Holstein heifers in desert climate: effect of coat color on physiological variables and prediction of rectal temperature.

Two hundred Holstein heifers were divided by hair coat color in black (n1 = 60), white (n2 = 62), and mixed (n3 = 78) to accomplish two objectives: (1) to compare physiological variables using an analysis of variance, and (2) to construct regression equations to predict rectal temperature. In each heifer, rectal temperature (RT), respiration frequency (RF), and body surface temperatures (obtained with infrared thermography in eye, nose, forehead, head, neck, ear, shoulder, flank, belly, leg, loin, rump, and vulva) were measured. Black heifers had more RF and RT (P < 0.01) than mixed and white coat heifers; white heifers had similar RT than mixed color heifers, but they exhibited less RF (P < 0.05). In general, black and mixed coat color heifers had higher BST (P < 0.01) than white heifers in the majority of the anatomical regions measured. For black coat heifers, the best regression model to predict RT included three predictor variables: [RT = 35.59 - 0.013 (RH) + 0.045 (RF) + 0.019 (TEar); R2 = 71%]. For white coat heifers, the best model included two predictor variables: [RT = 35.29 + 0.035 (RF) + 0.033 (TForehead); R2 = 71%]; and for mixed coat color heifers, the best model included two predictor variables: [RT = 35.07 + 0.022 (RF) + 0.038 (THead); R2 = 44%]. Heifers with dark hair coat color showed higher physiological constants than white heifers; the prediction of rectal temperature was more precise in heifers with well-defined hair coat color. Physiological and climatic variables, along with infrared thermography, represent an appropriate combination to predict rectal temperature in Holstein heifers with predominant white or black hair coat color.

Thermal features, ambient temperature and hair coat lengths: Limitations of infrared imaging in pregnant primitive breed mares within a year.

Infrared thermography is a non-invasive technique which allows to distinguish between pregnant and non-pregnant animals. Detecting accurate body surface temperatures can be challenging due to external factors altering thermograph measurements. This study aimed to determine the associations between the ambient temperature, the hair coat features and the temperatures of mares' abdomens. It compared pregnant and non-pregnant mares throughout 11 months. The research was carried out on 40 Konik Polski mares, which were divided into pregnant and non-pregnant groups. The temperature (Tmax, maximal; Taver, average; Tmin, minimal) of the mares' abdomen was evaluated in two regions of interest: the whole area of the lateral surface of the mares' abdomen (Px1) and the flank area of the lateral surface of mares' abdomen (Px2). During the increasing period, the slopes in the linear regression equation did not differ significantly for ambient (Tamb) and surface temperatures in both groups. In the decreasing period, the slopes did not differ significantly for Tamb and Tmax in the non-pregnant group. They also did not differ for Tamb and Taver in Px1 and Tamb and Tmin in Px1 in both pregnant and non-pregnant groups respectively. Other slopes varied significantly (p < .001). There was no evidence of parallel changes in hair coat features and measured temperatures. The flank area appears more suitable for thermal imaging in pregnant mares due to the seasonal fluctuations in hair coat lengths.

Relationship between thermal environment and morphophysiological, performance and carcass traits of Brahman bulls raised on tropical pasture: A canonical approach to a set of indicators.

The purpose of this study was to understand and discuss the relationships of the thermal environment, morphophysiological response, performance, and carcass traits of Brahman bulls from weaning at 18 months exposed to grazing conditions based on the physiological and evolutionary rationale behind the different proposals for the thermal adaptation of zebu cattle. Fifty-three uncastrated and clinically healthy bulls with birth and weaning weight of 34.0 ± 3.32 kg and 215.5 ± 44.75 kg, respectively, were evaluated. Fifteen canonical correlations were estimated, but only six were significant: thermal environment × thermoregulatory responses (rc = 0.4635; P = 0.0413); thermal environment × performance (rc = 0.4338; P = 0.0218); thermoregulatory responses × performance (rc = 0.5119; P = 0.0071); hair coat characteristics × performance (rc = 0.4939; P = 0.0273); hormone × carcass traits (rc = 0.5408; P = 0.0698); and performance × carcass traits (rc = 0.9644; P < 0.0001). Thermal environment, thermoregulatory responses and hair coat morphology influence of 18.81%, 21.49% and 24.40%, respectively, were found in the performance. We also concluded that (i) rectal temperature (RT) is a homoeothermic indicator; (ii) sweating rate (SR) is an important heat dissipation mechanism to explain the adaptation of zebu animals in the tropics and is related to weight at 550 days (W550); (iii) coat morphology, especially length (HL), diameter (HD) and hair density (ND) are related to animal performance; and (iv) hormonal profile, mainly T4, influences the carcass traits (yield, weight, subcutaneous fat and marble meat).

The curly coat phenotype of the Ural Rex feline breed is associated with a mutation in the lipase H gene.

Mutations in lipase H (LIPH) and lysophosphatidic acid receptor 6 (LPAR6), which are essential for the lysophosphatidic acid (LPA) signalling pathway, are associated with hypotrichosis and wooly hair in humans. Mutations in LPAR6 and keratin 71 (KRT71), result in unusual fur growth and hair structure in several cat breeds (Cornish Rex, Devon Rex and Selkirk Rex). Here, we performed target sequencing of the LIPH, LPAR6 and KRT71 genes in six cat breeds with specific hair-growth phenotypes. A LIPH genetic variant (LIPH:c.478_483del; LIPH:p.Ser160_Gly161del) was found in Ural Rex cats with curly coats from Russia, but was absent in all other cat breeds tested. In silico three-dimensional analysis of the LIPH mutant protein revealed a contraction of the α3-helix structure in the enzyme phospholipid binding site that may affect its activity.

A Study of Selected Physicomechanical and Histological Parameters of Hair Originating from Three Primate Species.

The aim of this study was to determine selected characteristics of hair originating from adult females of three primate species: lar gibbon, crested black macaque and common chimpanzee. The research material consisted of 300 hairs collected from the top of the head. The analysis included the length, diameter, strength, breaking load, elongation and cross-section area of the hairs, and the hair index. Additionally, the scale number per 1 mm of hair length was determined using scanning electron microscope images. Lar gibbon hairs were the thinnest and the longest, while common chimpanzee hairs were the thickest and the shortest, and concurrently the least resistant. Hairs from various primate species differ in terms of their morphological structure and histological features and thus can be used for differentiation and identification of species.

Added dietary vegetables and fruits improved coat quality of capybara in Seoul Zoo, Republic of Korea: A case study.

Adequate levels of dietary vitamin C are necessary for capybaras (Hydrochoerus hydrocharis) because they cannot synthesize the vitamin endogenously. Beginning in 2013, hair and weight loss, as well as general dermatitis, were observed in all individual capybaras (n = 4) in a mixed exhibit at Seoul Zoo. Seven additional vegetables, leafy greens, and fruits that increased dietary vitamin C concentration from ∼300-400 to >600 mg/kg dry matter were added to the diet since January 2015. Within 6 months, capybaras' skin and coats improved considerably, with hair becoming thicker and glossier. Animals visually appeared healthier and gained weight. In conclusion, hair loss, dermatitis, and weight loss in capybara can be improved by feeding enough fresh green leaves, vegetables, and fruits. Although vitamin C is considered a major factor for alleviation of poor body condition observed, increased status of other nutrients (i.e., vitamin B6 ) provided by the diet change may also have contributed to the improvements seen in the capybara. Zoo Biol. 36:50-55, 2017. © 2016 Wiley Periodicals, Inc.

Differences in the intestinal microbiota and association of host metabolism with hair coat status in cattle.

Introduction: The hair coat status of cattle serves as an easily observed indicator of economic value in livestock production; however, the underlying mechanism remains largely unknown. Therefore, the objective of the current study was to determine differences in the intestinal microbiota and metabolome of cattle based on a division of with either slick and shining (SHC) or rough and dull (MHC) hair coat in Simmental cows. Methods: Eight SHC and eight MHC late-pregnancy Simmental cows (with similar parities, body weights, and body conditions) were selected based on their hair coat status, and blood samples (plasma) from coccygeal venipuncture and fecal samples from the rectum were collected. The intestinal microbiota (in the fecal samples) was characterized by employing 16S rRNA gene sequencing targeting the V3-V4 hypervariable region on the Illumina MiSeq PE300 platform, and plasma samples were subjected to LC-MS/MS-based metabolomics with Progenesis QI 2.3. Plasma macromolecular metabolites were examined for differences in the metabolism of lipids, proteins, mineral elements, and hormones. Results: Notable differences between the SHC and MHC groups related to host hair coat status were observed in the host metabolome and intestinal microbiota (P < 0.05). The host metabolome was enriched in histidine metabolism, cysteine and methionine metabolism, and purine metabolism in the SHC group, and the intestinal microbiota were also enriched in histidine metabolism (P < 0.05). In the MHC group, the symbiotic relationship transitioned from cooperation to competition in the MHC group, and an uncoupling effect was present in the microbe-metabolite association of intestine microbiota-host interactions. The hubs mediating the relationships between intestinal microbiota and plasma metabolites were the intestinal bacterial genus g__norank_f__Eubacterium_coprostanoligenes_group, plasma inosine, triiodothyronine, and phosphorus, which could be used to differentiate cows' hair coat status (P < 0.05). Conclusion: Overall, the present study identified the relationships between the features of the intestinal microbiota and host hair coat status, thereby providing evidence and a new direction (intestine microbiota-host interplay) for future studies aimed at understanding the hair coat status of cattle.

Changes in Hair Coat Length and Diameter in Blanketed and Nonblanketed Adult Horses in the Winter.

Horses are often blanketed during cold weather for numerous reasons including assisting thermoregulation, cleanliness, and anecdotally to decrease hair coat length. However, the impact of blanketing on the hair coat has yet to be evaluated. The objective of this study was to evaluate changes in hair coat length and diameter over time in blanketed and nonblanketed horses during winter. In October 2019, 16 mature adult horses were blocked by breed and BCS and randomly assigned to a blanketed (n = 8) or nonblanketed (n = 8) treatment; blankets were placed. Data was collected between October 2019 and March 2020 in River Falls, WI. During this time BW, BCS, and hair coat samples were taken monthly. Twenty hair coat samples were taken from the nonmane side of the neck and the hindquarters using a tweezers and measured for the length and diameter using a digital micrometer and caliper, respectively. The average measurement was used to analyze the data. Horse neck and hindquarter hair were the longest and had the greatest diameter in January and February and they were the shortest with the smallest diameter in October and March regardless of treatment (P ≤ .05). Blanketed horses had shorter neck hair length when compared to nonblanketed horses in January at 43 and 58 mm, respectively, and February at 35 and 47 mm, respectively (P ≤ .05). These results suggest blanketing a horse can alter hair coat length, however, hair coat growth over time follows a similar pattern regardless of blanketing practices.

The Effect of the Season, the Maintenance System and the Addition of Polyunsaturated Fatty Acids on Selected Biological and Physicochemical Features of Rabbit Fur.

The aim of the study was to show the impact of environmental conditions and dietary supplementation with ethyl esters of linseed oil on the quality of the rabbit hair coat. The research was divided into 4 stages: laboratory (summer and winter) and outdoor (summer and winter). In each stage of the research, animals were divided into control and experimental groups. The animals were fed in accordance with the feeding standards of reproductive rabbits during the period of sexual dormancy. The rabbits from the experimental groups during the first two months were given an addition of ethyl linseed oil to the feed. In the experiment, linseed oil was cold-pressed directly in the laboratory. Three samples of hair were collected: before the study, after two months of treatment, and after two months from the end of supplementation. The hair coat biological properties, such as share of individual hair fractions (%), heat transfer index (HTI), hair diameter (µm), as well as physico-mechanical properties such as breaking force (N), breaking stress (kg/cm2) and elongation (%) were performed. Moreover, the histological structure of hair and histological hair evaluation were performed. The fatty acid profile was determined in the hair as well. The obtained results of the content of individual fatty acids were grouped into saturated fatty acids and unsaturated fatty acids. In addition, omega-3 and omega-6 were distinguished from the group of unsaturated acids. The environmental conditions have a major impact on the quality of the rabbit coat. The best results of hair thickness and their heat protection were obtained from animals kept outdoors. The studies did not show an influence of the administered preparation on the quality of the rabbit coat. The hair became thinner, but more flexible and tear-resistant. Administration of linseed oil ethyl esters had significant, beneficial changes in the fatty acid profile in hair and hair sebum were observed. There was a significant increase in omega-3 acids, and a significant decrease in the ratio of omega-6 to omega-3 acids.

Minimal Erythema Dose Determination in Holstein Friesian Cattle.

Cattle on pasture are continuously exposed to solar UV radiation, which has been associated with biological effects such as sunburn, photosensitization, squamous cell carcinoma, and cutaneous vitamin D3 production. The minimal erythema dose (MED) required to produce first-degree sunburn (erythema) is poorly researched in cattle. Since cattle are naturally covered with dense hair coats, the MED is influenced by the UV protection offered by the hair. The objective of this study was to determine the MED on intact-hair-covered (MED-H) and shaved white skin (MED-S) of Holstein Friesian cattle. Twenty-one Holstein Friesian cows and heifers were MED tested using a narrowband UV-B LED light (peak irradiance at 292 nm) on eight hair-covered and eight shaved areas over white skin previously unexposed to direct sunlight. Erythema was visually assessed after 24 h. The mean MED-H and MED-S were 5,595 and 329 J/m2, respectively. Heifers had a higher MED-H compared to cows, 7,600 and 4,969 J/m2, respectively. The mean UV transmittance of white cattle hair was 6.7%. MED-H was correlated with hair length (Spearman's rho = 0.76). A linear regression model showed that each millimeter of hair coat length increased the MED-H by 316 J/m2. In conclusion, this study provides a MED testing protocol for cattle and reports standardized values of MED for cattle on intact-hair-covered and shaved areas.

Comparison of the Surface Thermal Patterns of Horses and Donkeys in Infrared Thermography Images.

Infrared thermography (IRT) is a valuable diagnostic tool in equine veterinary medicine; however, little is known about its application to donkeys. This study aims to find patterns in thermal images of donkeys and horses and determine if these patterns share similarities. The study is carried out on 18 donkeys and 16 horses. All equids undergo thermal imaging with an infrared camera and measurement of the skin thickness and hair coat length. On the class maps of each thermal image, fifteen regions of interest (ROIs) are annotated and then combined into 10 groups of ROIs (GORs). The existence of statistically significant differences between surface temperatures in GORs is tested both "globally" for all animals of a given species and "locally" for each animal. Two special cases of animals that differed from the rest are also discussed. The results indicate that the majority of thermal patterns are similar for both species; however, average surface temperatures in horses (22.72±2.46 °C) are higher than in donkeys (18.88±2.30 °C). This could be related to differences in the skin thickness and hair coat. The patterns of both species are associated with GORs, rather than with an individual ROI, and there is a higher uniformity in the donkeys' patterns.

Demography and rapid local adaptation shape Creole cattle genome diversity in the tropics.

The introduction of Iberian cattle in the Americas after Columbus' arrival imposed high selection pressures on a limited number of animals over a brief period of time. Knowledge of the genomic regions selected during this process may help in enhancing climatic resilience and sustainable animal production. We first determined taurine and indicine contributions to the genomic structure of modern Creole cattle. Second, we inferred their demographic history using approximate Bayesian computation (ABC), linkage disequilibrium (LD) and N e Slope (NeS) analysis. Third, we performed whole genome scans for selection signatures based on cross-population extended haplotype homozygosity (XP-EHH) and population differentiation (F ST) to disentangle the genetic mechanisms involved in adaptation and phenotypic change by a rapid and major environmental transition. To tackle these questions, we combined SNP array data (~54,000 SNPs) in Creole breeds with their modern putative Iberian ancestors. Reconstruction of the population history of Creoles from the end of the 15th century indicated a major demographic expansion until the introduction of zebu and commercial breeds into the Americas ~180 years ago, coinciding with a drastic N e contraction. NeS analysis provided insights into short-term complexity in population change and depicted a decrease/expansion episode at the end of the ABC-inferred expansion, as well as several additional fluctuations in N e with the attainment of the current small N e only towards the end of the 20th century. Selection signatures for tropical adaptation pinpointed the thermoregulatory slick hair coat region, identifying a new candidate gene (GDNF), as well as novel candidate regions involved in immune function, behavioural processes, iron metabolism and adaptation to new feeding conditions. The outcomes from this study will help in future-proofing farm animal genetic resources (FAnGR) by providing molecular tools that allow selection for improved cattle performance, resilience and welfare under climate change.

Artificially extended photoperiod administered to pre-partum mares via blue light to a single eye: Observations on gestation length, foal birth weight and foal hair coat at birth.

In seasonally breeding animals, photoperiod perception is crucial for timing of important physiological events. In the horse, long day photoperiod influences the onset of ovulation and cyclicity, shedding of the heavier winter coat and the timing of parturition. In this compilation of studies, conducted across three breeding seasons and two countries, the impact of artificially extended day length was investigated on gestation length, foal birth weight and foal hair coat at birth. The light therapy was administered to pre-partum mares via mobile head worn masks which provided short wavelength blue light to a single eye. In Study 1, reductions in gestation lengths were observed following administration of artificially extended day length (124.8 ± 15.11 days) in the final months of pregnancy to a group of Thoroughbred mares compared to controls (P < 0.05; 339.7 ± 9.56 days vs 350.6 ± 9.13). Study 2 revealed that pre-partum exposure to artificially extended day length (104.6 ± 9.89 days) increased foal birth weight compared to controls (47.13 ± 2.93 kg vs 43.51 ± 6.14 kg; P < 0.05) in mares bred early in the year. In Study 3, artificially extended day length (87.53 ± 19.6 days) administered to pre-partum mares affected the coat condition of foals at birth with respect to hair weight (P < 0.0001) and hair length (P < 0.0001) compared to controls (0.34 ± 0.20 µg vs 0.59 ± 0.12 µg and 1.93 ± 0.56 cm vs 2.56 ± 0.32 cm, respectively). Collectively, these studies serve to highlight the influential role of the circa-annual changes in photoperiod length on the pre-partum mare for normal foetal development during the natural breeding season. It also emphasizes the potential that exists to improve breeding efficiency parameters by artificially simulating this important environmental cue in the latter stages of gestation against the backdrop of an economically driven early breeding season.

Preference for shelter and additional heat in horses exposed to Nordic winter conditions.

REASONS FOR PERFORMING STUDY: Horses may adapt to a wide range of temperatures and weather conditions. Owners often interfere with this natural thermoregulation ability by clipping and use of blankets. OBJECTIVES: To investigate the effects of different winter weather conditions on shelter seeking behaviour of horses and their preference for additional heat. STUDY DESIGN: Observational study in various environments. METHODS: Mature horses (n = 22) were given a free choice test between staying outdoors, going into a heated shelter compartment or into a nonheated shelter compartment. Horse location and behaviour was scored using instantaneous sampling every minute for 1 h. Each horse was tested once per day and weather factors were continuously recorded by a local weather station. RESULTS: The weather conditions influenced time spent outdoors, ranging from 52% (of all observations) on days with mild temperatures, wind and rain to 88% on days with <0°C and dry weather. Shivering was only observed during mild temperatures and rain/sleet. Small Warmblood horses were observed to select outdoors less (34% of all observations) than small Coldblood horses (80%). We found significant correlations between hair coat sample weight and number of observations outdoors (ρ = 0.23; P = 0.004). CONCLUSIONS: Horses selected shelters the most on days with precipitation and horses changed from a nonheated compartment to a heated compartment as weather changed from calm and dry to wet and windy. Horse breed category affected the use of shelter and body condition score and hair coat weight were associated with voluntary shelter selection.

The impact of hair coat color on longevity of Holstein cows in the tropics.

BACKGROUND: Over two decades of observations in the field in South East Asia and Hawai'i suggest that majority of the commercial dairy herds are of black hair coat. Hence a simple study to determine the accuracy of the observation was conducted with two large dairy herds in Hawaii in the mid-1990s. METHODS: A retrospective study on longevity of Holstein cattle in the tropics was conducted using DairyComp-305 lactation information coupled with phenotypic evaluation of hair coat color in two large dairy farms. Cows were classified into 3 groups: a) black (B, >90%); b) black/white (BW, 50:50) and c) white (W, >90%). Cows with other hair coat distribution were excluded from the study. In farm A, 211 out of 970 cows were identified having 4 or more lactations. In farm B, 690 out of 1,350 cows were identified with 2 or more lactations for the study. RESULTS: The regression analyses and the Wilcoxon-Log-rank test for survival probability showed that Holstein cattle with 90% black hair coat had greater longevity compared to Holstein cattle with 90% white hair coat. CONCLUSIONS: This study suggests that longevity of Holstein cattle in tropical regions was influenced by hair coat color and characteristics.

Genetic and environmental factors that affect tick infestation in Nelore x Angus crossbreed cattle / Fatores genéticos e ambientais que afetam a infestação de carrapatos em bovinos cruzados Nelore x Angus

ABSTRACT: This study evaluated the effects of seasons and latitude on tick counting and determined the best model to estimate genetic parameters for tick count and hair coat. Records of animals naturally exposed to ticks on farms in several Brazilian states and in Paraguay were used. The ANOVA was used to verify the effects of seasons and latitude on the tick count trait. Spring was the season with the highest average, followed by summer and autumn, which showed no differences between them. The winter presented the lowest average values. Latitude -11° had the highest mean value followed by latitude -18°. The Bayesian approach was used to evaluate tick count and hair coat and to identify a suitable model for estimating genetic parameters for use in genetic evaluations. The data were analyzed using an animal model with four different specifications for "fixed" purposes. The inference was based on a Markov chain Monte Carlo (MCMC). The criteria for selection of the Bayesian model indicated that the M1 model, which considered the breed composition in the contemporary group, was superior to the other models, both for tick count and hair coat. Heritability estimates for tick count and hair coat obtained using the M1 model were 0.14 and 0.22, respectively. The rank correlations between the models for tick count and hair coat were estimated and reordering was verified for tick count. The estimated genetic correlation between tick count and hair coat traits was negative (-0.12). These findings suggest that different genes regulate tick count and hair coat.

RESUMO: Os objetivos foram avaliar os efeitos das estações e latitude na contagem de carrapatos e determinar o melhor modelo para estimar parâmetros genéticos para contagem de carrapatos e pelame. Foram utilizados registros de animais expostos naturalmente a carrapatos em fazendas em vários estados brasileiros e no Paraguai. A ANOVA foi utilizada para verificar os efeitos das estações e da latitude na característica de contagem de carrapatos. A primavera foi a estação com a maior média, seguida pelo verão e outono, que não mostraram diferenças entre eles. O inverno apresentou os menores valores médios. A latitude -11° teve o maior valor médio seguido pela latitude -18°. A abordagem bayesiana foi usada para avaliar a contagem de carrapatos e o pelame e identificar o modelo adequado para estimar parâmetros genéticos e para uso em avaliações genéticas. Os dados foram analisados usando um modelo animal com quatro especificações diferentes para efeitos "fixos". A inferência foi baseada em uma cadeia de Markov Monte Carlo (MCMC). Os critérios de seleção do modelo bayesiano indicaram que o modelo M1, que considerou a composição racial no grupo contemporâneo, foi superior aos demais modelos, tanto na contagem de carrapatos e para pelame. As estimativas de herdabilidade para contagem de carrapatos e pelame obtidas usando o modelo M1 foram de 0,14 e 0,22, respectivamente. As correlações de ranking entre os modelos para a contagem de carrapatos e pelame foram estimadas e a reordenação foi verificada para a contagem de carrapatos. A correlação genética estimada entre a contagem de carrapatos e pelame foi negativa (-0,12). Esses achados sugerem que genes diferentes regulam a contagem de carrapatos e pelame.

Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs.

Abstract An instrument is described which uses air aspirated via a narrow probe from an animal's hair coat to assess the relative humidity (RH) of air within the coat. This was used to investigate regional differences in coat humidity in a group of 21 Newfoundland dogs maintained in a constant environment of 40%RH. At sites over the rump, mid-lateral thigh and chest wall, the coat RH was about 50%, whilst beneath the tail and on the ventral neck the RH was about 70%. It was observed that at tail and neck sites the RH rose with increasing age of the subject. No differences were observed related to the coat colour or sex of the subjects, but coat type was relevant. The relative humidity of finer coats on exposed sites was about 7% lower than those of normal coats. The physical features affecting these findings, i.e. convection, conduction and the effect of matting, are discussed, together with the implications for microbial colonization. Résumé- Un instrument qui utilise à l'aide d'une sonde étroite l'air aspiréà partir du pleage pour mesurer l'humidité relative (HR) du pelage est décrit. Celui-ci a été employé pour déterminer les différences régionales de l'humidité relative dans un groupe de 21 Terre Neuves maintenus dans un environnement constant à 40% d'humidité relative. L'humidité relative est de 50% sur les membres, les faces internes des cuisses et le thorax, tandis que sous la queue et le cou, elle est de 70%. Il a été observéégalement qu'au niveau de la queue et du cou, l'humidité relative augmente avec l'âge. Aucune différence n'est notée en function de la couleur du pelage et le sexe des animaux. L'humidité relative des pelages plus fins des sites exposés est de 7% plus bas que celle des pelages normaux. Les facteurs physiques influant sur l'humidité relative tels que la convection, la conduction, l'effet du pansage sont discutés notamment avec leurs implications possibles dans la colonisation microbienne. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Cartographie de la peau du chien: étude de l'humidité relative du pelage des Terre Neuve). Veterinary Dermatology 1996; 7: 35-41.] Resumen Se describe un instrumento que utiliza aire aspirado del pelo de un animal a través de una sonda para evaluar la humedad relativa (HR) del aire en el pelo. Ello se utilizó para investigar las diferencias regionales en humedad del pelo en un grupo de 21 perros Terranova mantenidos en un medio ambiente constante al 40% HR. En las zonas de grupa, muslo medial-lateral y pared torácica, la HR del pelo fue del 50%, mientras que bajo la cola y en cuello ventral fue del 70%. Se observó que la HR en la cola y cuello aumentaba con la edad del individuo. No se observaron diferencias por color del pelo o sexo, pero el tipo de pelo sí tenía importancia. La HR en pelo más fino en las zonas expuestas era un 7% menor que el de pelo normal. Se discuten los factores fisicos que afectan estas zonas, p.ej. convección, conducción y el efecto del enmarañamiento, junto con las implicaciones que ello tiene en la colonización bacteriana. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Mapeo de la piel canina: estudio de la humedad relativa del pelo en perros Terranova). Veterinary Dermatology 1996; 7: 35-41.] Zusammenfassung- Es wird ein Gerät beschrieben, welches Luft verwendet, die mit einer schmalen Sonde aus dem Haarkleid des Tieres gewonnen wurde, um die relative Feuchtigkeit (RH) der Luft innerhalb des Fells auszuwerten. Dies wurde benützt, um regipnale Unterschiede in der Fellfeuchtigkeit bei einer Gruppe von 21 Neufundländern, die unter konstanten Umgebungsbedingungen von 40% RH gehalten wurden. An Stellen über dem Rumpf, mittel-lateralen Schenkel und der Brustwand betrug die Fell-RH um 50%, während sie unter dem Schwanz und am ventralen Hals 70% aufwies. Es wurde beobachtet, daß an der Schwanz- und Halsregion die RH mit zunehmendem Alter des Tieres zunahm. Es konnten keine Unterschiede bezüglich Fellfarbe oder Geschlecht der Tiere festgestellt werden, der Felltyp war jedoch relevant. Die relative Feuchtigkeit über feinerem Fell an exponierten Regionen war 7% niedriger als die über normalem Fell. Die physikalischen Vorgänge, die diese Befunde beeinflussen, z.B. Konvektion, Konduktion und die Wirkung des 'Matting' werden diskutiert zusammen mit den Beziehungen zur mikrobiellen Besiedelung. [Chesney, C. J. Mapping the canine skin: a study of coat relative humidity in Newfoundland dogs (Landkarte der Hundehaut: Studie über die Feuchtigkeit im zusammenhang mit dem Haarkleid beim Neufundländer). Veterinary Dermatology 1996; 7: 35-41.].

Productive performance and carcass traits of Nellore x Aberdeen Angus and Nellore x Red Angus heifers under tropical conditions / Rendimiento productivo y características de la canal de Novillas Nelore x Aberdeen Angus y Nelore x Angus Colorado en condiciones tropicales / Desempenho produtivo e características de carcaça de Novilhas Nelore x Aberdeen Angus e Nelore x Red Angus sob condições tropicais

Background: Angus breed strains (Black and Red) perform differently under tropical conditions. Objective: to evaluate differences among F1 Nellore x Aberdeen Angus and F1 Nellore x Red Angus regarding productive performance and carcass traits under tropical conditions. Methods: forty-one heifers were used to assess the effect of both genetic groups on productive performance and carcass traits. The performance parameters evaluated were final live body weight and average daily gain. The carcass traits were: 1) hot and cold carcass weight and cold carcass dressing percentage, 2) carcass conformation and fatting (both ranging from 1 to 5), 3) back fat thickness, 4) rib eye area, 5) cutability, and 6) total usable meat, and commercial cut yield. Animals were divided in two groups and fed Megathyrsus maximum grass in three pens for 28 days. After this period, animals were relocated in a feedlot system for 84 days, and weighed at the beginning and at the end. All data were subjected to analysis of variance with initial live weight as a covariate. Results: differences were found between groups for productive performance and carcass traits such as back fat, and rib eye area. However, no difference was observed for conformation, fatting, ease of cutability, total usable meat, and Brazilian commercial cuts. Conclusion: F1 Nellore x Aberdeen Angus heifers had increased growth performance and carcass traits under tropical conditions.

Antecedentes: las variedades de la raza Angus (Negro o Rojo) pueden exhibir un rendimiento diferente en condiciones tropicales. Objetivo: el objetivo fue evaluar las diferencias entre los grupos genéticos de bovinos Nelore x Angus F1 y F1 Nelore x Angus Colorado en cuanto al rendimiento de la canal y las características productivas en condiciones tropicales. Métodos: se utilizaron 41 novillas para evaluar los grupos genéticos con respecto al crecimiento y características de la canal. Como parámetros de rendimiento productivo se evaluó el peso vivo final y la ganancia diaria, y para características de la canal: 1) peso en canal caliente, fría y rendimiento, 2) conformación de la canal, 3) el espesor de grasa, 4) área del ojo del lomo, 5) cortabilidad y 6) carne total utilizable y cortes comerciales brasileños. Los animales fueron divididos en dos grupos y alimentados con pasto Megathyrsus maximum bajo pastoreo rotacional en tres corrales durante 28 días. Luego fueron trasladados 84 dias a un sistema de confinamiento, siendo pesados al inicio y al final del tratamiento. Todos los datos fueron sometidos a análisis de varianza con el peso vivo inicial como covariable. Resultados: hubo diferencias en el rendimiento productivo y características de la canal, en espesor de grasa dorsal y área del ojo del lomo. Sin embargo, no hubo diferencia en la conformación, el acabado, cortabilidad, la carne utilizable total y de los cortes brasileños. Conclusión: novillas F1 Nellore x Aberdeen Angus presentaron mayor rendimiento y características de la canal de crecimiento en condiciones tropicales.

Antecedentes: animais da raça Angus podem apresentar desempenho diferente de acordó com a linha (Red Angus ou Black Angus). Objetivo: objetivou avaliar os grupos genéticos bovinos F1 Nelore x Angus Aberdeen e Nelore x Red Angus quanto ao desempenho produtivo e características de carcaça em condições tropicais. Métodos: foram utilizadas quarenta e uma novilhas para avaliar o grupo genético em relação ao desempenho de crescimento e características de carcaça. Como parâmetros de desempenho produtivo foram avaliados o peso vivo final e ganho diário e para características de carcaça: 1) peso de carcaça quente, fria e rendimento, 2) conformação da carcaça e de acabamento, 3) espessura de gordura, 4) área de olho de lombo, 5) retalhabilidade e 6) porção comestível total e rendimento de cortes comerciais brasileiros. Os animais foram divididos em dois grupos e alimentados em pastagem de Megathyrsus maximum sob pastejo rotacionado em três piquetes por 28 dias e posteriomente confinados por 84 dias, onde foram pesados no início e no final do tratamento. Todos os dados foram submetidos à análise de variância com o peso vivo inicial como covariável. Resultados: houve diferenças em desempenho produtivo e características de carcaça, a espessura de gordura subcutânea e a área de olho de lombo. No entanto, não houve diferença para conformação, acabamento, cutabilidade e rendimento dos cortes brasileiros. Conclusão: novilhas Nelore x Angus Aberdeen apresentaram melhores caracterististicas de carcaça e desempenho.

Características morfológicas do pelame de vacas holandesas puras por cruza na região semiárida de Minas Gerais / Hair coat characteristics of graded Holstein cows in semiarid region of Minas Gerais State, Brazil

O objetivo do trabalho foi avaliar as características morfológicas como densidade numérica e espessura do pelame e comprimento dos pelos de vacas Holandesas predominantemente negras, puras por cruza em lactação na região de Montes Claros no norte de Minas Gerais. O estudo foi conduzido em duas fases, A: julho/agosto e B: outubro/novembro de 2010, utilizando 12 fêmeas Holandesas em lactação, puras por cruza de pelame predominante negro. Foram medidas as características de densidade numérica (nº pelos/cm²), espessura (mm), comprimento (mm) e a temperatura da superfície do pelame (TPE). Os resultados mostraram que o pelame foi menos denso, com pelos mais curtos na fase B, no entanto a espessura não variou entre as duas fases. No período em que ocorreu maior densidade numérica houve menor TPE. As características do pelame das vacas Holandesas puras por cruza observadas indicam uma boa adequação às condições ambientais da região em estudo.

The aim of this work was to evaluate the morphological characteristics such as number density, coat thickness and length of predominantly black lactating graded Holstein cows, in the region of Montes Claros in the north of Minas Gerais. The study was conducted in two phases, A: July/August and B: October/November 2010, using 12 lactating female Holstein crossbred dairy cows with predominant black coat. We measured the characteristics of numerical density (number of hair/cm²), thickness (mm) length (mm) and coat surface temperature (CST). Three samples of hair of each animal were taken at each stage through adjusted pliers. The results showed that the coat was less dense, with shorter hair in phase B, and the thickness did not change in the two phases. In the period when the coat was denser, that is, phase A, there was lower CTS. The observed coat characteristics of graded Holstein cows indicate good adaptation to environmental conditions in the region.