Zebu Breeds Research Articles

<p><strong>Sensitivity of Senepol and Caracu breeds to parasitism by <em>Rhipicephalus microplus</em></strong></p>

Taurine breeds and animals crossbred for genetic resistance to Rhipicephalus microplus have been the focus of several studies aimed at producing better responses of cattle to tick infestations and seeking to reduce treatment costs and improve the quality of bovine byproducts. Another way to increase gains is the introduction of taurine breeds with the goal of obtaining morphological and physiological characteristics more adapted to production. Although several studies have compared taurine and zebu breeds, little is known about the differences found within the taurine group. Therefore, the present study aimed to evaluate the sensitivity of the Senepol and Caracu breeds to artificial R. microplus infestations. For this purpose, a stall test was conducted on 16 Caracu and 14 Senepol bulls. The animals were subjected to artificial infestation with a total of 15,000 R. microplus larvae per animal. The Senepol group accounted for 71.7% of the retrieved engorged female ticks. The biological parameters analyzed that showed a significant difference included the mean number of engorged female ticks retrieved (p = 0.000), weight of engorged female ticks (p = 0.000), rate of engorged female ticks retrieved (p = 0.03) and egg mass weight (p = 0.032). Thus, the present study demonst rated a higher susceptib ility of the Senepol breed to parasitism by the Asian blue tick than the Caracu breed, providing support for new studies on the subjects of genetic resistance, animal breeding and cattle production.

Heterozygous Single-Nucleotide Polymorphism Genotypes at Heat Shock Protein 70 Gene Potentially Influence Thermo-Tolerance Among Four Zebu Breeds of Nigeria.

Genetic variants at heat shock protein 70 gene and their influence on heat stress (HS) tolerance were studied among selected Nigeria zebu, namely, 25 White Fulani (WF), 21 Sokoto Gudali (SG), 21 Red Bororo (RB), and 23 Ambala (AM). Detection of single nucleotide polymorphism (SNP) followed by determination of genotype and genotypic frequency was made among the selected breeds. The heat tolerance coefficient (HTC) was determined from thermo-related parameters including body temperature, rectal temperature, and respiratory rate. Thermo-Tolerance was evaluated through the SNP–thermo-parameter relationship. Statistical analyses were done using the GLM procedure in SAS. A quantitative real-time/high-resolution melting-based assay detected twelve genetic variants. Five of these were common and shared across all breeds of cattle. Of the remaining seven variants, three were specifically identified in AM, two in SG, and two in RB. Also, SNPs were evaluated and four unique SNPs (C151T, C146T, G90A, and C219A) were identified. Heterozygous animals had lower HTC suggesting their potential to withstand HS than homozygous counterparts. The WF and RB animals had significantly lower values for all parameters (BT, RT, RR, and HTC) compared to AM and SG breeds. Thermo-related parameters were significantly different (P < 0.001), and it is recommended that screening of SNPs in zebu is needed to enable selection for improved thermo-tolerance.

Using Bioelements Isotope Ratios and Fatty Acid Composition to Deduce Beef Origin and Zebu Feeding Regime in Cameroon.

The purpose of this study was to address the lack of knowledge regarding the stable isotopic composition of beef from zebu cattle reared in tropical Africa. Sixty beef carcasses belonging to the most common zebu breeds (Goudali, white Fulani, and red Mbororo) were selected and classified according to their subcutaneous fat color (white, cream or yellow). The stable isotope ratios of five bioelements—H, O, C, N, and S—in muscle fractions and the fatty acids composition were analyzed. Zebu meat from Cameroon shows peculiar δ13C values, related to the almost exclusive intake of grazed tropical grasses with photosynthetic cycle C4. It also shows δ2H and δ18O values higher than those reported in other areas of the world and correlated with the isotopic composition of animal drinking water. The white subcutaneous fat (“white type”) zebu showed higher δ2H and lower δ13C than the “yellow type”, that is correlated with a higher content of polyunsaturated fatty acid (PUFA) and a lower amount of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA). Multielement analysis seems to provide promising results for tracing the regional origin of Cameroon beef and some aspects of the livestock system, such as the nutritional status of the animals.

Genetic assessment of BoLA-DRB3 polymorphisms by comparing Bangladesh, Ethiopian, and Korean cattle.

Attributable to their major function in pathogen recognition, the use of bovine leukocyte antigens (BoLA) as disease markers in immunological traits in cattle is well established. However, limited report exists on polymorphism of the BoLA gene in zebu cattle breeds by high resolution typing methods. Thus, we used a polymerase chain reaction sequence-based typing (PCR-SBT) method to sequence exon 2 of the BoLA class II DRB3 gene from 100 animals (Boran, n = 13; Sheko, n = 20; Fogera, n = 16; Horro, n = 19), Hanwoo cattle (n = 18) and Bangladesh Red Chittagong zebu (n = 14). Out of the 59 detected alleles, 43 were already deposited under the Immuno Polymorphism Database for major histocompatibility complex (IPD-MHC) while 16 were unique to this study. Assessment of the level of genetic variability at the population and sequence levels with genetic distance in the breeds considered in this study showed that Zebu breeds had a gene diversity score greater than 0.752, nucleotide diversity score greater than 0.152, and mean number of pairwise differences higher than 14, being very comparable to those investigated for other cattle breeds. Regarding neutrality tests analyzed, we investigated that all the breeds except Hanwoo had an excess number of alleles and could be expected from a recent population expansion or genetic hitchhiking. Howbeit, the observed heterozygosity was not significantly (p < 0.05) higher than the expected heterozygosity. The Hardy Weinberg equilibrium (HWE) analysis revealed non-significant excess of heterozygote animals, indicative of plausible over-dominant selection. The pairwise FST values suggested a low genetic variation among all the breeds (FST = 0.056; p < 0.05), besides the rooting from the evolutionary or domestication history of the cattle. No detached clade was observed in the evolutionary divergence study of the BoLA-DRB3 gene, inferred from the phylogenetic tree based on the maximum likelihood model. The investigation herein indicated the clear differences in BoLA-DRB3 gene variability between African and Asian cattle breeds.

Concurrent Infection of Fascioliasis andTrypanosomosis and Associated Risk Factors in Local Zebu Breed Cattle of Western Ethiopia.

BackgroundA cross-sectional study was conducted from late October 2016 to June 2017, with the primary objective of estimating and analyzing the concurrent occurrence of both fascioliasis and trypanosomosis infections and associated risk factors along the tsetse-infested Didessa river basin.MethodsThe methodology applied was based on stratified sampling for the parasitological study, with entomological and malacological surveys, including fly dissection.ResultsThe result of variance-ratio testing between trypanosomosis and fascioliasis infections (mean prevalence 0.117±0.322 and 0.283±0.451, respectively), was statistically significant (P[F>f]=0), with higher observed fascioliasis infection (n=147, 28.27%). Severe anemia was observed in trypanosomosis infection, with mean packed cell volume of 19.57 (OR=0.71, P>|z|=0.000), and vast fascioliasis infections identified among cattle with medium and poor body condition in terms of weight (n=91 [32.73%] and n=38 [21.47%]). On entomological study, 578 (62.62%) and 345 (37.38%) female and male Glossina tachinoides fly species were cached, respectively, with overall mean flies/trap/day of 5.19 (n=923). Despite the prevalence of trypanosomosis in infected cattle, of 130 G. tachinoides flies dissected, only three were found to be positive for an infection rate of 2.31%. Malacological study identified three snail species known to maintain fascioliasis: Lymnea truncatula (n=28, 45.16%), Lymnea natalensis (n=23, 37.10%), and Biomphalaria (n=11, 17.74%). Concurrent infection with fascioliasis and trypanosomosis was mainly associated with the co-occurrence of their intermediate host snails and Glossina flies, respectively, with 4.42% (n=23) prevalence.ConclusionThis study clearly demonstrated that the former parasite was highly associated with emaciation, whereas the second was responsible for anemia. In future,researchers should focus solely on estimating meat and milk production of local cattle to assess the economic impact of the study parasites.

FEEDLOT PERFORMANCE AND CARCASS CHARACTERISTICS OF ZEBU CATTLE IN THE MALI SAHEL ZONE I. SUPPLEMENTARY FEEDING IN ADDITION TO NATURAL PASTURE

Investigations into the performance of Peulh and Maure Zebu breeds of cattle to supplementary feeding of cotton seed and rice bran in addition to grazing natural pasture during the rainy and dry seasons were conducted in the Sahe one of Mali Republic. 96 steers made up of Peulh and Maure Zebu breed with age ranging between 30 and 55 months were grouped into five ._-­the control group grazed on natural pasture alone while four test groups were fed supple­mentary diets in addition to free grazing. Parameters based mainly on feed intake, rate of gain, feed conversion and carcass characteristics showed Maure gained weight significantly (P &lt; - 0.05) faster (318.5g/d) than Peulh (2920) when a feeding trial which lasted 56 weeks was conducted. All steers on test diets performed better than the control except during the second rainy season when a 'compensatory growth' was recorded for the steers under the control. treatment. Younger animals (30 months old) gained weight (337.1g/d) significantly faster (P&lt; 0.05) than the older (55 month-old) ones (273.40). While dressing percentage ranged between 48 and 56, test animals had significantly better dressing percentage of 55.4% (P &lt; 0.05) than the control (48.2%). No diffe­rence was-recorded between the breed or age groups. Animals fed on pasture alone had 10.7% capacity of rumen content as perc­centag€ of carcass weight compared with 7.5% fir test diets.

Prevalence of bovine mastitis in smallholder lactating dairy farms in Hawassa, SNNPR, Ethiopia

A cross sectional study was conducted between November 2015 and February 2016 in Hawassa town, SNNPR, Ethiopia to determine the overall mastitis prevalence and identify the role of some selected risk factors in 183 randomly selected small holder lactating dairy cows of 53 high grade Holstein Friesian, 113 Holstein indigenous zebu cross and 17 indigenous zebu breeds. The prevalence of clinical mastitis was determined through examination of abnormalities of milk, udder or cow. The prevalence of subclinical mastitis determined by using indicator paper test. From total 183 lactating dairy cows examined for bovine mastitis 9(4.9%) had clinical mastitis, while 56(30.6%) subclinical mastitis. Out of 9(4.9%) clinical mastitis, 9.43 and 3.53% occurred in high grade Holstein and Holstein indigenous zebu, respectively, but indigenous zebu breed was found not affected. Subclinical mastitis at cow level based on indicator paper test was significantly high (32.07%) in Holstein, (30.9%) in cross breed and (23.5%) in indigenous zebu (p&lt;0.05). Quarter level subclinical mastitis prevalence based on indicator paper test was 32.07, 30.2% and 23.5% in Holstein, cross breed and indigenous zebu, respectively. From the potential risk factors considered, breed (X2=17.3, p&lt;0.05), presence of teat lesion and tick infestation (X2=7.73, p&lt;0.05), stage of lactation (X2=13.8, p&lt;0.05), and parity number (X2=19.4, p&lt;0.05) had significant effect on the prevalence of subclinical mastitis. Considering the possible significant economic losses that could be incurred by both clinical and subclinical mastitis, attention should be paid for further detailed investigation and control measures.

Effect of cold drinking water on performance, rectal temperature, respiratory rate of Zebu and Jersey cattle in Ibadan, Nigeria

High ambient temperature and relative humidity exert a negative effect on the performance of both Bostaurus and Bosindicus cattle in Nigeria. The use of water sprinklers to shower cattle may have the ability to mitigate the effect of heat stress. In this study, cold drinking water (10 C 15 C) and ordinary drinking water (20 C -25 C) were offered to six Jersey and six Sokoto Gudali heifers to compare the effect on heat stress. They were divided into two treatments each. Each treatment had three replicates and cattle were assigned in a completely randomised design to the treatment. Rectal temperature, respiratory rate, dry matter intake, daily weight gain and percentage body weight were measured. At three months of administration of treatment, mean morning and afternoon RT varied from 37.94C to39.17 C for Sokoto Gudali and 37.97 C to 39.21 C for Jersey heifers, RR varied from 20.54 bpm to 30.73 bpm for Gudali and 32.17 bpm to 42.63 bpm for Jersey heifers. There were significant (P&lt;0.05) differences in respiratory rate, rectal temperature and dry matter intake between both the zebu and exotic heifers given ordinary water and those given cold water when treatments were administered. Mean RT was 38.99 C and 38.14 C for Gudali and 38.98 C and 38.34 C for Jersey heifers while mean RR was 28.12 bpm and 23.11 bpm for Gudali and 39.89 and 33.78 bpm for Jersey heifers. DMI were 4.14 kg/d and 6.01 kg/d, daily weight gain were 0.27 kg/d and 0.50 kg/d and FCR were 15.33 and 12.02. Cold drinking water is an effective method of ameliorating heat stress in zebu and Jersey breeds of cattle.

Breed direct, maternal and heteros is effects due to Angus, Caracu, Hereford and Nelore on carcass and meat quality traits of cull cows

• The Caracu breed can be used in crossbreeding with Angus to take heterosis and also to improve meat tenderness. • The carcass weight and meat tenderness can be obtained by crossing taurine breeds. • The cross between taurine and Zebu breeds leads to higher carcass yield and ribeye area. Meat is an end-of-life by-product from cows that fail to reproduce. Thus, the objective of this study was to determine breed additive and heterosis effects on carcass traits and characteristics of the meat from beef cows raised in southern Brazil. Angus (A), Hereford (H), Nelore (N), A × H (AH), H × A (HA), A × N (AN), N × A (NA) and Caracu (C) × A (CA) cows were slaughtered when they did not become pregnant for a second season. Slaughter weight (SW), hot carcass weight (CW), carcass yield (CY), ribeye area (REA), pH value, water holding capacity (WHC), tenderness (MT), moisture (MM), ether extract (EE), carcass fat score (CFS), marbling score (MS), subcutaneous fat thickness (SFT) and L*, a* and b* measures of color of the fat and meat color were evaluated. Taurine x taurine heterosis effects increased SW and to a lesser degree CW, and improved MT. Taurine x indicine heterosis increased REA, a* and b*, and decreased L* and EE. Direct breed additive effects attributable to A increased SW but decreased CY and thus had no detectable effect on CW. Direct breed additive effects of C decreased CFS, SFT, CY and MM. Finally, direct breed additive effects of H and C similarly decreased CFS and SFT. Maternal breed additive effects were generally unremarkable except for slight effects of H reducing a* and b*. Thus, SW and MT may be increased by crossbreeding with taurine breeds, while CY and REA can be increased by using zebu-influenced cattle. The desirable carcass composition of CA cows and their MT and color comparable to taurine crossbred cows make this crossbred cow a viable alternative for producers in southern Brazil.

Applying the Metafounders Approach for Genomic Evaluation in a Multibreed Beef Cattle Population.

Pedigree information is incomplete by nature and commonly not well-established because many of the genetic ties are not known a priori or can be wrong. The genomic era brought new opportunities to assess relationships between individuals. However, when pedigree and genomic information are used simultaneously, which is the case of single-step genomic BLUP (ssGBLUP), defining the genetic base is still a challenge. One alternative to overcome this challenge is to use metafounders, which are pseudo-individuals that describe the genetic relationship between the base population individuals. The purpose of this study was to evaluate the impact of metafounders on the estimation of breeding values for tick resistance under ssGBLUP for a multibreed population composed by Hereford, Braford, and Zebu animals. Three different scenarios were studied: pedigree-based model (BLUP), ssGBLUP, and ssGBLUP with metafounders (ssGBLUPm). In ssGBLUPm, a total of four different metafounders based on breed of origin (i.e., Hereford, Braford, Zebu, and unknown) were included for the animals with missing parents. The relationship coefficient between metafounders was in average 0.54 (ranging from 0.34 to 0.96) suggesting an overlap between ancestor populations. The estimates of metafounder relationships indicate that Hereford and Zebu breeds have a possible common ancestral relationship. Inbreeding coefficients calculated following the metafounder approach had less negative values, suggesting that ancestral populations were large enough and that gametes inherited from the historical population were not identical. Variance components were estimated based on ssGBLUPm, ssGBLUP, and BLUP, but the values from ssGBLUPm were scaled to provide a fair comparison with estimates from the other two models. In general, additive, residual, and phenotypic variance components in the Hereford population were smaller than in Braford across different models. The addition of genomic information increased heritability for Hereford, possibly because of improved genetic relationships. As expected, genomic models had greater predictive ability, with an additional gain for ssGBLUPm over ssGBLUP. The increase in predictive ability was greater for Herefords. Our results show the potential of using metafounders to increase accuracy of GEBV, and therefore, the rate of genetic gain in beef cattle populations with partial levels of missing pedigree information.

The patterns of admixture, divergence, and ancestry of African cattle populations determined from genome-wide SNP data

BackgroundHumpless Bos taurus cattle are one of the earliest domestic cattle in Africa, followed by the arrival of humped Bos indicus cattle. The diverse indigenous cattle breeds of Africa are derived from these migrations, with most appearing to be hybrids between Bos taurus and Bos indicus. The present study examines the patterns of admixture, diversity, and relationships among African cattle breeds.MethodsData for ~ 40 k SNPs was obtained from previous projects for 4089 animals representing 35 African indigenous, 6 European Bos taurus, 4 Bos indicus, and 5 African crossbred cattle populations. Genetic diversity and population structure were assessed using principal component analyses (PCA), admixture analyses, and Wright’s F statistic. The linkage disequilibrium and effective population size (Ne) were estimated for the pure cattle populations.ResultsThe first two principal components differentiated Bos indicus from European Bos taurus, and African Bos taurus from other breeds. PCA and admixture analyses showed that, except for recently admixed cattle, all indigenous breeds are either pure African Bos taurus or admixtures of African Bos taurus and Bos indicus. The African zebu breeds had highest proportions of Bos indicus ancestry ranging from 70 to 90% or 60 to 75%, depending on the admixture model. Other indigenous breeds that were not 100% African Bos taurus, ranged from 42 to 70% or 23 to 61% Bos indicus ancestry. The African Bos taurus populations showed substantial genetic diversity, and other indigenous breeds show evidence of having more than one African taurine ancestor. Ne estimates based on r2 and r2adj showed a decline in Ne from a large population at 2000 generations ago, which is surprising for the indigenous breeds given the expected increase in cattle populations over that period and the lack of structured breeding programs.ConclusionAfrican indigenous cattle breeds have a large genetic diversity and are either pure African Bos taurus or admixtures of African Bos taurus and Bos indicus. This provides a rich resource of potentially valuable genetic variation, particularly for adaptation traits, and to support conservation programs. It also provides challenges for the development of genomic assays and tools for use in African populations.

Fitting of non-linear models to characterize the growth of five zebu cattle breeds

The analyzed database contained growth information of five zebu breeds with live weight (LW) measurements in the range from birth to 1095 days of age. The objectives of this study were to identify the non-linear model (NLM) with the best fit to describe the growth curve. The number of LWs analyzed, per breed and sex (males and females), were: 21152 and 8269 in Indubrasil (IND), 40071 and 20968 in Nelore (NEL), 20143 and 12294 in Gyr (GYR), 5585 and 4727 in Guzerat (GUZ), 29310 and 9347 in Sardo Negro (SAN). The evaluated NLMs were Brody (BRO), Bertalanffy, Gompertz, Mitscherlich (MIT), Meloun III (ME3), and Logistic. The models fitness was compared using the: Akaike and Bayesian information criteria, coefficient of determination, Durbin-Watson statistic, mean prediction error, prediction error variance, standard error of the model. The linear relationship between the LW and the predicted data (PRE) was analyzed. All the NLMs showed a goodness of fit of 94 % or higher and tend to underestimate the predictions. A positive autocorrelation in the residuals was observed in IND and GUZ females, and in GUZ males. For both sexes, in IND and GUZ the selected model was BRO, for GYR and SAN was MIT. In NEL, MIT was selected for males and ME3 for females. For the estimated adult weight, the mean values (males and females) were: 744.9 and 506.4 kg in IND, 804.5 and 393.5 kg in NEL, 695.4 and 527.3 kg in GYR, 855.0 and 754.5 kg in GUZ, 871.6 and 615.8 kg in SAN. With the selected models, the populations show a growth curve without an inflection point, and a constant growth rate. The correlation between growth rate and adult weight was negative in all the analyses. The average correlation between LW and PRE was 0.87. The PRE explained, on average, 76 % of the LW variability. In the analysis of predictive capacity, the LW change rate per change unit in the PRE showed a one-to-one relationship in almost every analysis, for GUZ, SAN, and GYR males, the LW change was 1.09, 1.03, and 1.01, respectively.

Understanding functional implication of β-casein gene variants in four cattle breeds characterized using AmpliSeq approach.

Here, we designed a custom panel targeting whole β-casein gene SNPs of zebu and taurine cattle breeds to identify variants and applicability in dairy cattle genotyping. We sequenced two libraries consisting of different pools of primer sets from 95 individuals on the Illumina MiSeq. Consequently, over 92% target regions were amplified and 71 SNPs were available after quality filtering. Only three intronic variants were novel while majority of the identified variants were catalogued in dbSNP as known variants. Identified missense SNPs lead to variant A1/A2, B, F and A3, located in exon 7 only. For confirmation, A1/A2 locus was genotyped using PCR-RFLP. Variant B was observed in all animals, either in homozygous or in heterozygous form. Variants A1, F and A3 predicted to have a deleterious effect on protein function by decreasing the structural stability. Additionally, SIFT score revealed that the A1 variant might affect the protein function.

Characterization of bovine MHC DRB3 diversity in global cattle breeds, with a focus on cattle in Myanmar

BackgroundMyanmar cattle populations predominantly consist of native cattle breeds (Pyer Sein and Shwe), characterized by their geographical location and coat color, and the Holstein-Friesian crossbreed, which is highly adapted to the harsh tropical climates of this region. Here, we analyzed the diversity and genetic structure of the BoLA-DRB3 gene, a genetic locus that has been linked to the immune response, in Myanmar cattle populations.MethodsBlood samples (n = 294) were taken from two native breeds (Pyer Sein, n = 163 and Shwe Ni, n = 69) and a cattle crossbreed (Holstein-Friesian, n = 62) distributed across six regions of Myanmar (Bago, n = 38; Sagaing, n = 77; Mandalay, n = 46; Magway, n = 46; Kayin, n = 43; Yangon, n = 44). In addition, a database that included 2428 BoLA-DRB3 genotypes from European (Angus, Hereford, Holstein, Shorthorn, Overo Negro, Overo Colorado, and Jersey), Zebuine (Nellore, Brahman and Gir), Asian Native from Japan and Philippine and Latin-American Creole breeds was also included. Furthermore, the information from the IPD–MHC database was also used in the present analysis. DNA was genotyped using the sequence-based typing method. DNA electropherograms were analyzed using the Assign 400ATF software.ResultsWe detected 71 distinct alleles, including three new variants for the BoLA-DRB3 gene. Venn analysis showed that 11 of these alleles were only detected in Myanmar native breeds and 26 were only shared with Asian native and/or Zebu groups. The number of alleles ranged from 33 in Holstein-Friesians to 58 in Pyer Seins, and the observed versus unbiased expected heterozygosity were higher than 0.84 in all the three the populations analyzed. The FST analysis showed a low level of genetic differentiation between the two Myanmar native breeds (FST = 0.003), and between these native breeds and the Holstein-Friesians (FST < 0.021). The average FST value for all the Myanmar Holstein-Friesian crossbred and Myanmar native populations was 0.0136 and 0.0121, respectively. Principal component analysis (PCA) and tree analysis showed that Myanmar native populations grouped in a narrow cluster that diverged clearly from the Holstein-Friesian populations. Furthermore, the BoLA-DRB3 allele frequencies suggested that while some Myanmar native populations from Bago, Mandalay and Yangon regions were more closely related to Zebu breeds (Gir and Brahman), populations from Kayin, Magway and Sagaing regions were more related to the Philippines native breeds. On the contrary, PCA showed that the Holstein-Friesian populations demonstrated a high degree of dispersion, which is likely the result of the different degrees of native admixture in these populations.ConclusionThis study is the first to report the genetic diversity of the BoLA-DRB3 gene in two native breeds and one exotic cattle crossbreed from Myanmar. The results obtained contribute to our understanding of the genetic diversity and distribution of BoLA-DRB3 gene alleles in Myanmar, and increases our knowledge of the worldwide variability of cattle BoLA-DRB3 genes, an important locus for immune response and protection against pathogens.

Whole genome characterization of autochthonous Bos taurus brachyceros and introduced Bos indicus indicus cattle breeds in Cameroon regarding their adaptive phenotypic traits and pathogen resistance

Background African indigenous taurine cattle display unique adaptive traits shaped by husbandry management, regional climate and exposure to endemic pathogens. They are less productive with respect to milk and meat production which has been associated with amongst others, small size, traditional beliefs, husbandry practices, limited feed resources, disease burden and lack of sustained breeding for trait improvement. This resulted in the severe dwindling of their population size rendering them vulnerable to extinction.The Namchi taurine cattle breed is referred to as [Namchi (Doayo)] and shows resistance traits against trypanosome infection and exposure to tick infestation. Nonetheless, the historically later introduced Zebu cattle are the main cattle breeds in Africa today, even though they suffer more from locally prevailing pathogens.By using a whole genome sequencing approach, we sequenced with high depth for the first time the genomes of five cattle breeds from Cameroon in order to provide a valuable genetic resource for future African cattle breeding: the Namchi, an endangered trypano-tolerant taurine breed, the Kapsiki, an indigenous trypano-susceptible taurine breed, and three Zebu (Bos indicus indicus) breeds: Ngaoundere Gudali, White Fulani and Red Fulani.ResultsApproximately 167 Gigabases of raw sequencing data were generated for each breed and mapped to the cattle reference genomes ARS-UCD1.2 and UMD3.1.The coverage was 103 to 140-fold when aligning the reads to ARS-UCD1.2 with an average mapping rate of ~ 99%, and 22 to 30-fold when aligning the reads to UMD3.1 with an average mapping rate of ~ 64%. The single nucleotide polymorphisms (SNPs) obtained from analysis using the genome ARS-UCD1.2 were compared with reference genomes of European Bos taurus Holstein, the Asian Bos indicus Brahman, and the African trypanotolerant N’Dama breeds.A total of ~ 100 million (M) SNPs were identified and 7.7 M of those were breed-specific. An approximately 11.1 M constituted of small insertions and deletions. By using only breed-specific non-synonymous variants we identified genes as genetic signatures and associated Gene Ontology (GO) terms that could explain certain cattle-breed specific phenotypes such as increased tolerance against trypanosome parasites in the Namchi breed and heat tolerance in the Kapsiki breed. Phylogenetic analysis grouped, except for Namchi, the Bos taurus breeds Kapsiki, N’Dama and Holstein together while the B. indicus breeds White and Red Fulani, Gudali and Brahman clustered separately. The deviating result for Namchi indicates a hybrid status of the selected animal with a recent introgression of Zebu genes into its genome.ConclusionsThe findings provide the first comprehensive set of genome-wide variant data of the most important Cameroonian cattle breeds. The genomic data shall constitute a foundation for breed amelioration whilst exploiting the heritable traits and support conservation efforts for the endangered local cattle breeds.

Genetic Improvement Strategy of Indigenous Cattle Breeds: Effect of Cattle Crossbreeding Program in Production Performances

The aim of the review is to summarize the fragmented production performance information on the effects of cattle crossbreeding in different parts of the globe. Most studies indicated that cattle crossbreeding practices conducted under extensive management system for small scale dairy farms is attractive because the optimum requirement (50-62.5%) of exotic cattle blood level inheritance was maintained. However, most developing countries do not use systematic crossbreeding programme. For example, dairy cattle crossbreeding programme in Ethiopia lacks clear breeding policy regarding the breed type to be used and the level of exotic blood inheritance across different agro-ecology and production system. Heterosis is an essential advantage of crossbreeding and maximum heterosis is realized in the first cross (F1) of distinctly different breeds. The purpose of crossbreeding in beef cattle is partly to combine breed differences and partly to make use of heterosis to improve production. Heterosis is highest in F1 generation compared to F2, F3 and F4 crossbred generations. Therefore, terminal crossbreeding is very important in livestock production particularly in beef production. Holstein Friesian dairy cattle produce 40-60% lowered milk yield under tropical and subtropical conditions compared to temperate conditions, and this is due to the exposure of the animals to the different stress factors in the tropical and subtropical conditions. The review also revealed that crossbreeding programme has significant effect in birth weight because all F1 crossbred calves have highest birth weight compared to the purebred calves of Zebu, Sanga and Zenga breeds. Heterosis in a sound crossbreeding program could increase productivity in the beef cow herd by as much as 26% over a comparable straight breeding program. In general, crossbreeding in tropical countries is undertaken to combine superior hardiness, heat tolerance, disease tolerance and/or resistance and environmental adaptability of indigenous cattle with superior milk yield and faster growth rates of exotic temperate breeds. Crossbreeding is one tool to minimize the negative impacts of inbreeding depression in livestock sector. Through crossbreeding there is a chance to have highly productive and adapted breeds. Crossbreeding also affects milk fat and protein compositions of purebred cattle. However, if crossbreeding is indiscriminate and uncontrolled, it may result in poor production performance. Furthermore, a number of studies indicated that indiscriminate and uncontrolled crossbreeding is a major threat to sustainable conservation and utilization of indigenous cattle breeds. Therefore, crossbreeding must be introduced in controlled farms.

Genetic Architecture of Carcass and Meat Quality Traits in Montana Tropical® Composite Beef Cattle.

The Montana Tropical® Composite is a recently developed beef cattle population that is rapidly expanding in Brazil and other tropical countries. This is mainly due to its improved meat quality and adaptation to tropical climate conditions compared to Zebu and Taurine cattle breeds, respectively. This study aimed to investigate the genetic architecture of ultrasound-based carcass and meat quality traits in Montana Tropical® Composite beef cattle. Therefore, we estimated variance components and genetic parameters and performed genome-wide association studies using the weighted single-step Genomic Best Linear Unbiased Prediction (GBLUP) approach. A pedigree dataset containing 28,480 animals was used, in which 1,436 were genotyped using a moderate-density Single Nucleotide Polymorphism panel (30K; 30,105 SNPs). A total of 9,358, 5,768, 7,996, and 1,972 phenotypic records for the traits Longissimus muscle area (LMA), backfat thickness (BFT), rump fat thickness (RFT), and for marbling score (MARB), respectively, were used for the analyses. Moderate to high heritability estimates were obtained and ranged from 0.16 ± 0.03 (RFT) to 0.33 ± 0.05 (MARB). A high genetic correlation was observed between BFT and RFT (0.97 ± 0.02), suggesting that a similar set of genes affects both traits. The most relevant genomic regions associated with LMA, BFT, RFT, and MARB were found on BTA10 (5.4–5.8 Mb), BTA27 (25.2–25.5 Mb), BTA18 (60.6–61.0 Mb), and BTA21 (14.8–15.4 Mb). Two overlapping genomic regions were identified for RFT and MARB (BTA13:47.9–48.1 Mb) and for BFT and RFT (BTA13:61.5–62.3 Mb). Candidate genes identified in this study, including PLAG1, LYN, WWOX, and PLAGL2, were previously reported to be associated with growth, stature, skeletal muscle growth, fat thickness, and fatty acid composition. Our results indicate that ultrasound-based carcass and meat quality traits in the Montana Tropical® Composite beef cattle are heritable, and therefore, can be improved through selective breeding. In addition, various novel and already known genomic regions related to these traits were identified, which contribute to a better understanding of the underlying genetic background of LMA, BFT, RFT, and MARB in the Montana Tropical Composite population.

Single nucleotide polymorphisms at heat shock protein 90 gene and their association with thermo-tolerance potential in selected indigenous Nigerian cattle.

Heat shock protein (HSP) 90 gene provides protection and adaptation to thermal assault and certain polymorphisms have been associated to heat tolerance in humans and animals. Single nucleotide polymorphisms (SNPs) of HSP 90 gene were used to evaluate the scientific basis of heat tolerance in four zebu breeds of Nigeria. The DNA was extracted from skin tissue of 90 adult bulls representing White Fulani (WF), Sokoto Gudali (SG), Red Bororo (RB), and Ambala (AM). The SNPs were determined in DNAs using PCR, sequencing, and visualization and bio-editing by chromatogram in SeqMan Ngen tool. Subsequently, respective genotypes were constructed and genotypic and allelic frequencies were computed. Also, body parameters related to heat stress (HS) including body temperature (BT), rectal temperature (RT), and respiratory rates (RR) were taken for each animal before biological sampling and heat tolerance coefficient (HTC) was calculated. We detected four SNPs distinct/specific for each breed as follows: change from thymine (T) to guanine (G) at position 116 (T116G) in RB, G to cytosine (C) at 220 (G220C) in SG, G to adenine (A) at two positions, 346 (G346A) and 390 (G390A) in AM and WF, respectively. Heterozygous SNPs showed significantly lower values (P < 0.0001) for BT, RT, RR, and HTC than homozygous genotypes at all positions. We hypothesize that animals with heterozygous SNPs in exon 3 of HSP 90 may be tolerant to HS. These SNPs can be used as bio-markers for screening large populations of cattle for tolerance to hot tropical conditions in Nigeria and other sub-humid places.

Genetic potential of Sindhi cattle for A2 milk production

ContextCow milk is consumed in many countries. However, its consumption can be associated with gastrointestinal disorders in humans. The genetic profile of β-casein is one of the factors responsible for these disorders and the A1 variant is a causal agent. The β-casein A1 leads to the formation of bioactive peptides, which trigger intestinal reactions. The same is not observed for the A2 allele. A2 milk is obtained from cows with the A2A2 genotype. The identification of breeds and selection of animals for A2 milk production is important for public health and animal production. The Sindhi cattle (Bos taurus indicus) possesses characteristics such as adaptation to hot climate, resistance to parasites and utilisation of low-quality forage that are important for rearing in the tropics. AimsThe objective of the present study was to genotype the single-nucleotide polymorphism (SNP) that forms A1 and A2 alleles of the β-casein in Sindhi cattle. MethodsIn total, 348 Sindhi animals were used. DNA was extracted from hair follicles and submitted to PCR-sequencing for genotyping. Key resultsAllele frequency for A2 was 0.94 and for A1 it was 0.06. Genotype frequencies were 0.90 (A2A2), 0.09 (A1A2) and 0.01 (A1A1). The frequency of the A2A2 genotype in Sindhi cattle was similar to or higher than those found in zebu breeds and higher than those reported for specialised taurine breeds. ConclusionsThis high frequency of the A2A2 genotype indicates a genetic potential of the breed for A2 milk production and easy, assisted selection (if that is the intention). ImplicationsThis information gives importance to the breed and permits to add value to dairy product derived from it. It may increase producer’s income through producing and marketing A2 milk.

Effects of soybean meal versus processed whole soybean diets on the performance of young bulls and the fatty acid composition of intramuscular fat

Context It is hypothesised that the use of processed soybean for feedlot beef cattle improves feed efficiency and produces beef with a better fatty acid profile for human health. Aims This study aimed to evaluate average daily gain, feed efficiency, carcass traits, chemical composition, fatty acid profile and colour in the beef of young bulls fed diets with ground or extruded soybean. Methods A total of 60 young Zebu bulls (Nellore or Nellore crossed with other Zebu breeds) with an average initial liveweight of 320 ± 8.12 kg and an average initial age of 20 ± 2 months were randomly assigned to receive one of the following diets for 84 days: dehulled and defatted soybean meal (3.22% of ether extract), ground soybean (6.51% of ether extract) or extruded soybean (6.37% of ether extract). The fatty acid profiles of these animals were analysed using high-resolution gas chromatography. The CIE L*a*b* colour space model was used to numerically describe the colour during the aging period (0, 7, 14 and 21 days). Key results Diet had no effect on the average daily gain, feed efficiency or carcass traits of the animals (P &amp;gt; 0.05). Protein, ether extract and ash composition of the Longissimus lumborum (LL) muscle were not affected (P &amp;gt; 0.30) by the use of processed soybean grains. The ground soybean diet decreased oleic acid and C18:2 c9, t11 concentrations, but increased C18:2 t10, c12 and trans-octadecenoic acid isomer concentrations in the LL muscle compared with those in the dehulled and defatted soybean meal and extruded soybean diets (P &amp;lt; 0.05). Muscle from bulls fed processed soybean exhibited greater concentrations of stearic acid and saturated fatty acids, and a lower concentration of unsaturated fatty acids, as well as a decreased unsaturated fatty acids:saturated fatty acids ratio (P &amp;lt; 0.05). Processed soybean grains did not affect (P &amp;gt; 0.05) the LL muscle pH or colour. Conclusions The use of ground or extruded soybean did not affect the performance, carcass traits, LL protein, ether extract or ash composition, and had no impact on beef colour compared with the diet containing soybean meal. Processed whole soybeans in the diet did not increase unsaturated fatty acids or conjugated linoleic acid in beef compared with a diet without soybean meal. Implications Up to 20% of ground or extruded soybean in feedlot beef cattle can be used as a replacement for soybean meal and corn.