Bonsmara Research Articles

Runs of Homozygosity and Quantitative Trait Locus/Association for Semen Parameters in Selected Chinese and South African Beef Cattle.

Simple SummaryGenome-wide runs of homozygosity (ROH) are excellent in understanding population history, estimating genomic inbreeding, and deciphering genetic architecture of complex traits and diseases, as well as identifying genes of agro-economic traits. ROH are defined as continuous region on the chromosome where an individual is homozygous across the genome. This study identified distribution of ROH in the six selected beef cattle breeds, Chinese Simentaler (CSI), Belgian Blue (BEL), and South African Angus (ANG), Nguni (NGU), Bonsmara (BON), and Simentaler (SIM), using Bovine BeadChip markers. Furthermore, nine candidate genes, CDF9, MARCH1, WDR19, SLOICI, ST7, DOP1B, CFAF9, INHBA, and ADAMTS1, were suggested to be associated with semen QTL traits and reported moderate inbreeding in some breeds with high to low correlation inbreeding between breeds. The study findings will allow proper guidelines for breeder’s societies.In this study, runs of homozygosity (ROH) and quantitative trait locus/association (QTL) for semen parameters in selected Chinese and South African beef cattle breed were estimated. The computed results showed 7516 ROH were observed between classes 0–5 Mb with no ROH observed in classes >40 Mb. Distribution of ROH showed high level of genomic coverage for ANG, NGU, CSI, and BEL breeds. Approximately 13 genomic regions with QTL were controlling sperm motility, sperm concentration, semen volume, sperm count, sperm head abnormalities, sperm tail abnormalities, sperm integrity, and percentage of abnormal sperm traits. Nine candidate genes, CDF9, MARCH1, WDR19, SLOICI, ST7, DOP1B, CFAF9, INHBA, and ADAMTS1, were suggested to be associated with above mentioned QTL traits. The results for inbreeding coefficient showed moderate correlation between FROH vs FHOM at 0.603 and high correlation between FROH 0–5 Mb 0.929, and lowest correlation for 0–>40 Mb 0.400. This study suggested recent inbreeding in CSI, BEL, ANG, BON, SIM, and NGU breeds. Furthermore, it highlighted varied inbreeding levels and identified QTL for semen traits and genes of association. These results can assist in implementation of genetic improvement strategies for bulls and provide awareness and proper guidelines in developing breeding programs.

Evaluation of the International Society forAnimal Genetics bovine single nucleotide polymorphism parentage panel in South African Bonsmara and Drakensberger cattle.

A panel of 200 single nucleotide polymorphisms (SNPs) have been recommended by the International Society for Animal Genetics (ISAG) for use in parentage verification of cattle. While the SNPs included on the ISAG panel are segregating in European Bos taurus and Bos indicus breeds, their applicability in South African (SA) Sanga cattle has never been evaluated. This study, therefore, assessed the usefulness of the ISAG panel in SA Bonsmara (BON) and Drakensberger (DRB) cattle. Genotypes of 185 ISAG SNPs from 64 BON and 97 DRB sire-offspring pairs were available, all of which were validated with 119,375 SNPs. Of the 185 ISAG SNPs, 14 and 18 in the BON and DRB, respectively (9 in common to both breeds), were either monomorphic, exhibited at least one discordance between validated sire-offspring pairs, or had poor call rate or clustering issue. The mean minor allele frequency of the 185 ISAG SNPs was 0.331 in the BON and 0.359 in the DRB. The combined probability of parentage exclusion (PE) was the same (99.46%) for both breeds, while the probability of identity varied from 1.61 × 10-48 (BON) to 1.11 × 10-54 (DRB). Fifteen (23.4%) and 32 (33%) of the already validated sire-offspring pairs for the BON and DRB, respectively, were determined by the ISAG panel to be false-negatives based on a threshold of having at least two discordant SNPs. In comparison to sire discovery using the 119,375 SNPs, sire discovery using only the ISAG panel identified correctly 44 (out of 64 identified using the 119,375 SNPs) unique sire-offspring BON pairs and 62 (out of 97 identified using the 119,375 SNPs) unique sire-offspring DRB when all sires were masked. Five BON and three DRB offspring had > 1 sire nominated. This study demonstrated that the use of the ISAG panel may result in incorrect exclusions and multiple candidate sires for a given animal. Selection of more informative SNPs is, therefore, necessary in the pursuit of a low-cost and effective SNP panel for indigenous cattle breeds in SA.

Effects of sodium selenite and chromium sulphate as metabolic modifiers on stress alleviation, performance and liver mineral contents of feedlot Bonsmara cross steers

The objective of the study was to investigate the effects of supplemental selenium and chromium on blood cortisol and glucose levels on stress alleviation and the carry-over effects on performance and liver mineral contents of local beef cattle under feedlot conditions. Seventy-two Bonsmara cross weaned calves weighing on average 185 ± 20.729 kg were allocated to 12 pens of six animals each, three replicates per treatment and fed for 120 days either a standard diet (CON) or supplemented with 0.3 mg.kg –1 DM sodium selenite (SEL) 0.3 mg.kg –1 DM chromium sulphate (CHR) and a combination of Se and Cr (SEL/CHR). Blood cortisol and glucose levels as stress parameters, feed intake and growth performance parameters were assessed. There was no statistical difference in blood cortisol levels on d0. On d14, cortisol concentrations were lower than on d0 (P<0.05) except for treatment SEL/CHR. On d42, the values were higher than on d0 and d14 except for SEL/CHR that had very low cortisol values (P<0.05). Blood glucose concentrations followed similar trend. There was no carry-over effect of stress alleviation on growth performance though SEL/CHR tended to have better ADG (P=0,148) and predicted FCR (P=0,197). Liver tissue mineral levels were within normal ranges. However, SEL increased significantly (P<0.05) liver Ca, Mg, Co and Mn while CHR decreased Ca and Mg concentrations. Selenium was positively correlated with Cu (r=0.30, P= 0.01) and phosphorus (r=0.44, P=0.0001) while Cr was negatively correlated with Ca (r=-0.50, P=0.01) and Mg (r=-0.30, P=0.01). Liver tissue minerals did not affect performance parameters. SEL/CHR might act better on stress alleviation and growth improvement. The effects on carcass characteristics and meat quality and the use of different forms of supplemental Se and Cr warrant further research. Key words: Selenium, chromium, stress, cortisol, glucose, feedlot, Bonsmara.

Características de carcaça e qualidade da carne de bovinos de corte de quatro grupos genéticos terminados em confinamento

Este trabalho foi realizado com o objetivo de avaliar as características de carcaça e a qualidade da carne de animais puros das raças Tabapuã, Bonsmara e mestiços ½ Bonsmara + ½ Nelore e mestiços ½ Bonsmara + ¼ Red Angus + ¼ Nelore. Foram utilizados cinco bovinos castrados de cada grupo genético, com idade média de 22 meses e peso vivo de 394±21 kg ao início do experimento. A dieta, para todos os animais, continha silagem de cana-de-açúcar e ração comercial na proporção de 55% e 45% (base seca), respectivamente, com 14,99% de proteína bruta (PB) e 59,84% de nutrientes totais digestíveis (NDT). Ao abate, não foram observadas diferenças no peso de carcaça fria nem nos pesos e percentuais dos cortes comerciais (traseiro, costilhar e dianteiro) entre os grupos genéticos. Os animais puros Bonsmara apresentaram maior área de olho-de-lombo, maior percentual de músculo e menor percentual de gordura na carcaça. Nos animais mestiços ½ Bonsmara + ½ Nelore, a espessura de gordura de cobertura (EGC) foi maior que os Bonsmara e Tabapuã, porém todos os grupos genéticos apresentaram EGC acima do mínimo (3 mm) exigido pelos frigoríficos. Não foi observada diferença na composição centesimal da carne entre os grupos genéticos. A carne dos animais Bonsmara e mestiços ½ Bonsmara + ½ Nelore e ½ Bonsmara + ¼ Red Angus + ¼ Nelore foi mais macia que a dos animais Tabapuã. O perfil de ácidos graxos no músculo longissimus dorsi não diferiu entre os grupos genéticos estudados. A carne dos animais Bonsmara e mestiços ½ Bonsmara + ½ Nelore e ½ Bonsmara + ¼ Red Angus + ¼ Nelore apresentou melhor qualidade se comparada à dos Tabapuã.

Characterization of biological types of cattle (Cycle VIII): Carcass, yield, and longissimus palatability traits12

The objective of this experiment was to evaluate alternative sources of tropically adapted cattle germplasm and compare them with Angus- (AN) and Hereford- (HE) sired steers. Carcass, yield, and longissimus thoracis palatability traits from F(1) steers (n = 621) obtained from mating AN and MARC III cows to HE, AN, Brangus (BR), Beefmaster (BM), Bonsmara (BO), or Romosinuano (RO) sires were compared. Data were adjusted to constant age (426 d), carcass weight (340 kg), fat thickness (1.0 cm), fat trim percentage (25%), and marbling (Small(00)) endpoints. For Warner-Bratzler and slice shear force and trained and untrained sensory panel traits, data were obtained on LM from ribeye steaks stored at 2 degrees C for 14 or 15 d postmortem. The following comparisons were from the age-constant endpoint. Carcasses from BM-, AN-, and BR-sired steers (358, 355, and 351 kg, respectively) were heavier (P < 0.05) than carcasses from steers from HE (343 kg) and BO (331 kg) sires; RO-sired steers (318 kg) had the lightest (P < 0.05) carcasses. Adjusted fat thicknesses for AN- and BM-sired steers (1.3 and 1.2 cm, respectively) were greater (P < 0.05) than for steers from BR (1.0 cm) and BO (0.9 cm) sires; RO-sired steers (0.8 cm) had the least fat thickness. Longissimus areas were larger (P < 0.05) for BO- and BR-sired steers (84.4 and 84.1 cm(2), respectively) than for BM- and HE-sired steers (80.8 and 80.2 cm(2), respectively). A greater (P < 0.05) percentage of carcasses from AN-sired steers graded USDA Choice (69%) than other sire breeds (17 to 47%) except HE (52%). Carcass yield of boneless, totally trimmed retail product was least (P < 0.05) for AN-sired steers (60.1%) and greatest (P < 0.05) for RO- and BO-sired steers (64.4 to 63.5%). Considering all measurements, AN LM tended to be more tender and BM LM tended to be least tender. American composite breeds BM and BR were heavier, fatter, lesser yielding, with similar marbling scores but less tender LM than BO and RO. Angus carcasses were similar in size, fatter, lesser yielding, with more marbling and more tender LM compared with BM and BR. Bonsmara and RO provide tropically adapted germplasm and produce carcasses that are lighter, leaner, greater yielding, with similar marbling and LM that tend to be more tender than carcasses from BM and BR.

A comparison of stress hormone concentrations at slaughter in Nguni, Bonsmara and Angus steers

Concentrations of stress hormones at slaughter were determined in 15 of each of 18-month old Angus, Bonsmara and Nguni steers. The steers were slaughtered at the East London Abattoir, which is about 120 km from the University of Fort Hare farm, where the animals had been raised. Serum creatinine and packed cell volume (PCV) concentrations were determined before cattle transportation. Blood was also collected along the slaughter line immediately after exsanguination for the determination of cortisol, creatinine and PCV. Urine samples were collected for the measurement of creatinine, adrenaline, noradrenaline and dopamine concentrations. Estimated glomerular filtration rate was also determined. Bonsmara had the highest concentrations of adrenaline (10.8 nmol/mol), noradrenaline (9.7 nmol/mol) and dopamine (14.8 nmol/mol) concentrations, whereas the Nguni had the least concentrations of adrenaline (6.5 nmol/mol), noradrenaline (4.6 nmol/mol) and dopamine (4 nmol/mol) concentrations. The Nguni had the highest serum cortisol concentrations (2.3 nmol/mol), while Angus had the least concentrations (1.3 nmol/mol). There were no (P > 0.05) breed differences in serum and urea creatinine concentrations, and on estimated glomerular filtration rate (eGFR). Bonsmara steers had higher (P < 0.05) levels of catecholamines and dopamine compared to Nguni and Angus steers after transport and handling stress. The Bonsmara was therefore the most stress responsive breed at slaughter. Key words: Stress, cortisol, dopamine, adrenaline, animal welfare, breed.