Zebu Breeds Research Articles

Productive and economic performance of endemic N’Dama cattle in southern Mali compared to Fulani Zebu and their crossbreds

In recent decades, there has been a rapid shift in livestock breeds used in developing countries, leading to a loss of local genetic resources. The introduction of high-performing livestock breeds might, however, offer opportunities to improve the income of poor livestock keepers. In southern Mali, where cattle play an important role in farmers’ livelihoods, the endemic trypanotolerant N’Dama cattle breed is increasingly being crossbred with the improved Fulani Zebu breed. Thus, the N’Dama cattle face serious threats of genetic erosion, despite their adaptive attributes. This study aims to evaluate and compare the productive and economic performance of endemic N’Dama, Fulani Zebu and their crossbreds in southern Mali in order to assess the comparative advantages of these breed groups for farmers. Data collection methods comprised of interviews with 34, 31, 34 and 61 households keeping N’Dama, crossbreds, Fulani Zebu and mixed herds respectively, and a cow progeny history and body condition scoring (BCS) (n = 770). Data were analyzed using linear mixed models and a non-parametric test. Results on cow individual performances showed a higher body condition for N’Dama compared to Fulani Zebu and crossbred cattle, while cow milk offtake was higher for Fulani Zebu herds. Calving and offtake rates were higher for the Fulani Zebu and crossbred herds. The gross margin/cattle and the benefit-cost ratio were highest in the Fulani Zebu herds, followed by the crossbred herds, whereas the net benefit/cattle, including non-market benefits, such as traction, manure, insurance and home consumption, was similar between the herd categories. The N’Dama cattle remain a valuable breed for subsistence-oriented crop-livestock farmers for whom non-market benefits from cattle play a considerable role. Fulani Zebu and crossbred cattle were the most favorable options for market-oriented local and settled transhumant farmers, given their higher price and increased profitability.

Signatures of Selection From Candidate Gene Polymorphisms Panel in Five Zebu Breeds

ABSTRACT The signals of selection using candidate genes polymorphism were studied in five zebu breeds of Mexico. Three loci from GHRH and complementarily Steroyl Co Desaturase F762, Dopamine Beta Hydroxilase 17299, and LEP3272 were identified under selection. Findings depict Zebu selection pressure mainly on Brahman breed resulting in a divergent structure pattern.

Metabolic Heat Production and Methane Energy Loss in Growing Zebu and Crossbred Cattle under Tropical Climatic Condition

Indirect calorimetry is used to estimate metabolic heat production and methane energy loss from Tharparkar and Karan Fries (Holstein Friesian × Tharparkar) cattle in tropical climate by putting the animals in respiration calorimeter chamber. In the present study, Concentration of CH4, O2 and CO2 were measured in ambient air as well as in outlet air from the chamber by keeping the animals inside them. The data were recorded after 1 hours of feeding continuously for 6 hours at the interval of 1 minute for five days to decrease the random error. Physiological responses i.e. respiration rate and heart rate was significantly whereas rectal temperature was non significantly higher in Karan Fries as compared to Tharparkar cattle. Metabolic heat production and methane emission was significantly higher in Karan Fries (9.43 kcl/min & 122.93 L/day) than Tharparkar (4.72 kcal/min & 40.01 L/day) respectively. The finding of study showed the better adaptability of zebu breeds to tropical climatic condition in terms of metabolic heat and methane production as compared to crossbred cattle.

Genetic parameters for stayability to consecutive calvings in Zebu cattle

Longer-lived cows tend to be more profitable and the stayability trait is a selection criterion correlated to longevity. An alternative to the traditional approach to evaluate stayability is its definition based on consecutive calvings, whose main advantage is the more accurate evaluation of young bulls. However, no study using this alternative approach has been conducted for Zebu breeds. Therefore, the objective of this study was to compare linear random regression models to fit stayability to consecutive calvings of Guzerá, Nelore and Tabapuã cows and to estimate genetic parameters for this trait in the respective breeds. Data up to the eighth calving were used. The models included the fixed effects of age at first calving and year-season of birth of the cow and the random effects of contemporary group, additive genetic, permanent environmental and residual. Random regressions were modeled by orthogonal Legendre polynomials of order 1 to 4 (2 to 5 coefficients) for contemporary group, additive genetic and permanent environmental effects. Using Deviance Information Criterion as the selection criterion, the model with 4 regression coefficients for each effect was the most adequate for the Nelore and Tabapuã breeds and the model with 5 coefficients is recommended for the Guzerá breed. For Guzerá, heritabilities ranged from 0.05 to 0.08, showing a quadratic trend with a peak between the fourth and sixth calving. For the Nelore and Tabapuã breeds, the estimates ranged from 0.03 to 0.07 and from 0.03 to 0.08, respectively, and increased with increasing calving number. The additive genetic correlations exhibited a similar trend among breeds and were higher for stayability between closer calvings. Even between more distant calvings (second v. eighth), stayability showed a moderate to high genetic correlation, which was 0.77, 0.57 and 0.79 for the Guzerá, Nelore and Tabapuã breeds, respectively. For Guzerá, when the models with 4 or 5 regression coefficients were compared, the rank correlations between predicted breeding values for the intercept were always higher than 0.99, indicating the possibility of practical application of the least parameterized model. In conclusion, the model with 4 random regression coefficients is recommended for the genetic evaluation of stayability to consecutive calvings in Zebu cattle.

Estimates of repeatability and correlations of hemoparasites infection levels for cattle reared in endemic areas for Rhipicephalus microplus

Rhipicephalus microplus is a vector of cattle tick fever, a disease caused by the protozoans Babesia bovisand B. bigemina, and also anaplasmosis, produced by the Rickettsiales Anaplasma marginale. These tick-borne pathogens cause considerable losses to Brazilian livestock breeders and represent an obstacle to the expanded use of taurine breeds due to their higher sensitivity to ticks and hemoparasites compared to zebu breeds. Differences in the susceptibility to hemoparasites were also verified within breeds, suggesting that may be possible to select a most resistant phenotype. Therefore, repeatability of R. microplus counts and copy number of hemoparasites DNA were estimated, along with correlations between themselves, aiming to verify if those measures can be used as parameters to classify animals according to their parasite resistance degrees. Forty-two Canchim females kept on pastures naturally infested by ticks were evaluated for the level of infestation by R. microplus and infection by B. bovis, B. bigemina, and A. marginale. Twenty-four evaluations were performed once a month, for adult female ticks counts and blood samplings. The experimental period was divided into four phases, according to the animals age range: Phase 1: 8 to 13 months (collections 1 to 6); phase 2: 14 to 19 months (collections 7 to 12); phase 3: 20 to 25 months (collections 13 to 18), and phase 4: 26 to 31 months (collections 19 to 24). Blood samples were submitted to absolute quantification of hemoparasites DNA sequences using qPCR. The hemoparasite and tick counts data were transformed for normalization and were analyzed using mixed models. Among three species of hemoparasites studied, A. marginale presented the highest level of infection. During phase 3, B. bigemina presented higher infection levels (p < 0.05) compared to B. bovis, whereas no differences were observed in other phases. Estimated repeatabilities for parasite infection levels varied from low to moderate during our experiment. There were low correlations between tick counts and parasite infection levels, and between parasite infection levels from different species by themselves. Based on these results, under conditions of the present study, we suggest that it is possible to identify animals presenting a most resistant phenotype against infection by both hemoparasites and ticks. Moreover, the animal age may be an important factor related to resistance against these pathogens. The data obtained shed more light on the resistance to hemoparasites studied.

Effect of breed and feeding strategy on the eating quality of Kenyan beef

In Kenya, most of the livestock are reared on grass using extensive pastoral systems. Nevertheless, intensive feed-lot systems to finish beef cattle have become popular among local producers. The two systems are likely to have a different impact on the eating quality of beef, because quality is determined by the combined effects of breed, nutrition and management. The effect of free-range and semi-feed lot feeding strategies on the eating quality of beef from Zebu and Sahiwal breeds was assessed. A 2 x 2 between subjects factorial design was used (two breeds fed using two feeding strategies). From each single breed and feeding strategy combination, seven cattle were selected after three months of feeding. The cattle were slaughtered and their rump steaks sampled. The samples were frozen for 24 h then thawed for 4 h prior to analysis. The steaks’ pH was measured after cooking. They were then subjected to Texture Profile Analysis (TPA), ‘Warner-Bratzler’ Shear (WBS) tests, and organoleptic evaluations. The pH did not differ significantly with feeding strategy or breed ( P ≥0.05). The result from TPA and WBS revealed that semi feed-lot Sahiwal beef was tender than free-range Sahiwal beef ( P <0.05). On the other hand, there was no difference in tenderness between feed-lot and free-range Zebu beef ( P ≥0.05). An analysis between the breeds showed that feed-lot Sahiwal beef was tender than feed-lot Zebu beef ( P <0.05), but there was no difference in tenderness between beef from free-range Sahiwal and free-range Zebu ( P ≥0.05). In the sensory analysis, there was a significant difference for each of the sensory parameters ( P <0.05, each). Steaks from semi-feed lot Sahiwal were preferred to the other beef steaks. In conclusion, a semi-feed lot feeding strategy has the potential to improve the eating quality of beef from Sahiwal breed. Nevertheless, the improvement in the eating quality observed with Zebu breed, although not statistically significant, gives an opportunity for value chain actors to explore other management systems that can be combined with those assessed in this study to improve eating quality. Keywords: Beef, rump steak, eating quality, Sahiwal, Zebu, feed lot, pastoral, Kenya

Genetic diversity, population structure, and correlations between locally adapted zebu and taurine breeds in Brazil using SNP markers.

Genetic diversity is one of the most important issues in studies on conservation of cattle breeds and endangered species. The objective of this study was to estimate the levels of genetic differentiation between locally adapted taurine (Bos taurus taurus) and zebu (Bos taurus indicus) breeds in Brazil, which were genotyped for more than 777,000 SNPs. The fixation index (F ST), principal component analysis (PCA), and Bayesian clustering were estimated. The F ST highlighted genetic differentiation between taurine and zebu breeds. The taurine lines, Caracu and Caracu Caldeano, had significant genetic differentiation (F ST close to 5%) despite their recent selection for different uses (meat and milk). This genetic variability can be used for conservation of locally adapted animals, as well as for breeding programs on zebu breeds. Introgression of zebu in locally adapted breeds was identified, especially in Curraleiro Pé-Duro breed. The Gyr breed, however, had low breed purity at genomic level due to its very heterogeneous mixing pattern.

Contemporary groups in the genetic evaluation of Nellore cattle using Bayesian inference

Abstract: The objective of this work was to evaluate the criteria for the formation of contemporary groups (CGs) in the genetic evaluation of body weight at weaning in Nellore cattle. A total of 713,474 records from 3,066 herds located in Midwestern and Northern Brazil were used. Data were obtained from the genealogical registry of zebu breeds of the Brazilian association of zebu breeders. Data structures were defined based on the number of standard deviations (SDs) for outlier removal (±2.0, ±2.5, ±3.0, and ±3.5) and on the minimal number of animals per CG (3, 7, and 15). Genetic evaluation was performed with an animal model using Bayesian inference. Data structures with ±3.5 SDs and CG with at least 15 animals presented the highest additive genetic variance (82.65±2.93), and those with ±2.0 SDs and CG with at least 3 animals showed the lowest one (60.23±1.96). The proper formation of CGs results in better-quality data archives, allowing to obtain more trustable estimates for the genetic parameters. Better selection responses are obtained when the following criteria are adopted for the removal of outliers: 2.5, 3.0, and 3.5 standard deviations and a minimum of 15 animals per contemporary group.

Identification of SNP variations and different microRNA binding sites at 3-UTR region of bovine HSP90AA1 gene among different Indian breeds of cattle

Present study was aimed to identify mutations/SNPs and predict microRNAs within the 3-untranslated region of bovine Hsp90 AA1 gene. A total of 28 mutations were identified in the 3-untranslated region of bovine Hsp90 gene among 4 indigenous zebu breeds and 1 crossbred population. Results revealed that, natural mutational changes are more in crossbred cattle compared to indigenous zebu animals and the difference was statistically significant. Prediction of microRNA binding site revealed that there are atleast 7 different micro RNAs, which may interact at 3-untranslated region of bovine Hsp90AA1 gene among different breeds of cattle investigated. Out of the 7 microRNAs, miR8882 and miR3796 were the most commonly distributed among the 4 breeds while the miR9491and miR-2277-5p were restricted to Gir and Ongole breeds respectively. While miR8882 binding site were unanimous, miR3796 showed variation among the breeds. This indicate that there exists differences in the microRNA binding sites of the 3-untranslated region among cattle breeds.

Genomewide association mapping and pathway analysis of meat tenderness in Polled Nellore cattle1

Brazil is one of the world's largest beef exporters, although the product has a low price due to quality issues. The meat exported by Brazil is considered medium and low quality by international buyers, mainly due to lack of tenderness. The predominant Zebu breeds (80% Nellore) are known for producing tougher beef than taurine breeds. Nonetheless, some studies have shown that there is substantial genetic variability for tenderness within the Nellore breed, although it is a difficult trait to improve by conventional selection methods. Therefore, the aim of this study was to perform a genomewide association study (GWAS) and a gene set enrichment analysis to identify genomic regions and biologically relevant pathways associated with meat tenderness in Polled Nellore cattle. Data consisted of Warner-Bratzler shear force values of LM from 427 Polled Nellore animals divided into 3 experimental slaughters (years 2005, 2008, and 2010). The animals were genotyped with either the Illumina BovineHD BeadChip (777k, on 61 samples) or the GGP Indicus HD chip (77k, on 366 samples). Single nucleotide polymorphisms were excluded when the call rate was <90%, the Hardy-Weinberg proportions -value was <1% (Fisher exact test, Bonferroni adjusted), and the minor allele frequency was <1%. Imputation from the GGP Indicus HD chip to the Illumina BovineHD BeadChip was performed using the FImput program. Genomewide association analysis was performed using the Efficient Mixed Model Association eXpedited (EMMAx) and the population parameters previously determined (P3D) methods. The GWAS was complemented with a gene set enrichment analysis performed using the FatiGO procedure. Significant markers ( < 0.0001) explaining a larger proportion of variation than other significant SNPs were located on chromosomes 3, 13, 17, 20, 21, and 25, indicating QTL associated with meat tenderness throughout the genome. Additionally, gene set analysis identified 22 Gene Ontology functional terms and 2 InterPro entries that showed significant enrichment of genes associated with tenderness. The functional categories included protein tyrosine and serine/threonine kinase activity, calcium ion binding, lipid metabolic process, and growth factors, among others. These results help to elucidate the genetic architecture and metabolic pathways underlying this trait, which is of extreme economic and social importance to Brazil, because Nellore is the dominant beef cattle breed in the country.

Genome-Wide Association Study for Carcass Traits in an Experimental Nelore Cattle Population.

The purpose of this study was to identify genomic regions associated with carcass traits in an experimental Nelore cattle population. The studied data set contained 2,306 ultrasound records for longissimus muscle area (LMA), 1,832 for backfat thickness (BF), and 1,830 for rump fat thickness (RF). A high-density SNP panel (BovineHD BeadChip assay 700k, Illumina Inc., San Diego, CA) was used for genotyping. After genomic data quality control, 437,197 SNPs from 761 animals were available, of which 721 had phenotypes for LMA, 669 for BF, and 718 for RF. The SNP solutions were estimated using a single-step genomic BLUP approach (ssGWAS), which calculated the variance for windows of 50 consecutive SNPs and the regions that accounted for more than 0.5% of the additive genetic variance were used to search for candidate genes. The results indicated that 12, 18, and 15 different windows were associated to LMA, BF, and RF, respectively. Confirming the polygenic nature of the studied traits, 43, 65, and 53 genes were found in those associated windows, respectively for LMA, BF, and RF. Among the candidate genes, some of them, which already had their functions associated with the expression of energy metabolism, were found associated with fat deposition in this study. In addition, ALKBH3 and HSD17B12 genes, which are related in fibroblast death and metabolism of steroids, were found associated with LMA. The results presented here should help to better understand the genetic and physiologic mechanism regulating the muscle tissue deposition and subcutaneous fat cover expression of Zebu animals. The identification of candidate genes should contribute for Zebu breeding programs in order to consider carcass traits as selection criteria in their genetic evaluation.

Polymorphism in the Beta Casein Gene and analysis of milk characteristicsin Gir and Guzerá dairy cattle.

Several human health problems have been related to the allergenic constitution of bovine milk due to the body's immune reaction to milk proteins. It is necessary find solutions to minimize the occurrence of such reactions, given the importance of milk as a source of animal protein. The aim of this study was to evaluate the allelic frequency of the CSN2 gene and to evaluate differences in the characteristics of Gir and Guzerá bovine milk. One hundred and fifty-six cows were used (68 Gir and 88 Guzerá) from the Felipe Camarão Experimental Station herd of the Agricultural Research Corporation of RN (EMPARN). DNA extractions were carried out from hair follicles of the animals; the gene was then amplified and sequenced in an ABI 3100 automatic sequencer. The obtained sequences were submitted to analysis using the Geneious 5.6.5® program. Data were submitted to analysis of variance and to the Tukey-Kramer test at 5% probability and cluster analyses by main components were performed. Allele frequencies were 98 and 97% for the A2 allele and 0.96 and 0.93% for the genotype A2A2 for Gir and Guzerá, respectively. Gir and Guzerá animals showed differences in protein, lactose, and non-fat dry extract levels. Although correlations between milk yield and the production and some milk components are moderate, increases in milk yield are always greater than the increase in constituent yield. In addition, even though Guzerá animals have a higher percentage of protein, lactose, and non-fat dry extract, milk from Zebu breeds is an alternative for individuals sensitive to β-casein protein.

Bovine Mastitis and Risk Factors in Small Holder Lactating Dairy Farms in Hawassa, Southern Ethiopia

A cross sectional study was conducted from November 2008 to April 2009 in Hawassa town, southern Ethiopia to determine the overall mastitis prevalence and identify the role of potential risk factors in 183 randomly selected srnall holder lactating dairy cows of 53 high grade Holstein Friesian, 113 Holstein-indigenous zebu cross and 17 indigenous zebu breeds. Of the total 183 lactating smallholder 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 breeds was found not affected. Among the potential risk factors considered, breed ( = 17.3, P< 0.05), presence of teat lesion and/or tick infestation ( = 7.73, P< 0.05), stage of' lactation 22 ( =l3.8, P< 0.05) and parity number ( = l9.4, P< 0.05) had significant effect on the prevalence of subclinical 22

Genome-wide SNPs analysis of indigenous zebu breeds in Pakistan

Prospects of high throughput technology in animal genetics makes easy to investigate hidden genetic variation in farm animal?s genetic resources. However, many SNPs technologies are currently practicing in animal genetics. In this study, we investigated genome wide SNPs variations and its distribution across the indigenous cattle population in Pakistan using Illumina Bovine HD (777K) SNPs bead chip. A total of 136 individuals from ten different breeds were genotyped and after filtration 500, 939 SNPs markers were used for further analysis. The mean minor allele frequency (MAF) was 0.23, 0.20, 0.22, 0.22, 0.20, 0.18, 0.20, 0.22, 0.21 and 0.18 observed for Achi, Bhagnari, Cholistani, Dhanni, Dajal, Kankraj, Lohani, Red sindi, Sahiwal and Tharparkar cattle, respectively. Significant difference (P&lt;0.001) of MAFs were observed in selected population. A common variants minor allele frequency (?0.10 and? 0.5) was estimated (64%). Across all sampled populations 64% SNPs markers were observed polymorphic (MAF&gt;0.05) within breeds and remaining 36% were considered as monomorphic markers. Average observed (Ho) and expected (HE) heterozygosity values 0.662 and 0.640 were estimated among these breeds. In conclusion, this preliminary study results revealed that these SNPs variation level could potentially be used for genetic characterization of zebu cattle breeds and could also be used to estimate genetic potential of these cattle breeds for livestock improvement in country.

Factors affecting the selling prices of calves in auctions in Santa Catarina State, Brazil

The objective of this study was to investigate the effects of genetic group and calf sex on selling prices in auctions in the state of Santa Catarina (SC), Brazil. We evaluated 33,143 animals, representing 3,587 lots in 47 auctions from 2009 to 2014. The calves were classified according to genetic groups: British breed or crossbreed (BX); Continental breed or crossbreed (CX); Zebu breed or crossbreed (ZC); British and Continental crossbreed (BC); and Bos taurus and Bos indicus crossbreed (TI). The lots were composed of male and female calves. The years presenting low and high changes in the price of calves were similar to the variation in the price of beef cattle and, in 2014, the calf price reached its highest value (R$5.36). Male calves were sold at prices higher than female calves (average 7.8%), but this difference was driven by year of analysis, in which the closest approach occurred during periods of reduction in the price of live cattle in SC (2012 and 2013). Calves of genetic groups ZX and TI received, on average, lower prices (R$4.49 and R$4.64, respectively) compared with the other groups. In 2013, males from the BX group had greater variation in price compared with CX (3.9%) and BC (5.7%). On the other hand, female heifers from the BX group received higher average prices in 2011 compared with the CX, BC, IT, and ZX groups (8.1, 8.5, 14.7, and 16.5%, respectively). Recently, female British heifers have had a greater appreciation in auctions held in SC, possibly for their reproductive performance potential of beef cows. Thus, sex and different genetic groups are factors that impact the selling price of calves in the SC region.

Effect of the g.98535683A > G SNP in the CAST gene on meat traits of Nellore beef cattle (Bos indicus) and their crosses with Bos taurus

The objective of this study was to estimate allele frequencies of the g.98535683A>G:BTAU7 SNP in the CAST gene in different genetic groups of beef cattle produced in Brazil (Nellore and their crosses with Bos taurus), and to evaluate associations between this polymorphism and meat traits. Five hundred animals from six different genetic groups were genotyped and phenotyped for shear force (SF), myofibrillar fragmentation index (MFI), rib eye area, backfat thickness, and total lipids. Alleles A and G of the SNP were detected in all genetic groups and the frequency of A was higher than G. Significant association (P<0.05) was observed between the polymorphism and meat tenderness (SF and MFI), in which genotype AA exhibited the best values. These results demonstrate for the first time the occurrence of the studied SNP in a Zebu breed and its potential application to the genetic improvement of meat tenderness in the Nellore breed (Bos indicus) and its crosses with Bos taurus.

Fetal sex influence in the productive performance of dairy cows

Investigating factors that could affect milk production of cows is an important way to improve the efficiency of production systems. This purpose of this study was to verify and quantify the influence of calf sex on milk production and lactation length in herds of Holstein, Gir, and Guzera cows. Data from 10,780 lactations of 4,807 Holstein cows that calved between 2001 and 2013; 18,898 lactations of 13,172 Gir cows that calved between 1985 and 2013; and 5,277 lactations of 3,972 Guzera cows that calved between 1987 and 2013 were used. Both the accumulated 305-day milk yield (P305) and the length of the lactation period up to 305 days (DL305) were evaluated. Analysis of variance was performed by the least squares method using the GLM procedure in the SAS statistical program. The P305 was not influenced by the sex of the calf in the Holstein breed. However in the zebu breeds (Gir and Guzera), both P305 and DL305 were significantly affected (P &amp;lt; 0.01) by the sex of the calf, with higher production and average length of lactation in cows that calved males. In addition, a significant difference was also nested within sex of calf and age at first calving (P &amp;lt; 0.05) in the Gir breed. The results indicate that for the zebu breeds, calf sex influences production characteristics.

Genetic correlation estimates between beef fatty acid profile with meat and carcass traits in Nellore cattle finished in feedlot.

The objective of this study was to estimate the genetic-quantitative relationships between the beef fatty acid profile with the carcass and meat traits of Nellore cattle. A total of 1826 bulls finished in feedlot conditions and slaughtered at 24months of age on average were used. The following carcass and meat traits were analysed: subcutaneous fat thickness (BF), shear force (SF) and total intramuscular fat (IMF). The fatty acid (FA) profile of the Longissimus thoracis samples was determined. Twenty-five FAs (18 individuals and seven groups of FAs) were selected due to their importance for human health. The animals were genotyped with the BovineHD BeadChip and, after quality control for single nucleotide polymorphisms (SNPs), only 470,007 SNPs from 1556 samples remained. The model included the random genetic additive direct effect, the fixed effect of the contemporary group and the animal's slaughter age as a covariable. The (co)variances and genetic parameters were estimated using the REML method, considering an animal model (single-step GBLUP). A total of 25 multi-trait analyses, with four traits, were performed considering SF, BF and IMF plus each individual FA. The heritability estimates for individual saturated fatty acids (SFA) varied from 0.06 to 0.65, for monounsaturated fatty acids (MUFA) it varied from 0.02 to 0.14 and for polyunsaturated fatty acids (PUFA) it ranged from 0.05 to 0.68. The heritability estimates for Omega 3, Omega 6, SFA, MUFA and PUFA sum were low to moderate, varying from 0.09 to 0.20. The carcass and meat traits, SF (0.06) and IMF (0.07), had low heritability estimates, while BF (0.17) was moderate. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with BF were 0.04, 0.64 and -0.41, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with SF were 0.29, -0.06 and -0.04, respectively. The genetic correlation estimates between SFA sum, MUFA sum and PUFA sum with IMF were 0.24, 0.90 and -0.67, respectively. The selection to improve meat tenderness in Nellore cattle should not change the fatty acid composition in beef, so it is possible to improve this attribute without affecting the nutritional beef quality in zebu breeds. However, selection for increased deposition of subcutaneous fat thickness and especially the percentage of intramuscular fat should lead to changes in the fat composition, highlighting a genetic antagonism between meat nutritional value and acceptability by the consumer.

Multivariate characterization of morphological traits in West African cattle sires

Abstract. A total of 183 adult sires belonging to nine West African cattle breeds sampled in 67 villages of Mali, Burkina Faso and Benin were assessed for 16 body measurements and 18 qualitative traits. Within type of cattle (zebu, sanga or taurine), the different breeds analysed showed large differences in body measurements. In general, taurine breeds had lower average values than the zebu breeds while sanga cattle tended to have intermediate values. Principal component analysis identified three factors characterising body measurements. Factor 1 summarised the information provided by those traits characterising the size of the individuals and explained 59.0 % of the variability. Factor 2 tended to gather information characterising the body width and explained 8.0 % of the variation. Less representative, Factor 3 (6.6 % of the variability) had no clear interpretation. Qualitative traits did not allow to distinguish among either cattle groups or breeds. Two Correspondence Analysis Dimensions computed on qualitative traits (explaining 26.2 and 15.5 % of the variability, respectively) did not allow to differentiate between zebu, sanga or taurine cattle breeds. Our results confirm that, in the framework of a general appearance, body measurements are the main criteria for differentiating West African cattle breeds. Furthermore, the current research has not allowed to identify breeding preferences on qualitative type traits in West African cattle sires. Therefore, homogenisation of the appearance of individuals within cattle breed is not expected.

Inbreeding depression in Zebu cattle traits.

The productivity of herds may be negatively affected by inbreeding depression, and it is important to know how intense is this effect on the livestock performance. We performed a comprehensive analysis involving five Zebu breeds reared in Brazil to estimate inbreeding depression in productive and reproductive traits. Inbreeding depression was estimated for 13 traits by including the individual inbreeding rate as a linear covariate in the standard genetic evaluation models. For all breeds and for almost all traits (no effect was observed on gestation length), the performance of the animals was compromised by an increase in inbreeding. The average inbreeding depression was -0.222% and -0.859% per 1% of inbreeding for linear regression coefficients scaled on the percentage of mean (βm ) and standard deviation (βσ ), respectively. The means for βm (and βσ ) were -0.269% (-1.202%) for weight/growth traits and -0.174% (-0.546%) for reproductive traits. Hence, inbreeding depression is more pronounced in weight/growth traits than in reproductive traits. These findings highlight the need for the management of inbreeding in the respective breeding programmes of the breeds studied here.