Angus Breed Research Articles

Vpliv SNP znotraj FTO in LEP gena na prirast telesne mase pri govedu

Body mass gain in a certain time period is one of the most important parameters in beef production. Some candidate genes, which have major impact on growth traits, are known from the literature, notably among them the FTO (fat mass and obesity-associated) and LEP (leptin) locus. In our experiment, we assessed the frequency of alleles at two polymorphic sites within the FTO gene (FTO6 and FTO10) and at polymorphic site in the LEP gene in a sample of Aberdeen Angus (AA) and Holstein Friesian (HF) breeds. In a larger sample, containing dairy and beef cattle breeds we tested the association of these three SNPs with the body mass gain in a 200-day period (between 165th and 365th day of age). In our material we could not confirm the linkage between two SNPs within the FTO locus, due to the existence of the region with high recombination rate between exon 5 and intron 5 in the FTO gene. We demonstrated significant impact of birth weight, breed and SNPs in the FTO gene on the growth. The effect of the polymorphic site within the LEP gene could not be confirmed.

Polymorphisms in the Prion Protein Gene of cattle breeds from Brazil

ABSTRACT: One of the alterations that occur in the PRNP gene in bovines is the insertion/deletion (indel) of base sequences in specific regions, such as indels of 12-base pairs (bp) in intron 1 and of 23- bp in the promoter region. The deletion allele of 23 bp is associated with susceptibility to bovine spongiform encephalopathy (BSE) as well as the presence of the deletion allele of 12 bp. In the present study, the variability of nucleotides in the promoter region and intron 1 of the PRNP gene was genotyped for the Angus, Canchim, Nellore and Simmental bovine breeds to identify the genotype profiles of resistance and/or susceptibility to BSE in each animal. Genomic DNA was extracted for amplification of the target regions of the PRNP gene using polymerase chain reaction (PCR) and specific primers. The PCR products were submitted to electrophoresis in agarose gel 3% and sequencing for genotyping. With the exception of the Angus breed, most breeds exhibited a higher frequency of deletion alleles for 12 bp and 23 bp in comparison to their respective insertion alleles for both regions. These results represent an important contribution to understanding the formation process of the Brazilian herd in relation to bovine PRNP gene polymorphisms.

Characterization of the Russian beef cattle breed gene pools using inter simple sequence repeat DNA analysis (ISSR analysis)

The gene pools of beef cattle breeds bred in Russia were characterized on the basis of inter simple sequence repeat DNA analysis (ISSR analysis). Samples of Aberdeen Angus, Kalmyk, and Kazakh Whitehead breeds from Russia, as well as of Hereford breed, hybrids of Kazakh Whitehead and Hereford breeds, and Kazakh Whitehead breed from the Republic of Kazakhstan, were examined. In the examined breeds, 27 AG-ISSR fragments were identified, 25 of which were polymorphic. The examined breeds were different both in the fragment profiles (the presence/absence of individual ISSR fragments) and in their frequencies. It was demonstrated that the hybrid animals lacked some ISSR fragments that were present with high frequencies in parental forms, suggesting considerable genome rearrangement in the hybrid animals (at the regions of microsatellite localization) in crossings of the individuals from different breeds. The level of genetic diversity in Russian beef breeds was consistent with the values typical of farmed populations (breeds). The genetic diversity parameters assessed by applying Nei’s gene diversity index and the Shannon index varied from 0.0218 to 0.0605 and from 0.0225 to 0.0819, respectively. The highest Shannon index value was detected in the Kalmyk breed (0.0837) and Kazakh Whitehead breed from Russia (0.0819), and the highest level of Nei’s gene diversity index was found in the Kalmyk breed (0.0562) and in both populations of the Kazakh Whitehead breed (0.0509 and 0.0605). The high level of genetic similarity (according to Nei) was revealed between Russian beef cattle breeds and Hereford cattle: 0.839 (for the Kazakh Whitehead breed from Russia) and 0.769 (for the Kalmyk breed).

Performance, carcass characteristics, and ruminal pH of Nellore and Angus young bulls fed a whole shelled corn diet.

The objectives of this study were to test the interaction of breed (Nellore or Angus) and diet (whole shelled corn [WSC] or ground corn [GC] with silage) on growth performance, carcass characteristics, and ruminal pH of young bulls. Thirty-six bulls (18 Nellore and 18 Angus) with the range in age of 18 to 22 mo and BW of 381 ± 12 kg were used in a completely randomized design experiment with a 2 × 2 factorial arrangement of treatments (2 breeds and 2 diets). Experimental diets (DM basis) included 1) a GC diet containing 30% corn silage and 70% GC- and soybean meal-based concentrate and 2) a WSC diet containing 85% WSC and 15% of a soybean meal- and mineral-based pelleted supplement. An additional 8 bulls were slaughtered at the beginning of the experimental period for determination of initial carcass weight. The treatments were Nellore fed the GC diet, Nellore fed the WSC diet, Angus fed the GC diet, and Angus fed the WSC diet. Greater DMI ( < 0.01), ADG ( < 0.01), and G:F ( < 0.01) were observed in Angus bulls compared with Nellore bulls, regardless of diet. Lower average ruminal pH ( = 0.04), maximum ruminal pH (P = 0.02), and DMI ( < 0.01) were observed in bulls fed the WSC diet than in those fed the GC diet. In addition, bulls fed the WSC diet had greater G:F ( < 0.01). The WSC diet led to greater variation in DMI compared with the GC diet ( < 0.01). Omasum and large intestine percentage was affected by diets only in the Angus breed ( < 0.02) and were greater when bulls were fed the GC diet. The WSC diet without forage may be useful for feedlots because this diet promoted greater G:F than the GC diet, regardless of breed. However, special care must be exercised in feed management during adaptation and throughout the feeding of Nellore animals to avoid digestive disorders and fluctuations in DMI.

Transferência de imunidade passiva e proteinograma sérico em bezerros das raças Crioula Lageana variedade Mocha e Aberdeen Angus (Red Angus) nos primeiros seis meses de vida

Resumo: A raça Crioula Lageana apresenta-se como uma alternativa para a pecuária moderna, devido a sua grande variabilidade genética, rusticidade e adaptação às condições ambientais do Planalto Catarinense. Estas características podem influenciar importantes eventos fisiológicos, os quais deveriam ser investigados, pois podem auxiliar no desenvolvimento de futuros programas de melhoramento animal. Sabe-se que a falha da transferência de imunidade passiva (TIP) constitui um importante fator para a elevação dos índices de mortalidade neonatal na espécie bovina. Desta forma, torna-se indispensável à avaliação dos aspectos relacionados à TIP em bezerros da raça Crioula Lageana variedade mocha e a sua comparação com outras raças de corte criadas no Planalto Serrano Catarinense. Com o objetivo de avaliar e comparar a TIP e o proteinograma sérico foram selecionados dois grupos experimentais compostos por 11 bezerros da raça Crioula Lageana variedade mocha e 14 bezerros da raça Aberdeen Angus (Red Angus). Amostras de sangue foram colhidas por meio da venopunção jugular para a mensuração da proteína total sérica (PTS), eletroforese das proteínas séricas em gel de agarose, atividade da gamaglutamiltransferase (GGT) e concentração de imunoglobulinas G (IgG) por meio do método de turvação pelo sulfato de zinco nos períodos entre 24 e 36 horas, 15, 30, 60, 90, 120, 150 e 180 dias de vida. A análise estatística dos dados foi realizada por meio da análise de variância de medidas repetidas (ANOVA), teste de Tukey para a comparação entre médias (P&lt;0,05) e correlação entre as variáveis. Ao analisar os valores de PTS, globulinas, gamaglobulinas, IgG e atividade sérica de GGT ao nascimento (24 a 36 horas) pode se afirmar que houve adequada TIP não havendo diferença significativa entre as raças, exceto para a atividade sérica da GGT. Observaram-se variações fisiológicas na curva de proteínas séricas do nascimento até os 180 dias de idade. Forte correlação positiva foi observada entre os valores de gamaglobulina e IgG (r=0,814 para CL e r=0,877 para AA), PTS (r=0,783 para CL e r=0,947 para AA), globulinas (r=0,945 para CL e r=0,985 para AA), evidenciando que estas variáveis foram bons indicadores da TIP em bezerros ao segundo dia de vida (24-36 horas). A correlação entre gamaglobulinas e atividade da GGT foi fracamente positiva (r=0,251) para bovinos da raça Crioula Lageana variedade mocha e fortemente positiva (r=0,815) para a raça Aberdeen Angus (Red Angus), o qual foi admitido a grande variação nos valores da GGT após 24 horas de vida do bezerro. Não houve diferença na TIP entre as raças Crioula Lageana variedade mocha e Aberdeen Angus (Red Angus), ocorrendo de maneira bem-sucedida em ambas as raças. Pode-se sugerir que a raça Crioula Lageana variedade mocha seja mais tardia na síntese ativa de anticorpos, ressaltando a precocidade dos taurinos evidenciada na raça Aberdeen Angus (Red Angus).

Gastrointestinal Parasites of Cattle in Central Java

Gastrointestinal parasites are the main cause of losses of cattle farms including feed conversion-failure and even death of heavily infected animals. We have conducted a random examination of 455 cows in the Special Region of Yogyakarta-Central Java from March to June 2016. The examined animals were Ongole and Local Cattle (PO) cross breed, Simmental breed, Limousin breed, Simmental and PO cross breed, PO and Limousin cross breed, Friesian Holstein breed (FH), Brahman breed, Angus breed, Angus and Brahman cross breed and Bali breed. McMaster technique, saturated NaCl flotation technique and Parfitt and Banks technique were used simultaneously in this study in order to identify the parasitic stages present in the coprological samples. The test results showed that approximately 65.93% of the cattle population was infected by parasitic stages, such as: Strongylidae (54.00%), Fasciola sp. (17.00%), Eimeria spp. (15.33%), Strongyloides sp. (4.67%), Paramphistomum sp. (4.00%), Trichuris sp. (3.67%) and Moniezia sp. (1.33%). Six different Eimeria species were identified: E. bovis, E. auburnensis, E. bukidnonensis, E. canadaensis, E. zurnii and E. cylindrica. Most of the animals presented monoinfections (79.33%), but concomitant infections were also observed (2 different parasites: 17.67%; 3 different parasites: 2.33%; more than 3 different parasites: 0.67%). With this work we proved the high level of parasitism in cattle of Central Java and we intensively highlight the need to find adequate control measures against parasitic diseases in order to reduce the detrimental impact of parasitosis in cattle.

Hemogram, Fibrinogen Concentration and Plasma Total Protein from Calves of Criollo Lageano Breed Variety Hornless and Aberdeen Angus Breed (Red Angus) on the First Six Months of Life

Background: Neonatal period in bovine presents important variations in hematologic and immunologic parameters, and the resulting mortality rates may be due to increased susceptibility to disease. Race, age, environmental, climate and management factors are sources of CBC’s parameters variation in cattle. The objective of this study is to evaluate and compare the CBC variables and concentrations of total protein (PTP) and plasma fibrinogen calves of Criolo Lageano Breed variety hornless and Aberdeen Angus (Red Angus) in the first six months of life, which are produced under extensive management at the Planalto Serrano Catarinense (southern Brazil).Materials, Methods &amp; Results: Two groups were selected, comprising 11 calves of Hornless Criolo Lageano and 14 calves of the Aberdeen Angus breed (Red Angus). Blood samples were collected for complete blood count and determination of total protein concentrations, and plasma fibrinogen in the periods between 24 h and 36, 15, 30, 60, 90, 120, 150 and 180 days of life. The statistical analysis was performed using analysis of variance for repeated measures (ANOVA) and Tukey’s test (P &lt; 0.05). During the experimental period infestations by ticks in both races were observed. In the first month of life, blood smears revealed the presence of blood parasites of the genus Babesia spp. and Anaplasma sp. The fluctuations seen for erythrocyte in the neonatal period (30 days), although not significant, consisted of raising the number of values of erythrocytes, hemoglobin (Hb) and packed cell volume (PCV), and reduction in mean corpuscular volume values (MCV). From 90 days of age there was a significant reduction in number of red blood cells and VG values, and elevated MCV values and mean corpuscular volume (MCHC) for the Aberdeen Angus (Red Angus). For the WBC, the neonatal period was marked by increase in the number of lymphocytes and decrease in neutrophil ratio: lymphocyte (N, L) with respect to the inversion of 15 days. In the age group 90 days of life was evident increase in the number of leukocytes and lymphocytes in both races. The plasma fibrinogen concentrations showed no significant variations during the trial period. The plasma total protein (PTP), had higher values on the second day of life, with reductions up to 60 days and gradual increase in subsequent times.Discussion: The fluctuations related to the values of erythrocyte variables in the neonatal period are consistent with results reported by other authors in calves of other races. Changes in erythrocyte values observed from 90 days of age on race Aberdeen Angus (Red Angus) can be attributed to infection by blood parasites and consequent hemolysis. As for the leucocyte count, increasing the number of lymphocytes and inversion of N:L is the neonatal period in a physiological variation and confirms observations made by other authors in calves of other races. In the age group 90 days, leukocytosis by lymphocytosis was related to natural premonition against Babesia spp. and Anaplasma spp., which is documented in cattle in tropical and subtropical regions. When analyzing the PTP values on the second day of life, it can be said that there has been proper transfer of passive immunity in both races, given the high correlation of PTP values and gamma globulins. The reduction of PTP and subsequent elevation values are characteristic of the physiological curve related to degradation of passively transferred immunoglobulin and immunoglobulin synthesis by competent immune system.

Effects of SNP within exon 7 of the ınsulin-like growth factor receptor type 1 (IGF1R) gene on growth traits in Angus cows

Insulin-like growth factor 1 receptor (IGF1R) signaling pathway plays a key role in the postnatal growth and development. The tyrosine kinase receptor IGF1R forms homodimers that is activated by IGF-I which trigger autophosphorylation of IGF1R and subsequent downstream signal transduction. The objectives of this study were to identify, characterize and the examination of the association between silent SNP (rs41961336; CaT) within exon 7 of bovine IGF1R gene and growth traits. A total of 672 cows of four breeds was genotyped using the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. A TaiI restriction endonuclease was used. Among all breeds under study (Polish Holstein Friesian, Angus, Hereford, Limousine), the presence of all three genotypes was observed only for the Angus breed. The CC genotype was the most frequent in all investigated breeds (0.7987-0.9904) followed by CT (0.0096-0.1946). Only Angus cows were selected for association analysis. At weaning weight adjusted to 210 days of age (WWT210), statistically significant differences (P≤0.05) were shown female calves with the CC genotype were heavier (+5.5 kg) than the individuals with the CT genotype. However, individuals carrying the CT genotype had significantly higher body weight at first calving (+10.62 kg; P≤0.05). The present work failed to show association between genotypes of the IGF1R/TaiI polymorphism and BWT, ADG or age at first calving.

Growth, carcass and meat quality traits in beef from Angus, Hereford and cross-breed grazing steers, and their association with SNPs in genes related to fat deposition metabolism

Grazing steers from Angus and Hereford breeds, their cross-breeds and a three-way cross-breed (Limousin×Angus–Hereford) were measured for growth, carcass and meat quality traits. Breed effects were studied, and the association of SNPs with fat deposition and fatty acid (FA) composition (leptin, melanocortin-4 receptor, stearoyl-CoA desaturase, FA synthase and thyroglobulin) was tested. Limousin cross-breed showed the greatest final body weight, ultrasound rib eye area, dressing percentage, carcass and leg length, and the lowest backfat thickness and intramuscular fat content. Genetic groups had similar pH, shear force, cooking loss, L* and b* and n-6:n-3 ratio. Meat from 1/2-Angus presented greater a* than Limousin cross-breed. Whereas Angus had the highest total SFA content, Hereford had the lowest total SFA and the highest total MUFA. Limousin cross-breed had greater content of several individual PUFAs, total PUFA, n-6 and n-3 FA than Angus and 1/2-Angus. Leptin and FA synthase were associated with some FAs, supporting their influence over fat metabolism for grazing animals.

Segregación de polimorfismos en μ-calpaina y calpastatina en ganado para carne en Puerto Rico

Se determinó la distribución de polimorfismos de nucleótidos simples (SNP, por sus siglas en inglés) en dos regiones de calpaína (CAPN1- 316 y CAPN1-4751) y una en calpastatina (CAST) en ganado para carne criado en Puerto Rico (n=271). Las frecuencias genotípicas y alélicas se determinaron para cada SNP en las razas Senepol (n=53), Charolais (n=49), Angus (n=27), Charbray (n=38), Brahman (n=16), Cebú (n=16) y toros cruzados (n=72). Para CAPN1-316, las frecuencias genotípicas globales (n=219) fueron 0.07/CC (n=15), 0.38/CG (n=83) y 0.55/GG (n=121) con frecuencias alélicas de 0.26/C y 0.74/G. El genotipo CC estuvo ausente en las razas Charbray, Charolais, Angus, Cebú y Brahman. En toros Charolais, Cebú, Brahman y Charbray el genotipo GG fue mayor que el CG mientras lo inverso fue observado en toros Senepol. En animales Angus y en los cruces, los genotipos CG y GG se encontraron equitativamente distribuidos. Las frecuencias genotípicas globales (n=256) para CAPN1-4751 fueron 0.17/CC (n=44), 0.45/CT (n=114) y 0.38/ TT (n=98). Las frecuencias alélicas fueron 0.39/C y 0.61/T. Animales con el genotipo CT fueron más frecuentes en Charolais, Senepol, Angus y cruces. Los animales TT fueron más comunes en razas Charbray y Brahman. Para CAST, las frecuencias genotípicas globales (n=261) fueron 0.04/CC (n=10), 0.26/CT (n=68), y 0.70/TT (n=183), respectivamente, con frecuencias alélicas de 0.17/C y 0.83/T. No se encontraron animales de genotipo CC en Charolais, Angus y Brahman. El genotipo TT estuvo en mayor proporción en todas las razas y en los animales cruzados. La segregación de polimorfismos en CAPN1 y CAST puede estar implicada en diferencias en características de importancia económica en bovinos para carne criados en Puerto Rico, esta posibilidad debe ser evaluada mediante la genotipificación de un número grande de animales con registros de producción, previo a la incorporación de estos marcadores moleculares en programas de selección genética.

Estimação de parâmetros genéticos de características de crescimento pós desmama de bovinos mestiços Angus X Zebu

The objective of this study was to verify the effect of individual heterozygosity on weights at 365 (W365) and 550 (W550) days of age, and to estimate the heritability of these traits and the breeding values of animals of different breed compositions involving Angus and Zebu breeds in order to evaluate the possible use of these traits as selection criteria in crossbreeding and genetic improvement programs. Records from 5,629 crossbred Angus x Zebu animals born between 1995 and 2004 were used. Univariate and bivariate analyses of the traits were performed using an animal model and Bayesian inference. The effects included in the model were contemporary group, individual heterozygosis, age of animal at recording, and random direct genetic effect of the animal and residual. The size of the chain requested, as well as the burn-in period and thinning interval, was sufficient to obtain convergence of the posterior estimates of the genetic parameters. The heritability estimates obtained in univariate and bivariate analysis were 0.38 and 0.30 for W365 and 0.32 and 0.30 for W550, respectively. The genetic correlation between traits was 0.98. Comparison of the rank of the 10 best sires based on the breeding values for W365 and W550 showed a small difference between the traits studied. The effect of heterozygosity has importance for crossings and for obtaining higher postweaning weights, indicating that the use of animals with maximum individual heterozygosity is advantageous. W365 and W550 were found to be appropriate selection criteria and should be included in breeding programs of crossbred Angus x Zebu cattle.

Accuracies of genomically estimated breeding values from pure-breed and across-breed predictions in Australian beef cattle

BackgroundThe major obstacles for the implementation of genomic selection in Australian beef cattle are the variety of breeds and in general, small numbers of genotyped and phenotyped individuals per breed. The Australian Beef Cooperative Research Center (Beef CRC) investigated these issues by deriving genomic prediction equations (PE) from a training set of animals that covers a range of breeds and crosses including Angus, Murray Grey, Shorthorn, Hereford, Brahman, Belmont Red, Santa Gertrudis and Tropical Composite. This paper presents accuracies of genomically estimated breeding values (GEBV) that were calculated from these PE in the commercial pure-breed beef cattle seed stock sector.MethodsPE derived by the Beef CRC from multi-breed and pure-breed training populations were applied to genotyped Angus, Limousin and Brahman sires and young animals, but with no pure-breed Limousin in the training population. The accuracy of the resulting GEBV was assessed by their genetic correlation to their phenotypic target trait in a bi-variate REML approach that models GEBV as trait observations.ResultsAccuracies of most GEBV for Angus and Brahman were between 0.1 and 0.4, with accuracies for abattoir carcass traits generally greater than for live animal body composition traits and reproduction traits. Estimated accuracies greater than 0.5 were only observed for Brahman abattoir carcass traits and for Angus carcass rib fat. Averaged across traits within breeds, accuracies of GEBV were highest when PE from the pooled across-breed training population were used. However, for the Angus and Brahman breeds the difference in accuracy from using pure-breed PE was small. For the Limousin breed no reasonable results could be achieved for any trait.ConclusionAlthough accuracies were generally low compared to published accuracies estimated within breeds, they are in line with those derived in other multi-breed populations. Thus PE developed by the Beef CRC can contribute to the implementation of genomic selection in Australian beef cattle breeding.

Diverse outcomes of bovine viral diarrhea virus (BVDV) infections in a herd naturally infected during pregnancy

A beef producer purchased pregnant Angus crossbred cows with nursing calves. The purchased cattle, their nursing calves, and subsequent born calves were not initially tested for bovine viral diarrhea virus (BVDV), nor was there a history of vaccination. Bovine viral diarrhea virus subtype 2a was later isolated from an aborted bovine fetus estimated to be 6.5 months gestational age. The fetus had multiple congenital malformations including arthrogryposis, kyphosis, scoliosis, polydactylism, and cardiac overriding aorta. Testing by immunohistochemistry and virus isolation resulted in the detection of potentially persistently infected cattle, including a yearling and a calf born during the same calving season as the aborted fetus. Viruses isolated from the malformed fetus, the yearling, and the calf born during the same calving season were identical. The malformations observed in the aborted fetus were similar to arthrogryposis multiplexa (AM) and contractural arachnodactyly (CA), diseases associated with genetic defects in the Angus breed. The fetus was tested and found negative for the genetic defect linked with AM and CA. This case illustrates that suspect malformations should also be tested for BVDV, and underscores the potential for disease after failed or inadequate biosecurity.

Genetic characterization of a herd of the endangered Danish Jutland cattle

In this paper we present results from a genetic characterization of a herd of the Danish Jutland cattle breed named the Kortegaard herd (n = 135; 57 males and 78 females). The herd is genotyped on the Bovine HD BeadChip microarray with 697,548 evenly spaced SNP across the bovine genome. The aim of the study was to characterize the genetic profile of the Kortegaard herd, which has been closed for several generations, by quantifying the degree of genetic homogeneity within the herd and to compare its genetic profile to that of other cattle breeds. A total of 868 animals from the Angus, Belgian Blue, Charolais, Friesian, Hereford, Holstein, Holstein-Friesian crosses, Limousin, and Simmental breeds was used for genetic profile comparisons. The level of genetic variation within the breeds were quantified by the expected heterozygosity (H(E)), observed heterozygosity (H(O)), average minor allele frequency (MAF), the degree of polymorphism, and runs of homozygosity (ROH), which are contiguous lengths of homozygous genotypes of varying length. Interestingly, the Kortegaard herd had the lowest within-breed genetic variation (lowest H(E), H(O), and MAF), showed moderate levels of short ROH (<5 Mb), and had the highest mean long ROH (>5 Mb) compared to all the other breeds. This is possibly due to recent consanguineous matings, a strong founder effect, and a lack of gene flow from other herds and breeds. We further examined whether the observed genetic patterns in the Kortegaard herd can be used to design breeding strategies for the preservation of the genetic pool by focusing on a subset of SNP outside homozygote regions. By calculating the pairwise identical-by-state between all possible matings, we designed a breeding plan that maximized heterozygosity in the short term. The benefits and limitations of such a breeding strategy are discussed.

A polymorphism in XKR4 is significantly associated with serum prolactin concentrations in beef cows grazing tall fescue

Fescue toxicosis is a common syndrome of poor growth and reproductive performance of beef cattle grazing endophyte-infected tall fescue infected with Lolium arundinaceum Schreb. Together with decreased feed intake, decreased growth rates and tissue necrosis due to vasoconstriction, depressed circulating serum prolactin concentrations are typically observed in cattle afflicted with fescue toxicosis. Polymorphisms within the XK, Kell blood group complex subunit-related family, member 4 (XKR4) gene located on BTA14 have been previously reported to be associated with rump fat thickness, residual feed intake, average daily feed intake and average daily gain in cattle. Associations also have been reported between XKR4 genotype and effectiveness of the dopamine antagonist iloperidone as a treatment of schizophrenia in humans. Domperidone, a related dopamine antagonist, mediates effects of fescue toxicosis on livestock, including restoring depressed concentrations of prolactin. A mixed-breed population of 592 beef cattle grazing endophyte-infected tall fescue was used to examine the association between XKR4 genotype and circulating prolactin concentrations. The SNP rs42646708 was significantly (P = 0.0002) associated with serum prolactin concentrations and explained 2.45% of the phenotypic variation. Effect of genotype at the SNP was tested across five breeds, with significant associations within both Angus (P = 0.0275) and Simmental (P = 0.0224) breeds. These results suggest XKR4 may play a role in mediating the negative effects of fescue toxicosis, and polymorphisms within this gene may be useful markers for selection for genetic resistance to the debilitating effects of endophyte-infected tall fescue.

Quantitative study of Babesia bovis infection in beef cattle from São Paulo state, Brazil

The qPCR technique with SYBR Green was used to estimate the prevalence and level of Babesia bovis infection in beef cattle raised in areas endemic for babesiosis in Brazil, where the animals were continuously exposed to ticks (Rhipicephalus microplus). This is the first report in which qPCR was used to quantify and compare B. bovis DNA in blood of different cattle breeds. Blood samples were collected from 150 animals (75 cows and 75 calves) of the Angus and Nelore breeds and the first generation of an Angus and Nelore cross (AxN). Blood samples from the jugular vein were used for DNA extraction and determination of packed cell volume (PCV), while samples from peripheral veins were used for microscopic parasite detection. Although no piroplasms of B. bovis were found in blood smears, DNA amplification using qPCR revealed that all of the 150 animals, except two calves and one cow, were positive. The number of copies of B. bovis DNA was higher (p<0.05) in the Angus than in the Nelore and AxN animals, for both calves and cows, but no significant difference was found between the Nelore and AxN groups. These results suggest that a heterotic effect was present, since the results from the crossbred animals significantly deviated from the mean of the two parental groups, while closely approaching that of the Nelore group. In the Nelore and AxN groups, calves showed higher infection levels than cows (p<0.05), while for the Angus group the difference was found to be non-significant. Within each animal age group, the breed groups with higher infection levels were those with lower PCV values. However, within each breed group, no significant correlations were found between the number of DNA copies and PCV according to animal age.The qPCR method applied here allowed the observation that although there are no differences in the prevalence of infection among breed groups, Nelore and AxN cattle are able to maintain infection by B. bovis at lower levels than the Angus cattle.

Amounts of essential and non-essential amino acids and the ratio in Lithuania bred cattle meat

The aim of the research was to determine the amounts of essential and non-essential amino acids and the ratio in various breed cattle meat. The content of amino acids and the ratio at the longest dorsal muscle (musculus longissimus dorsi) was determined analyzing Angus, Hereford, Charolais, Limousine purebreds, Lithuanian Black and White x Charolais (LTBWxCHA) crossbreed, Lithuanian Black and White x Limousine (LTBWxLI) crossbreed, Lithuanian Black and White x Simmental (LTBWxSI) crossbreed and Lithuanian Red x Limousine (LTRxLI) crossbreed. Analyzing the research results it was noticed that Lithuanian Black and White cattle breed meat contained the highest total amount of amino acids and Angus breed cattle meat contained the smallest amounts. The difference amounted to 33.87 g/kg or 4.1 percent (p&lt;0.01). While comparing total amounts of amino acids at the purebred cattle breeds and the crossbreeds, it was noticed that the meat of purebred cattle contained higher amounts of amino acids, the difference ranging between 18.54 and 19.00 g/kg or 2.23-2.28 percent (p&lt;0.01). Purebred cattle meat contains higher amounts of essential amino acids compared to crossbreed cattle meat. The meat of Aubrac and Angus breeds was determined to have the highest meat protein sufficiency rate. The lowest biological values were determined at Lithuanian Black and White x Charolais crossbreed meat. The highest amount of the amino acid leucine was observed in Aubrac breed cattle meat (p&lt;0.05). The difference of the leucine amounts reached up to 0.45 g/kg (p&lt;0.01) comparing to various crossbreed cattle meat.

Does Rhipicephalus microplus tick infestation increase the risk for myiasis caused by Cochliomyia hominivorax in cattle?

The larval phase of Cochliomyia hominivorax (screwworm) is an obligate parasite of vertebrate animals, particularly mammals, and widespread in South America, where it remains one of the most important parasitic diseases of domestic animals. The skin of cattle highly infested by ticks, with cutaneous lesions, exudation of tissue fluid and blood scent seems to produce the ideal environment for fly attraction. However, an association between these parasites was never investigated. The aim of this work was to verify if there is an association between Rhipicephalus microplus tick load and the occurrence of C. hominivorax myiasis in cattle, and to quantify the risk. Sixty bovine (Bos taurus taurus, Angus breed) under field conditions were observed for 24 weeks, during which weekly tick counts and examination for the presence of myiasis were performed. There was a significant association between a high tick burden (24-week mean above 50 ticks per animal) and myiasis occurrence (P=0.0102). The calculated relative risk (RR) for C. hominivorax myiasis occurrence in cattle with high tick burden was 3.85 (CI95%=1.23–12.13); indicating that cattle highly parasitized by R. microplus have about four times more risk of myiasis than those with a low parasite load. As far as we aware, this is the first statistically based evidence of the relationship between R. microplus parasitic load and occurrence of myiasis by C. hominivorax. This result could be useful for the design of integrated control strategies for these parasites and to provide more information for the understanding of cattle tick parasitism in cattle production.

Production and carcass traits of purebred Nordic Red and Nordic Red×beef breed crossbred bulls

SUMMARYThe objective of the current study is to determine the beef production traits of purebred Nordic Red (NR) and NR×beef breed crossbred bulls. The data collected from slaughterhouses included observations of 164 812 purebred NR, 2329 NR×Aberdeen Angus, 1466 NR×Blonde d'Aquitaine, 1044 NR×Charolais, 782 NR×Hereford, 5293 NR×Limousin and 1270 NR×Simmental bulls. For estimating valuable cuttings, a separate dataset including a total of 16 827 observations was collected. Crossbreeding NR cows with late-maturing breeds (Blonde d'Aquitaine, Charolais, Limousin or Simmental) had favourable effects on carcass gain, conformation and proportion of high-value joints of the progeny when compared with purebred NR bulls. No advantages in proportion of valuable cuttings seemed to be obtained by crossbreeding with Aberdeen Angus or Hereford breeds, while the improvements in gain and conformation were intermediate compared with the late-maturing crossbreds. A feeding experiment comprised 36 bulls: nine purebred NR, nine NR×Aberdeen Angus (NR×Ab), nine NR×Limousin (NR×Li) and nine NR×Blonde d'Aquitaine (NR×Ba). The animals were offered total mixed ration (TMR) ad libitum. The dry matter (DM) of the TMR consisted of grass silage (500 g/kg DM), rolled barley (425 g/kg DM) and rapeseed meal (75 g/kg DM). There were no differences in DM, energy or nutrient intakes between NR and crossbred bulls during the feeding experiment. Instead, the carcass gain of the NR×Ba bulls was 13% higher than that of the pure NR bulls. In addition, the carcass gain of the NR×Li bulls tended to be 8% higher than that of the NR bulls. The feed (kg DM/kg carcass gain) and energy (MJ/kg carcass gain) conversion rates of the NR×Ba bulls tended to be better compared with purebred NR bulls. There were no differences in feed or energy conversion between NR, NR×Ab and NR×Li bulls. In conclusion, crossbreeding, especially with late-maturing bulls, largely improved carcass production compared with purebred NR bulls. The feeding experiment indicates that there is no difference in DM intake between pure NR and crossbred bulls when animals are fed with high-energy rations. Therefore, differences in growth and carcass traits describe well the economic superiority of crossbreds compared with pure dairy bulls from beef producers’ point of view.

Genotype×production environment interaction for weaning weight in Angus populations of Brazil and Uruguay

The objective of this study was to define production environments by grouping different environmental factors and, consequently, to assess genotype by production environment interactions on weaning weight (WW) in the Angus populations of Brazil and Uruguay. Climatic conditions were represented by monthly temperature means (°C), minimum and maximum temperatures in winter and summer respectively and accumulated rainfall (mm/year). Mode in month of birth and weaning, and calf weight (kg) and age (days) at weaning were used as indicators of management conditions of 33 and 161 herds in 13 and 34 regions in Uruguay and Brazil, respectively. Two approaches were developed: (a) a bi-character analysis of extreme sub-datasets within each environmental factor (bottom and top 33% of regions), (b) three different production environments (including farms from both countries) were defined in a cluster analysis using standardized environmental factors. To identify the variables that influenced the cluster formation, a discriminant analysis was previously carried out. Management (month, age and weight at weaning) and climatic factors (accumulated rainfalls and winter and summer temperatures) were the most important factors in the clustering of farms. Bi or trivariate analyses were performed to estimate heritability and genetic correlations for WW in extreme sub-datasets within environmental factor or between clusters, using MTDFREML software. Heritability estimates of WW in the first approach ranged from 0.27 to 0.54, and genetic correlations between top and bottom sub-datasets within environmental factors, from −0.29 to 0.70. In the cluster approach, heritabilities were 0.58±0.04 for cluster 1, 0.31±0.01 for Cluster 2 and 0.40±0.02 for Cluster 3. Genetic correlations were 0.27±0.08, 0.32±0.09 and 0.33±0.09, between clusters 1 and 2, 1 and 3, and 2 and 3, respectively. Both approaches suggest the existence of genotype x environment interaction for weaning weight in Angus breed of Brazil and Uruguay.