in lipid metabolism have not been well explored between Angus cattle (AG) and Xinjiang brown cattle (BC). Ten heads of 18-month-old uncastrated male AG and BC (5 in each group) raised under the identical conditions were selected to test MQT-LM, i.e., the backfat thickness (BFT), the intramuscular fat (IMF) content, the intramuscular adipocyte areas (IAA), the eye muscle area (EMA), the muscle fiber sectional area (MFSA) and the muscle shear force after sacrifice. The gut microbiota composition and structure with its metabolic function were analyzed by means of metagenomics and metabolomics with rectal feces. The correlation of MQT-LM with the gut microbiota and its metabolites was analyzed. In comparison with AG, BC had significant lower EMA, IMF content and IAA but higher BFT and MFSA. Chao1 and ACE indexes of α-diversity were lower. β-diversity between AG and BC were significantly different. The relative abundance of Bacteroidetes, Prevotella and Blautia and Prevotella copri, Blautia wexlerae, and Ruminococcus gnavus was lower. The lipid metabolism related metabolites, i.e., succinate, oxoglutaric acid, L-aspartic acid and L-glutamic acid were lower, while GABA, L-asparagine and fumaric acid were higher. IMF was positively correlated with Prevotella copri, Blautia wexlerae and Ruminococcus gnavus, and the metabolites succinate, oxoglutaric acid, L-aspartic acid and L-glutamic acid, while negatively with GABA, L-asparagine and fumaric acid. BFT was negatively correlated with Blautia wexlerae and the metabolites succinate, L-aspartic acid and L-glutamic acid, while positively with GABA, L-asparagine and fumaric acid. Prevotella Copri, Blautia wexlerae, and Ruminococcus gnavus was all positively correlated with succinate, oxoglutaric acid, while negatively with L-asparagine and fumaric acid. In conclusion, Prevotella copri, Prevotella intermedia, Blautia wexlerae, and Ruminococcus gnavus may serve as the potential differentiated bacterial species in association with MQT-LM via their metabolites of oxoglutaric acid, succinate, fumaric acid, L-aspartic acid, L-asparagine, L-glutamic acid and GABA between BC and AG.

IDENTIFICATION OF THE GENETIC DEFECT OF DEVELOPMENTAL&#x0D; DUPLICATION (DD) IN THE BELARUSIAN POPULATION OF&#x0D; ABERDEEN ANGUS CATTLE

Developmental duplication (DD) is a monogenic autosomal recessive disease with incomplete penetrance and variable&#x0D; expressivity of Aberdeen Angus cattle, resulting in calves with twice the number of various organs and limbs of the animal. According to the literature, the frequency of mutations that cause developmental duplications in Aberdeen is high (above 20%). Single nucleotide polymorphism (SNP) g.34618072T &gt; C in the NHLRC2 gene, which causes developmental duplication, was studied by PCR-RFLP. We screened a sample from the Belarusian population of Aberdeen-Angus cattle (n = 170 heads), which did not reveal animals carrying the mutant allele (DDC) both among the studied cows and among bulls.

Rumen Microbial Predictors for Short-Chain Fatty Acid Levels and the Grass-Fed Regimen in Angus Cattle.

The health benefits of grass-fed beef are well documented. However, the rumen microbiome features in beef steers raised in a grass-fed regimen have yet to be identified. This study examined the rumen microbiome profile in the feeding regimes. Our findings show that the rumen microbiome of the grass-fed cattle demonstrated greater species diversity and harbored significantly higher microbial alpha diversity, including multiple species richness and evenness indices, than the grain-fed cattle. Global network analysis unveiled that grass-fed cattle's rumen microbial interaction networks had higher modularity, suggesting a more resilient and stable microbial community under this feeding regimen. Using the analysis of compositions of microbiomes with a bias correction (ANCOM-BC) algorithm, the abundance of multiple unclassified genera, such as those belonging to Planctomycetes, LD1-PB3, SR1, Lachnospira, and Sutterella, were significantly enriched in the rumen of grass-fed steers. Sutterella was also the critical genus able to distinguish the two feeding regimens by Random Forest. A rumen microbial predictor consisting of an unclassified genus in the candidate division SR1 (numerator) and an unclassified genus in the order Bacteroidales (denominator) accurately distinguished the two feeding schemes. Multiple microbial signatures or balances strongly correlated with various levels of SCFA in the rumen. For example, a balance represented by the log abundance ratio of Sutterella to Desulfovibrio was strongly associated with acetate-to-propionate proportions in the rumen (R2 = 0.87), which could be developed as a valuable biomarker for optimizing milk fat yield and cattle growth. Therefore, our findings provided novel insights into microbial interactions in the rumen under different feed schemes and their ecophysiological implications. These findings will help to develop rumen manipulation strategies to improve feed conversion ratios and average daily weight gains for grass- or pasture-fed cattle production.