Heat stress in cattle and the effect of shade on production and behaviour: a review

At high temperatures, evaporative cooling is the principal mechanism for heat dissipation in cattle. It is influenced by humidity and wind speed and by physiological factors such as respiration rate, and density and activity of sweat glands. Following exposure to heat, cattle appear to acclimatise within 2-7 weeks. The failure of homeostasis at high temperatures may lead to reduced productivity or even death. Knowledge of characteristic behavioural signs of increasing heat stress may alert cattle handlers to impending heat distress, particularly in areas of potential climatic extremes of high temperatures and humidities. Reduction of the heat increment of feeding by dietary manipulation may partially protect cattle from forecast heat stress. Under high heat stress, Bos indicus breeds and their crosses have better heat regulatory capacities than Bos taurus breeds, due to differences in metabolic rate, food and water consumption, sweating rate, and coat characteristics and colour. Also, because Bos taurus have a higher heat loading at the skin, they must evaporate substantially more sweat than Bos indicus to maintain normal body temperatures. Welfare concerns exist about heat stress and the provision of shade for feedlot cattle. In hot weather, cattle actively seek shade, which may reduce the radiant heat load by 30% or more. Under conditions of extreme heat load, shading may maintain production and reduce deaths from heat stroke. Shading of feed and water also offers production advantages for British and European breeds of cattle.

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Influence of shade on panting score and behavioural responses of Bos taurus and Bos indicus feedlot cattle to heat load

Animal Production Science ◽

10.1071/an19013 ◽

2020 ◽

Vol 60 (2) ◽

pp. 305 ◽

Cited By ~ 1

Author(s):

A. M. Lees ◽

J. C. Lees ◽

V. Sejian ◽

M. L. Sullivan ◽

J. B. Gaughan

Keyword(s):

Treatment Group ◽

Observational Data ◽

Heat Load ◽

Bos Taurus ◽

Bos Indicus ◽

Observation Time ◽

Feedlot Cattle ◽

Night Time ◽

Treatment Groups ◽

Panting Score

Context Feedlot cattle can be negatively impacted by hot conditions, such that they have reduced performance and wellbeing. This study was conducted at the research feedlot located at The University of Queensland during a southern hemisphere summer (October to April). Aims The objective of this study was to evaluate the influence of shade on the behaviour and panting score of Bos taurus and Bos indicus feedlot cattle during summer. Methods Thirty-six steers (12 Angus, 12 Charolais and 12 Brahman) with an initial non-fasted liveweight of 318.5 ± 6.7 kg were used in a 154-day feedlot study consisting of two treatments: unshaded and shaded (3 m2/animal). Observational data were obtained for each steer at 2 h intervals between 0600 and 1800 hours daily from Day 1 to Day 154. Additional night time observational data were collected at 2-h intervals between 2000 and 0400 hours on 12 occasions. Data collected included activity (feeding, drinking, or ruminating), posture (standing or lying) and panting score. Panting scores were used to calculate a mean panting score for each breed × treatment group. Observational data were converted to a count for each breed × treatment group for each observation time point and were analysed using a binomial generalised linear model. Key results Maximum shade utilisation was the greatest at 1200 hours for Angus (85.5%), Charolais (32.7%) and Brahman (33.3%) steers. All breed × treatment groups exhibited a notable increase in mean panting score as heat load increased. Average increase in mean panting score was 0.36, where shaded Brahman exhibited the smallest increase (0.13) and unshaded Angus had the greatest increase (0.71). When heat load conditions were very hot (heat load index (HLI) ≥ 86) the mean panting score of all breed × treatment groups differed (P < 0.05). Conclusions Overall these results emphasise the importance of providing shade to feedlot cattle, irrespective of genotype. Implications These results further highlight the importance of providing shade to feedlot cattle. These results challenge the general perception that Bos indicus feedlot cattle do not require access to heat load alleviation strategies.

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Expression of candidate genes for residual feed intake in tropically adapted Bos taurus and Bos indicus bulls under thermoneutral and heat stress environmental conditions

Journal of Thermal Biology ◽

10.1016/j.jtherbio.2021.102998 ◽

2021 ◽

pp. 102998

Author(s):

Bianca Vilela Pires ◽

Nedenia Bonvino Stafuzza ◽

Luara Afonso de Freitas ◽

Maria Eugênia Zerlotti Mercadante ◽

Ester Silveira Ramos ◽

...

Keyword(s):

Heat Stress ◽

Candidate Genes ◽

Feed Intake ◽

Environmental Conditions ◽

Bos Taurus ◽

Bos Indicus ◽

Residual Feed Intake

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The thickness of cattle skin

Australian Journal of Agricultural Research ◽

10.1071/ar9550776 ◽

1955 ◽

Vol 6 (5) ◽

pp. 776 ◽

Cited By ~ 27

Author(s):

DF Dowling

Keyword(s):

Bos Taurus ◽

Bos Indicus ◽

Sweat Glands ◽

Skin Thickness ◽

Hot Environment ◽

Early Maturing ◽

The Mean ◽

Critical Characteristics ◽

Thick Skin ◽

Active Sweat Glands

The mean total skin thicknesses (mm) for the breeds sampled were: Devon 8.15, Hereford 6.7, Zebu cross 6.43, Australian Illawarra Shorthorn 6.23, Friesian 6.0, Zebu 5.77, Aberdeen Angus 5.75, Shorthorn 5.69, and Jersey 5.46. The early maturing Shorthorn (Bos taurus L.) and the Zebu (Bos indicus L.) differed significantly in the depth of the papillary and reticular layers, and in the relative thickness of these skin layers. The mean thickness for the papillary layer; was 0.98 mm in the Zebu, 1.40 mm in the Zebu cross, and 1.70 mm in the Shorthorn. Thus the larger, more active sweat glands of the Zebu are more superficial. The corresponding reticular layer averaged 4.45 mm in the Zebu, 4.5 mm in the Zebu cross, and 4.08 mm in the Shorthorn. The thickness of the papillary layer relative to the total skin thickness was 18.3, 23.7, and 29.3 per cent., for the Zebu, Zebu cross, and Shorthorn respectively. The Zebu and the Jersey have relatively thin skins. Therefore a thick skin is not essential for adaptability to a hot environment. Inherent differences in the function of the follicles and the glands of the papillary layer may be critical characteristics for heat tolerance.

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Effects of heat stress on development, quality and survival of Bos indicus and Bos taurus embryos produced in vitro

Theriogenology ◽

10.1016/j.theriogenology.2012.10.003 ◽

2013 ◽

Vol 79 (2) ◽

pp. 351-357 ◽

Cited By ~ 44

Author(s):

C.F. Silva ◽

E.S. Sartorelli ◽

A.C.S. Castilho ◽

R.A. Satrapa ◽

R.Z. Puelker ◽

...

Keyword(s):

Heat Stress ◽

Bos Taurus ◽

Bos Indicus

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Heat stress and spermatogenesis in Bos indicus and Bos taurus cattle

Journal of Applied Physiology ◽

10.1152/jappl.1966.21.6.1784 ◽

1966 ◽

Vol 21 (6) ◽

pp. 1784-1790 ◽

Cited By ~ 60

Author(s):

J. D. Skinner ◽

G. N. Louw

Keyword(s):

Heat Stress ◽

Bos Taurus ◽

Bos Indicus

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Cutaneous vascular and sudomotor responses in human skin grafts

Journal of Applied Physiology ◽

10.1152/japplphysiol.00466.2010 ◽

2010 ◽

Vol 109 (5) ◽

pp. 1524-1530 ◽

Cited By ~ 27

Author(s):

Craig G. Crandall ◽

Scott L. Davis

Keyword(s):

Heat Stress ◽

Heat Dissipation ◽

Skin Grafting ◽

Whole Body ◽

Sweat Glands ◽

Skin Grafts ◽

Local Cooling ◽

Doppler Flowmetry ◽

Graft Area ◽

The Individual

Each year millions of individuals sustain burns. Within the US 40,000–70,000 individuals are hospitalized for burn-related injuries, some of which are quite severe, requiring skin grafting. The grafting procedure disrupts neural and vascular connections between the host site and the graft, both of which are necessary for that region of skin to contribute to temperature regulation. With the use of relatively modern techniques such as laser-Doppler flowmetry and intradermal microdialysis, a wealth of information has become available regarding the consequences of skin grafting on heat dissipation and heat conservation mechanisms. The prevailing data suggest that cutaneous vasodilator capacity to an indirect heat stress (i.e., heating the individual but not the evaluated graft area) and a local heating stimulus (i.e., directly heating the graft area) is impaired in grafted skin. These impairments persist for ≥4 yr following the grafting procedures and are perhaps permanent. The capacity for grafted skin to vasodilate to an endothelial-dependent vasodilator is likewise impaired, whereas its capacity to vasodilate to an endothelial-independent vasodilator is generally preserved. Sweating responsiveness is minimal to nonexistent in grafted skin to both a whole body heat stress and local administration of the primary neurotransmitter responsible for stimulating sweat glands (i.e., acetylcholine). Likewise, there is no evidence that this absence of sweat gland responsiveness improves as the graft matures. In contrast to the heating stimuli, cutaneous vasoconstrictor responses to both indirect whole body cooling (i.e., exposing the individual to a cold stress but not at the evaluated graft area) and direct local cooling (i.e., directly cooling the graft area) are preserved in grafted skin as early as 5–9 mo postgrafting. If uninjured skin does not compensate for impaired heat dissipation of grafted skin, individuals having skin grafts encompassing significant fractions of their body surface area will be at a greater risk for a hyperthermic-related injury. Conversely, the prevailing data suggest that such individuals will not be at a greater risk of hypothermia upon exposure to cold environmental conditions.

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209 EFFECT OF HEAT STRESS ON DEVELOPMENT OF IN VITRO-FERTILIZED AND PARTHENOGENETIC BOVINE EMBRYOS

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab209 ◽

2011 ◽

Vol 23 (1) ◽

pp. 203

Author(s):

F. Paludo ◽

M. M. Pereira ◽

C. C. R. Quintao ◽

L. T. Iguma ◽

M. M. Gioso ◽

...

Keyword(s):

Heat Stress ◽

Bos Taurus ◽

Apoptotic Cell ◽

Chemical Activation ◽

Bos Indicus ◽

Bovine Embryos ◽

Cell Numbers ◽

Bovine Reproduction ◽

Blastocyst Rate

Heat stress has been a challenge for bovine reproduction in tropical and subtropical environments. Although the role of the oocyte in thermotolerance has been studied, little attention has been paid to the contributions of sperm to embryo resistance to heat shock. The current study aimed to evaluate the development of fertilized and nonfertilized (parthenogenetic) bovine embryos undergoing heat stress during the pre-implantation stage. Cumulus–oocyte complexes obtained from ovaries collected from Bos indicus × Bos taurus crossbred cows at slaughter were in vitro matured with TCM-199 supplemented with 20 μg mL–1 of FSH, under 5% CO2 at 38.5°C for 24 h. Afterward, oocytes were randomly allocated into 2 groups: 1) IVF and 2) PART (chemical activation for parthenogenesis induction). In vitro-fertilized oocytes were cultured with 2.0 × 106 Holstein sperm mL–1 in Fert-TALP medium supplemented with heparin, for 20 h. For chemical activation, oocytes were activated with calcium ionomycin for 4 min, followed by 6-DMAP for 4 h, both in CR2aa medium supplemented with 0.1% BSA. Presumptive IVF (n = 1 262) or PART (n = 1 206) zygotes were denuded by vortexing and cultured in CR2aa medium with 2.5% of FCS under 5% CO2, 5% O2, and 90% N2 at 38.5°C. At 44 h post-insemination or chemical activation, embryos were exposed to 38.5 or 41°C for 12 h in an atmosphere of 5% CO2, 5% O2, and 90% N2. After that, embryos were cultured at 38.5°C under 5% CO2, 5% O2, and 90% N2 until Day 8 post-insemination. Blastocyst rates were evaluated at Day 7 and Day 8 post-insemination and were calculated based on the total number of presumptive zygotes. Blastocysts at 192 h post-insemination or activation were fixed and permeabilized for TUNEL assay (DeadEndTM Florimetric TUNEL System, Promega, Madison, WI) according to the manufacturer’s instructions. The effect of heat stress was compared within groups (IVF or PART) and the data were analysed by ANOVA. As expected, heat stress reduced the blastocyst rate of IVF embryos at Day 7 (24.3 ± 2.0% and 17.4 ± 2.2% for nonstressed and stressed IVF embryos; P < 0.05) and at Day 8 (32.4 ± 1.9% and 23.0 ± 2.1% for nonstressed and stressed IVF embryos; P < 0.01). However, the effect of heat stress on blastocyst rate of PART embryos was observed only at Day 8 post-insemination (30.0 ± 1.7% and 22.6 ± 2.0% for nonstressed and stressed PART embryos; P < 0.05), with no difference in blastocyst rate at Day 7 (21.6 ± 1.5% and 18.2 ± 1.8% for nonstressed and stressed PART embryos; P > 0.05). There was no difference in total cell numbers between nonstressed and stressed IVF or PART embryos. Apoptosis cell numbers and the apoptotic cell index were higher (P < 0.05) for stressed IVF (18.45 ± 1.24 and 0.16 ± 0.00) and PART (16.40 ± 5.20 and 0.17 ± 0.00) embryos than for nonstressed IVF (13.70 ± 0.75 and 0.13 ± 0.00) and PART (14.15 ± 0.86 and 0.13 ± 0.00) embryos. In conclusion, heat stress can induce apoptosis in both IVF and PART embryos, but its effect on pre-implantation development may occur at earlier stages in IVF embryos when compared with PART embryos. Financial support from Fapemig and CNPq.

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Ascophyllum nodosum Supplementation: A Preharvest Intervention for Reducing Escherichia coli O157:H7 and Salmonella spp. in Feedlot Steers

Journal of Food Protection ◽

10.4315/0362-028x-67.9.1824 ◽

2004 ◽

Vol 67 (9) ◽

pp. 1824-1828 ◽

Cited By ~ 53

Author(s):

K. W. BRADEN ◽

J. R. BLANTON ◽

V. G. ALLEN ◽

K. R. POND ◽

M. F. MILLER

Keyword(s):

Escherichia Coli ◽

Dry Matter ◽

Bos Taurus ◽

Bos Indicus ◽

Ascophyllum Nodosum ◽

Feedlot Cattle ◽

Enterohemorrhagic Escherichia Coli ◽

Salmonella Spp ◽

Fecal Samples ◽

Matter Basis

Ascophyllum nodosum (Tasco-14) decreased the prevalence of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in animals fed prior to harvest. Tasco-14 was supplemented on a 2% dry matter basis 14 days prior to harvest to determine its effects on EHEC and Salmonella spp. prevalence. Two hundred mixed crossbred steers and heifers (Bos indicus × Bos taurus), in a large commercial finishing facility, served as experimental units. Treatment (TRT, n = 100) animals received a steam-rolled corn-based diet containing 2% Tasco-14 on a dry matter basis, and control (CON, n = 100) animals received only the steam-rolled corn-based diet. Hide swabs and fecal samples were obtained for EHEC and Salmonella spp. evaluations. Animals were sampled 1 day prior to (d − 1) the feeding of Tasco-14 and immediately following exsanguinations. The prevalence of EHEC O157 on hide swabs and in fecal samples (P = 0.0001 and P < 0.0001, respectively) and the prevalence of EHEC O157:H7 on hide swabs and in fecal samples (P < 0.0001 and P < 0.0001, respectively) was reduced by 33 and 36% from d − 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of EHEC O157 and EHEC O157: H7 was reduced by 33 and 36% from d − 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of Salmonella spp. on hide swabs did not change for TRT animals (P = 0.64). CON animals showed an increase in Salmonella spp. prevalence (P < 0.0001) from d − 1 feeding levels on hide swabs. The prevalence of Salmonella spp. increased in both TRT and CON fecal samples when compared to d − 1 levels (P = 0.002). However, TRT samples exhibited a lower (P < 0.05) postfeeding prevalence of Salmonella spp. in fecal samples than did CON samples. Results from this study indicate that 2% Tasco-14 supplementation in feedlot cattle diets reduces EHEC O157 and EHEC O157:H7 prevalence on hide swabs and in fecal samples and may suppress increases in Salmonella spp.

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