Search

Context: Animal husbandry in thermally stressful environments can be both complex and difficult, and the anticipated effects of climate change are expected to increase this condition. Aim: Thermoregulatory responses, and acid–base and electrolytic balance were evaluated in indigenous ewes of different coat colour during different moments of natural heat stress. Methods: Fifteen ewes of different colour (white, red and black; five of each) were used and data were collected for six consecutive weeks in the dry and rainy periods at three times of the day [(Moment 1) 0500 hours to 0600 hours; (Moment 2) 1200 hours to 1300 hours; and (Moment 3) 1700 hours to 1800 hours)]. Thermoregulatory (clinical measures), acid–base and electrolytic variables (blood examinations) were recorded. Air temperature and relative humidity were measured, and the radiant heat load was calculated. Key results: Black ewes showed higher averages of respiratory rate (RR) and rectal temperature (RT). RT was different between before and after heat stress for all ewes, while the RR was not affected and cutaneous evaporation presented minor variations. Between 1200 hours and 1300 hours, there was an increase in the hydrogen potential, oxygen pressure, oxygen saturation and total carbon concentration averages, and a decrease in partial pressure of carbon dioxide for all ewes. The base excess was not significantly different for each time of the day between the periods, and were not affected by the time of the day or the season. White ewes were highly affected by the time of the day and the period regarding electrolytic parameters, followed by the red ewes and black ewes. The first two discriminant functions showed that ewes, regardless of coat colour, show similarity in the animal responses at Moments 1 and 3, compared with Moment 2. RT was the main variable that distinguished the three genetic groups. Conclusions: Indigenous ewes of different coat colour recover physiological equilibrium after heat challenges. These adjustments enable them to maintain thermoregulatory responses, and acid–base and electrolytic balance within the physiological equilibrium. Implications: These variations indicated the ability of Brazilian indigenous ewes of different coat colour to recover thermoregulatory, and acid–base and electrolytic balance after an environmentally challenging condition in an equatorial semi-arid region, regardless of the period. The Morada Nova breed is an important animal genetic resource created by sheep farmers in the Brazilian semi-arid region. This breed has three genotypes: white, black and red. Our investigation sought to understand the thermoregulatory, acid–base and electrolytic dynamics of these genotypes according to the time of the day (morning, noon and end of the day) in the rainy and dry periods. All genotypes were able to return to homeothermy at the end of the day, regardless of the period [ABSTRACT FROM AUTHOR]

Tropical ewes of the Morada Nova breed were used to evaluate concordance on the effects of body condition score (BCS) and age classification using canonical discriminant analysis (CDA) as the classification method. The dependent variables in this study were: physiological responses, thyroid hormones, hematological and biochemical parameters. The hypothesis of this study was that the effect of BCS and age classification of the ewes might explain changes in physiological responses, thyroid hormones, hematological and serum biochemical parameters; however, very little effect was observed. Only the physiological responses and the thyroid hormones presented a subtle change using the BCS classification effect. An elevated error rate with both effects was observed, especially for age. However, the lowest total error rate was detected when all variables for BCS and for the thyroid hormones according to chronological age were used in the analyses. Therefore, the results do not support the recommendation of using BCS and age as classification effects, and therefore other effects should be used to improve reference ranges. [ABSTRACT FROM AUTHOR]

There are few animal germplasm/gene bank collections in Brazil, and basic studies are needed to attend the future internal and external demands from international partners. The aim of this work was to validate a “proof of concept” that integrates spatial (georeferenced data) and genetic data regarding the local of origin from 3518 DNA samples from 17 different genetic groups or breeds of sheep in the Brazilian Germplasm bank. Spatialisation shows that not all genetic groups have samples in the bank, and collection is concentrated in the conservation nuclei spread nationwide. Only 21% of states with a specific breed have samples in the gene bank. The mean number of animals sampled per collection was 32, while the mean distance travelled to collect samples was 262 km from the conservation nuclei. For example, the Brazilian Somali were only collected in the conservation nucleus in Ceará State. No samples were collected to date for the Cariri breed, which is recognised by the Brazilian Ministry of Agriculture. Only two farms and one breed in the bank are from the northern region. Of the 27 states, there are samples in the gene bank of sheep from 13, so several states have no samples, requiring collection from herds outside the official system of conservation to make sure that studies using this germplasm realised are not biased. Significant genetic differences are seen above 332 km, which should guide future sampling efforts. Suggestions are given for improving the quantity, quality and diversity of samples in the gene bank. [ABSTRACT FROM AUTHOR]

The implementation of sustainable breeding programs requires genetic breeding strategies that are appropriate for the reality production systems. It is also essential that the choice of animal selection criteria be based on breeders' knowledge and objectives. This work is an ethno-zootechnical study of the Morada Nova sheep breed and its crossbreeds. The goals of this study were to register and analyze indigenous breeders' knowledge and practices regarding animal selection criteria and to generate technical information to support a participatory breeding program of the breed. This study was conducted in the Morada Nova municipality in the state of Ceará, Brazil. Semi-structured interviews were evaluated using two groups of individuals, purebred Morada Nova sheep breeders (RMN, n = 13) and breeders of Morada Nova crossbreeds (MMN, n = 48). Interview questions were used to identify local selection criteria adopted by each group in the choice of animals for breeding. Data from the interviews were submitted to frequency distribution analysis and the Shapiro-Wilk test to verify their distribution. Later, the Kruskal-Wallis test was used to compare the two groups of farmers based on that information, in addition to multivariate statistical analysis and evaluation of Smith salience index. Breeders in the RMN group used selection criteria related to breed standards, such as pelage color. In contrast, breeders of the MMN group used criteria related to productivity, such as body conformation and milk production. Breeders should be engaged in the development of breeding programs, and it is important to consider their preferences and objectives when evaluating breeding animals. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the genetic parameters for the ability of a sheep to rank among the top three in its age category (ABI3) and for its total score (TS) on the judgement championships held in different agricultural fairs in Brazil. Data files included 3180 records referring to 1896 animals for ABI3 and 4383 records referring to 2170 animals for TS. The relationship matrix was composed by 4069 animals. Variance components were estimated fitting threshold and linear animal models for ABI3 and TS, respectively, by Bayesian analysis using the Gibbs sampler. The posterior means of the heritability and repeatability were, respectively, 0.10 ± 0.07 and 0.57 ± 0.11 for ABI3 and 0.12 ± 0.04 and 0.31 ± 0.02 for TS. The low values for the heritabilities related to these traits reveal a strong influence of the environmental factors, as the differential management offered to the animals before and during the fair. The repeatability values for ABI3 suggest high correlation among the animal classifications in different fairs. However, for TS, the observed performance has moderate confidence to be repeated over time. We conclude that although reduced, there is genetic variability for the animal’s performance in agricultural fairs. Nevertheless, due to the low heritability estimates, the expected response to direct selection for ABI3 and TS will be low. [ABSTRACT FROM PUBLISHER]

Copyright of Acta Scientiarum: Animal Sciences is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The first registers of Somali sheep in Brazil are from the beginning of the 1900s. This breed, adapted to the dry climate and scarce food supply, is restricted in the northeast region of the country. Molecular marker technologies, especially those based on genotyping microsatellite and mtDNA loci, can be used in conjunction with breeding (pedigree analysis) and consequently the maintenance of genetic variation in herds. Animals from the Brazilian Somali Conservation Nuclei from Embrapa Sheep and Goats in Ceará State were used to validate genetic monitoring by traditional pedigree methods and molecular markers. Nineteen microsatellite markers and 404 base pairs from the control region of mtDNA were used. For total herd diversity, an average 5.32 alleles were found, with expected heterozygosity of 0.5896, observed heterozygosity of 0.6451, 0.4126 for molecular coancestrality, and coefficient of inbreeding ( F) was −0.095. Comparing molecular coancestrality means over the years, there was a consistent increase in this parameter within the herd, increasing from 0.4157 to 0.4769 in 2 years (approx. 12% variation). Sixteen mtDNA haplotypes were identified. Inbreeding and other estimates from genealogical analyses confirm the results from molecular markers. From these results, it is possible to state that microsatellites are useful tools in genetic management of herds, especially when routine herd recording is not carried out, or there were gaps in recent generations. As well as pedigree control, genetic diversity can be optimized. Based on the results, and despite herd recording in the herd of Brazilian Somali of Embrapa Sheep and Goats, additional management measures need to be carried out in this herd to reduce inbreeding and optimize genetic variation. [ABSTRACT FROM AUTHOR]