Inhibition patterns and seasonal availability of nematodes for beef cattle grazing on argentina''s western pampas

The seasonal population trends of cattle nematodes in tracer calves are described from 1981 to 1987. Successive worm-free calves were grazed with growing beef cattle for 20–30 days at 6 week intervals and then slaughtered for nematode counts 2 weeks after their removal from pasture. Ostertagia, Cooperia, Trichostrongylus and Haemonchus were the main genera recovered. O.ostertagi was the most often found and acquisition of inhibition-prone larvae began in late winter and reached a peak in spring, while maximum larval availability was in autumn. The seasonal inhibition and larval availability pattern for T. axei was similar to that of Ostertagia. Cooperia showed greatest inhibition during winter with maximum larval availability in autumn and spring. Haemonchus was more prevalent during summer to early autumn and no inhibition was observed. It was concluded that infective larval availability for tracer calves was highest during autumn, and most reduced in summer. All predominant species were able to survive over summer on pasture,     

Investigation of methanogen population structure in biogas reactor by molecular characterization of methyl-coenzyme M reductase A (mcrA) genes

The methanogen community in biogas reactor running on cattle dung was investigated in two different seasons; summer (April, 36 °C) and winter (December, 24 °C), in the year 2004 by a culture-independent approach. Community structure was determined by phylogenetic analyses of 343 and 278 mcrA clones belonging to summer and winter month libraries, respectively. In summer month’s library, 41.7% clones were affiliated to Methanomicrobiales, 30% to Methanosarcinales, 19% to Methanobacteriales, 5% to Methanococcales and a total of 4.3% clones belonged to unclassified euryarchaeotal lineages. In winter month’s library, Methanomicrobiales encompassed 98.6% clones, and Methanobacteriales included 1.4% of total clone diversity. Biogas plant performance data collected during the winter month indicated significant reduction in daily biogas produced as compared to summer month because of lowering in ambient temperature and associated shift in microbial community. Results from this molecular study showed the existence of highly diverse and complex methanogens communities present in biogas plant.     

The role of salinity tolerance and competition in the distribution of an endangered desert salt marsh endemic

Rare plants are often associated with distinctive soil types, and understanding why endemic species occur in unique environments is fundamental for their management. At Ash Meadows National Wildlife Refuge in southern Nevada, USA, we evaluated whether the limited distribution of endangered Amargosa niterwort (Nitrophila mohavensis) is explained by this species’ tolerance of saline soils on salt-encrusted mud flats compared with the broadly distributed desert saltgrass (Distichlis spicata var. stricta). We simultaneously explored whether niterwort distribution is restricted from expanding due to interspecific competition with saltgrass. Surface soils collected throughout niterwort’s range were unexpectedly less saline with lower extractable Na, seasonal electroconductivity, and Na absorption ratio, and higher soil moisture than in adjacent saltgrass or mixed shrub habitats. Comparison of niterwort and saltgrass growth along an experimental salinity gradient in a greenhouse demonstrated lower growth of niterwort at all but the highest NaCl concentrations. Although growth of niterwort ramets was similar when transplanted into both habitats at the refuge below Crystal Reservoir, niterwort reproductive effort was considerably higher in saltgrass compared to its own habitat, implying reallocation of resources to sexual reproduction to maximize fitness when the probability of ramet mortality increases with greater salinity stress. Saltgrass was not a demonstrated direct competitor of niterwort; however, this species is known to increase soil salinity by exuding salt ions and through litterfall. Niterwort conservation will benefit from protecting hydrological processes that reduce salinity stress and preventing saltgrass colonization into niterwort habitat.     

陕甘宁地区降水同位素云下二次蒸发效应

大气降水过程中,雨滴由云层底部降落至地面经过不饱和空气时发生的蒸发现象,即为云下二次蒸发,这会使得降水同位素组成发生改变。利用氢氧稳定同位素方法研究云下二次蒸发效应的时空变化及其成因,对探讨区域水循环过程具有重要意义。本研究基于陕甘宁地区2018年3月—2019年2月187个气象站逐小时气象数据,采用改进后的Stewart模型,分析了该区域蒸发剩余比(f)与降水过量氘变化量(Δd)的时空变化,并探讨了f以及气象要素与Δd的关系。结果表明: 从小时尺度来看,该区域各省f与Δd最小值均出现在白天,最大值出现在夜晚,即白天云下二次蒸发效应更明显。从月尺度来看,各省f、Δd月变化趋势较为一致,最小值多出现在夏半年,最大值多出现在冬半年,即夏半年云下二次蒸发效应更显著。研究区f、Δd值在季节尺度上的空间变化一致:春季,东、西部地区较大,中部较小;夏季,西北部地区偏小,其他地区偏大;秋季,由南向北减小;冬季,中部、南部较小,西部及东北部较大,研究区不同季节云下二次蒸发效应的空间差异显著。陕甘宁三省(区)f与Δd的线性关系的斜率均小于1‰·%^-1,这可能与该地区干旱半干旱气候具有较大关系。当气温较高,相对湿度、水汽压、降水量和雨滴直径较小时,Δd值较小,云下二次蒸发效应较明显。     

基于占域模型的中国珲春地区人虎冲突特征分析

人虎冲突是全球野生虎(Pantheratigris)保护和种群恢复工作迫切需要解决的问题,而人虎冲突的分布特征是开展冲突管理的重要科学依据.珲春地区是东北虎(P.t.altaica)从俄罗斯向中国扩散的重要廊道,随着东北虎种群数量的逐步增加,该地区的人虎冲突特征亟需开展研究.本文以2016-2020年珲春地区的人虎冲突...     

Vaccination against Babesia bovis: T cells from protected and unprotected animals show different cytokine profiles

Vaccination of cattle against the haemoprotozoun parasite, Babesia bovis, with the recombinant antigen 11C5 resulted in 9 of 15 cattle being protected against challenge infection. The cellular immune responses of protected and unprotected cattle were compared in order to identify differences in response. No differences were observed in the pattern of change in various blood leukocyte populations throughout challenge infection. FACScan analysis revealed an increase in the proportion of cells bearing the CD2 marker in both protected and unprotected cattle over the course of infection. There were no observable differences in the frequency of various cell-surface markers between the unprotected and protected cattle. During the period of patent parasitaemia, in vitro cultures of peripheral blood mononuclear cells (PBMC) from protected cattle produced significantly more TNF- (P < 0.05) than cultures from unprotected cattle. TNF- concentrations remained at pre-challenge levels until day 10, when levels in the unvaccinated control and vaccinated/unprotected animals dropped. By peak parasitaemia, TNF- production in vitro was siguificantly greater (P < 0.05) in cultures of PBMCs from protected cattle. Interferon production showed an initial peak at day 5 in all cattle, followed by a decrease and a second peak at days 10–13 in protected cattle only, which coincided with resolution of the infection.     

大兴安岭兴安落叶松径向生长对气候响应的时空变化

根据兴安落叶松在大兴安岭山脉的分布特征,沿纬度设置了9个采样点,分析了兴安落叶松径向生长对气候因子响应的空间差异和时间动态。结果表明:总体上所有采样点的兴安落叶松径向生长与夏季(6—8月)标准化降水蒸散指数(SPEI)及降水量、2月SPEI及降水量呈正相关,与3月温度呈负相关。在空间上,南部年均温较高区域的兴安落叶松径向生长与2月SPEI呈显著正相关,在北部年均温较低的区域与3月温度呈显著负相关。在时间上,兴安落叶松生长-气候关系不稳定。随着温度升高,在年均温较高区域,夏季SPEI和降水量对树木生长的正效应以及夏季温度的负响应显著增强;在年均温较低区域,树木生长与3月温度负响应增强更明显。这表明气候变化改变了树木生长-气候关系,而且存在明显空间差异。在未来气候暖干化的背景下,大兴安岭兴安落叶松径向生长会受到抑制,在年均温较高且降水量较少的南部地区会因夏季水分亏缺和冬季干旱而衰退,温度较低的北部地区则可能因冬季干旱和冬季变暖而使生长受到抑制。     

Molecular epidemiology of Cryptosporidium in humans and cattle in The Netherlands

The protozoan parasite Cryptosporidium is found world-wide and can cause disease in both humans and animals. To study the zoonotic potential of Cryptosporidium in The Netherlands we isolated this parasite from the faeces of infected humans and cattle and genotyped those isolates for several different markers. The overall genotyping results showed: for humans isolates, 70% Cryptosporidium hominis, 19% Cryptosporidium parvum, 10% a combination of C. hominis and C. parvum, and 1% Cryptosporidium felis; and for cattle isolates 100% C. parvum. Analysis of the genetic variants detected for the HSP70, ML1 and GP60 markers showed: for human isolates, one C. hominis and two C. parvum variants (C. parvum and C. parvum NL) for HSP70, one C. hominis and five C. parvum variants (C1, C2, C3, and C2 NL1 and C2 NL2) for ML1, four C. hominis (mainly IbA10G2) and four C. parvum variants (mainly IIaA15G2R1) for GP60; and the cattle isolates only C. parvum (not C. parvum NL1) for HSP70, C1 and C2 for ML1, and 17 different IIa sub-types (mainly IIaA15G2R1) for GP60. Molecular epidemiological analysis of the human data showed a C. hominis peak in autumn. The majority (80%) of the human cases were children aged between 0 and 9 years and >70% of these were caused by C. hominis. Patients >25 years of age were infected mainly with C. parvum. We conclude that C. hominis IbA10G2 is found at high frequencies in autumn in humans and not in cattle. The high prevalence of C. parvum IIaA15G2R1 in both humans and cattle indicates that cattle may be a reservoir for this sub-type in The Netherlands.     

Varying foraging strategies of Labridae in seagrass habitats: Herbivory in temperate seagrass meadows?

The diets of five species of Labridae in south-western Australia were examined to determine whether: (1) grazing of seagrass and epiphytic algae is a prominent feature of the food web within the deeper seagrass meadows of this temperate region; (2) levels of grazing differ among different seagrass systems; and diets differ among these closely-related species. Fish were collected seasonally from three seagrass habitats mainly comprising either Posidonia sinuosa, Posidonia coriacea or Amphibolis griffithii between the summer of 1996/97 and spring of 1997. Consumption of considerable amounts of algae and seagrass by Odax acroptilus and seagrass by Haletta semifasciata indicates that macrophyte grazing by fish is a component of the trophic dynamics of south-western Australian seagrass meadows. O. acroptilus and H. semifasciata were both omnivorous, feeding on a range of epifauna, infauna and flora, whereas Siphonognathus radiatus, Neoodax balteatus and Notolabrus parilus were carnivorous, feeding predominantly on motile epifauna, such as molluscs and crustaceans. The level of macrophyte grazing is likely to be underestimated in temperate offshore meadows of P. sinuosa and A. griffithii where omnivorous labrids, monacanthids and terapontids are abundant. Stable isotope data for O. acroptilus from the study region suggest that animal prey is more important to tissue maintenance than macrophyte material. Macrophytes may be grazed to acquire attached animal prey or for fulfilling energy requirements. Based on the distribution of prey, it appears that species in A. griffithii meadows forage within and below the seagrass canopy, whilst species in P. sinuosa meadows are likely to forage towards the basal area of this seagrass.     

Use of deciduous woody species as a diet supplement for goats grazing Mediterranean shrublands during the dry season

Nutritional stress during the dry summer period is considered as a primary factor limiting goat production in the Mediterranean region. This study was conducted to determine if the browse of deciduous woody fodder plants is useful as a supplement for goats grazing kermes oak shrublands during July and September. Browses used were of Amorpha fruticosa L., Carpinus orientalis Mill., Colutea arborescens L., Fraxinus ornus L., Ostrya carpinifolia Scop. and Robinia pseudoacacia L.. Treatments included: (1)–(6) kermes oak (Quercus coccifera L.) shrubland plus fresh branches (2 kg/animal/day) of one of the above fodder plants as browse supplement, (7) kermes oak shrubland plus 0.25 (July) or 0.5 (September) kg alfalfa pellets/animal/day and (8) grazing in kermes oak shrubland as a control. Fodder plants produced high amounts of grazable material during summer whose quality ranged from medium (Carpinus, Fraxinus, Ostrya) to high (Amorpha, Colutea and Robinia). Goats ingested higher (p ≤ 0.05) browse of Fraxinus (268 g DM) and Ostrya (285 g DM) than the remaining browses (22–177 g DM) and alfalfa pellets (170 g DM) during July, but of Robinia and alfalfa (469 and 434 g DM, respectively) in September. During September, intake of all supplement feeds increased compared to July except for Ostrya, which remained constant. Goats supplemented by alfalfa pellets and browse supplements gained weight in both these periods in contrast to the animals grazing only kermes oak shrubland, except for Amorpha and Colutea in July. It is concluded that during summer, when the forage quality of kermes oak shrubland declines, browse supplement with certain deciduous woody fodder plants allows weight gains similar to those of alfalfa pellets; thereby, improving grazing animal performance.     

闽江口-平潭海域有机解磷菌多样性及群落特征

有机磷的微生物矿化是海洋磷循环的重要环节,开展有机解磷菌研究有助于揭示富营养化海域有机磷矿化的微生物驱动机制。以phoX为标志基因,采用Illumina高通量测序技术分析了闽江口-平潭海域2019年4月(春季)及7月(夏季)有机解磷菌的多样性及群落特征。结果表明: 表层海水样品中有机解磷菌的Shannon指数介于3.21～7.91,各站位多样性春季均大于夏季;沉积物样品中有机解磷菌的Shannon指数介于2.04～8.70,各站位多样性夏季大于春季。春季各站位表层海水有机解磷菌的Shannon指数均高于沉积物,而夏季则相反。表层海水中检测到9个门类的有机解磷菌,主要为变形菌门和蓝细菌门;沉积物中则检测到12个门类,主要为变形菌门和拟杆菌门。在属水平上,有机解磷菌的群落组成呈现时空变异特征。表层海水样品中,春季以雷辛格氏菌属、褐杆菌属、深海球菌属和假单胞菌属等属为主,夏季则以聚球藻属、Halioglobus属、玫瑰变色菌属、褐杆菌属、亚硫杆菌属和生丝单胞菌属等属为主。在沉积物样品中,春季主要菌属包括雷辛格氏菌属、褐杆菌属、弧菌属和亚硫杆菌属;夏季主要菌属包括固氮螺丝菌属、氨基杆菌属、Sulfurifustis属、伯克氏菌属和Thiohalobacter属。此外,在表层海水和沉积物样品中均检测到大量未分类的有机解磷菌。冗余分析显示,溶解氧、水温、pH、可溶性无机氮、亚硝态氮、硝态氮等对闽江口-平潭海域表层海水有机解磷菌群落分布影响较大。表层海水和沉积物中存在的丰富有机解磷菌可能在该海域的磷循环中发挥重要作用。     

Major surface protein 1a effects tick infection and transmission of Anaplasma marginale.

Anaplasma marginale, an ehrlichial pathogen of cattle and wild ruminants, is transmitted biologically by ticks. A developmental cycle of A. marginale occurs in a tick that begins in gut cells followed by infection of salivary glands, which are the site of transmission to cattle. Geographic isolates of A. marginale vary in their ability to be transmitted by ticks. In these experiments we studied transmission of two recent field isolates of A. marginale, an Oklahoma isolate from Wetumka, OK, and a Florida isolate from Okeechobee, FL, by two populations of Dermacentor variabilis males obtained from the same regions. The Florida and Oklahoma tick populations transmitted the Oklahoma isolate, while both tick populations failed to transmit the Florida isolate. Gut and salivary gland infections of A. marginale, as determined by quantitative PCR and microscopy, were detected in ticks exposed to the Oklahoma isolate, while these tissues were not infected in ticks exposed to the Florida isolate. An adhesion-recovery assay was used to study adhesion of the A. marginale major surface protein (MSP) 1a to gut cells from both tick populations and cultured tick cells. We demonstrated that recombinant Escherichia coli expressing Oklahoma MSP1a adhered to cultured and native D. variabilis gut cells, while recombinant E. coli expressing the Florida MSP1a were not adherent to either tick cell population. The MSP1a of the Florida isolate of A. marginale, therefore, was unable to mediate attachment to tick gut cells, thus inhibiting salivary gland infection and transmission to cattle. This is the first report of MSP1a being responsible for effecting infection and transmission of A. marginale by Dermacentor spp. ticks. The mechanism of tick infection and transmission of A. marginale is important in formulating control strategies and development of improved vaccines for anaplasmosis.     

Observations on the cross-immunity between Theileria lawrencei (Serengeti) and Theileria parva (Muguga) in cattle

Observations on the cross-immunity between Theileria lawrencei (Serengeti) and Theileria parva (Muguga) in cattle. Internationaljournal for Parasitology 3: 723–728. Cattle immunized against Theileria parva (Muguga) showed little resistance to Theileria lawrencei (Serengeti) stabilate challenge, while cattle immune to T. lawrencei (Serengeti) were fully resistant to challenge with T. parva (Muguga) stabilate. Cattle inoculated with cultured lymphoid cells infected with T. lawrencei (Serengeti) macroschizonts survived a subsequent T. lawrencei (Serengeti) stabilate challenge.     

淇澳岛两种红树林区大型底栖动物群落比较

对珠海淇澳岛天然秋茄(Kandelia candel)与人工恢复无瓣海桑(Sonneratia apetala)两种红树林林地间大型底栖动物群落结构进行了比较研究.结果显示,天然秋茄林与人工无瓣海桑林林地大型底栖动物种类组成及数量分布都存在差异,秋茄林大型底栖动物平均生物量、栖息密度分别为668.64g·m^-2和8370个·m^-2,无瓣海桑林分别为511.64g·m^-2和4748个·m^-2.两个红树林剖面不同潮位带大型底栖动物结构存在差异,秋茄林生物量和栖息密度的最高值都在中潮带,主要是由节肢动物和软体动物所主导:无瓣海桑林栖息密度的最高值也是在中潮带,生物量变化比较不规则.两个红树林剖面大型底栖动物群落特征的季节变化较明显,生物量都是秋季处于最高水平:栖息密度都是冬季处于最高水平,秋季最低:生物多样性都是夏季处于最低,但最高值秋茄林剖面是在春季,而无瓣海桑林剖面则是秋季.研究结果表明,林地底质和盐度等生境条件以及红树林群落的高度、郁闭度和林下通风透光等生态特征的差异是造成红树林底栖动物群落差异的重要原因.     

A panel of microsatellite and minisatellite markers for the characterisation of field isolates of Theileria parva

Mini- and microsatellite sequences show high levels of variation and therefore provide excellent tools for both the genotyping and population genetic analysis of parasites. Herein we describe the identification of a panel of 11 polymorphic microsatellites and 49 polymorphic minisatellites of the protozoan haemoparasite Theileria parva. The PCR products were run on high resolution Spreadex gels on which the alleles were identified and sized. The sequences of the mini- and microsatellites were distributed across the four chromosomes with 16 on chromosome 1, 12 on chromosome 2, 14 on chromosome 3 and 18 on chromosome 4. The primers from the 60 sequences were tested against all the Theileria species that co-infect cattle in East and Southern Africa and were found to be specific for T. parva. In order to demonstrate the utility of these markers, we characterised eight tissue culture isolates of T. parva isolated from cattle in widely separated regions of Eastern and Southern Africa (one from Zambia, one from Uganda, two from Zimbabwe, four from Kenya) and one Kenyan tissue culture isolate from Cape buffalo (Syncerus caffer). The numbers of alleles per locus range from three to eight indicating a high level of diversity between these geographically distinct isolates. We also analysed five isolates from cattle on a single farm at Kakuzi in the central highlands of Kenya and identified a range of one to four alleles per locus. Four of the Kakuzi isolates represented distinct multilocus genotypes while two exhibited identical multilocus genotypes. This indicates a high level of diversity in a single population of T. parva. Cluster analysis of multilocus genotypes from the 14 isolates (using a neighbour joining algorithm) revealed that genetic similarity between isolates was not obviously related to their geographical origin.     

Carry-over effect of summer thermal stress on characteristics of the preovulatory follicle of lactating cows

Low fertility of cattle during the cool autumn is mostly associated with exposure to thermal stress in the previous summer. This study examined carry-over effects of summer heat stress and induction of enhanced follicular turnover, on the characteristics of preovulatory follicles during autumn. Holstein cows were treated with PGF₂ and GnRH to induce six successive 9-day follicular waves during autumn. Intact cows served as controls. Follicular fluid concentrations of androstenedione were higher in treated cows, but those of IGF-I and progesterone did not differ between groups. The concentration of estradiol at the end of the treatment was higher, and the content per follicle increased with time and was numerically higher in treated cows. The volume of follicular fluid increased during the autumn and was greater in treated cows. A delayed effect of heat stress on preovulatory follicles was noted, and induction of follicular waves by GnRH was able to improve follicular characteristics in autumn.     

太行山华北豹袭击家畜的时空特点与管理建议: 以山西省和顺县为例

人兽冲突是全球野生动物保护面临的共同挑战。袭击家畜是大型食肉动物引发人兽冲突的主要原因之一, 如果管理不当还会导致针对大型食肉动物的报复性猎杀等严重威胁。冲突的缓解需要深入了解冲突发生的规律与原因, 评估当地社区与居民的态度与看法, 以采取因地制宜的管理措施。太行山是华北豹(Panthera pardus japonensis)的核心分布区, 华北豹袭击家牛的问题是该区域野生华北豹保护中面临的一大挑战。本研究以山西省和顺县为研究区域, 在多方联合发起的“和顺县华北豹袭击家牛肇事补偿项目”实施过程中, 系统收集了2015-2019年期间华北豹袭击家畜事件的记录, 结合同期的红外相机监测数据, 探究了袭击事件的时空分布格局, 并从生境和猎物的角度分析了背后的原因。本文还评估了豹肇事造成的经济损失, 以及受损农户对华北豹的态度和对补偿的满意度。2015-2019年, 项目区域内共记录到华北豹袭击家牛事件195起, 向116户受损农户提供补偿资金共27.05万元。分析结果显示, 华北豹袭击家牛事件在夏季最多, 时间上与家牛上山散放的季节重叠; 袭击风险随狍(Capreolus pygargus)相对多度的上升而下降, 随家牛相对多度和距村庄距离的增加而上升, 但保护区内外和华北豹相对多度对袭击风险的影响不显著。对107名受损农户的访谈结果显示, 华北豹袭击家牛事件虽然对当地畜牧业所造成的整体损失较小, 但对受损农户而言其家庭收入损失严重, 因此导致受损农户对华北豹持负面态度, 且认为现有的补偿金额偏低。基于本研究的结果, 我们提出如下管理建议以期缓解未来该地区华北豹带来的人兽冲突: (1)加强放牧管理、改进管理方式, 特别是限制牛群离开村庄的距离, 以及在家牛散放期间将牛群每晚赶回牛圈以降低家畜被袭击的风险; (2)开展禁牧试点, 严格划分允许放牧与禁止放牧的区域; (3)继续开展华北豹袭击家牛的定损与补偿工作, 降低当地农户的经济损失, 同时开展社区走访、自然教育, 提升当地居民对华北豹的容忍度; (4)加强野生动物种群的监测与保护, 促进人与野生动物的和谐共存。     

Diets of hooded seals (Cystophora cristata) in coastal waters and drift ice waters along the east coast of Greenland

To provide data on the diets of hooded seals (Cystophora cristata) in the Greenland Sea, seals were collected for scientific purposes on expeditions conducted in the pack ice belt east of Greenland in September/October 1999, 2002 and 2003 (autumn), July/August in 2000 (summer), and February/March in 2001 and 2002 (winter). The results from analyses of stomach and intestinal contents from captured seals revealed that their diet was comprised of relatively few prey taxa. The squid Gonatus fabricii and polar cod (Boreogadus saida) were particularly important, whereas capelin (Mallotus villosus) and sand eels (Ammodytes spp.) occasionally contributed more. These four prey items constituted 60-97% of the diet biomass. Gonatus fabricii was the most important food item in autumn and winter, whereas polar cod dominated the summer diet, with important contributions from G. fabricii and sand eels. The latter was only observed on the hooded seal menu during the summer period, whereas polar cod, which was an important component during the autumn survey, was almost absent from the winter samples. During the latter survey, capelin also contributed to the hooded seal diet. Samples obtained from hooded seals in more coastal waters indicated a more varied diet based on fish such as polar cod, redfish (Sebastes sp.) and Greenland halibut (Reinhardtius hippoglossoides).     

Expression of HSP70 genes in skin of zebu (Tharparkar) and crossbred (Karan Fries) cattle during different seasons under tropical climatic conditions

Skin is most important environmental interface providing a protective envelope to animals. It's always under the influence of both internal and external stressors. Heat shock proteins (HSP) are highly conserved stress proteins which play crucial roles in environmental stress tolerance and thermal adaptation. Present study was planned to observe the relative mRNA expression of inducible (HSP70.1 and HSP70.2) and constitutive (HSP70.8) HSP in skin of zebu (Tharparkar) and crossbred (Karan Fries) cattle during different seasons. Skin biopsies were collected from rump region of each animal, aseptically during winter, spring and summer season. Quantitative real time polymerase chain reaction was performed to examine the gene expression of constitutive (HSP70.8) and inducible (HSP70.1 and HSP70.2) HSP in skin of both the breeds during different seasons. Present study observed higher expression of both constitutive and inducible HSP genes in both the breeds during summer and winter than spring season, but magnitude of increase was higher during summer than winter. During summer season, expression pattern of HSPs in skin showed breed differences, where constitutive HSP expression was higher in Tharparkar than Karan Fries and that of inducible HSP was higher in Karan Fries than Tharparkar. Hence, present study suggested that HSP may be conveniently used as biomarkers for assessing protective response of skin against heat stress in zebu and crossbred cattle. Variation in expression between breeds is associated with their heat tolerance and thermal adaptability. In summary, skin of zebu cattle (Tharparkar) is more resistant to summer stress than crossbred (Karan Fries), providing greater protection against heat stress during summer season. Superior skin protective mechanism of zebu (Tharparkar) than crossbred (Karan-Fries) cattle against heat stress may contribute to superior adaptability of zebu cattle to tropical climatic conditions than crossbreed.