Effect of heat stress on production in Mediterranean dairy sheep

Finocchiaro, R.; Kaam, J.B.C.H.M. van; Sardina, Maria Teresa; Misztal, I.

doi:10.4081/ijas.2005.2s.70

Cited by 39 publications

(49 citation statements)

References 6 publications

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“…However, reports indicate that milk production traits in ewes seem to have a higher negative correlation with the direct values of temperature or relative humidity than THI. The values of THI above which ewes start to suffer from heat stress seem to be quite different among breeds (Finocchiaro et al, 2005). Solar radiation seems to have a limited effect on milk yield, but a greater effect on yield of casein, fat and clot firmness in the milk of Comisana ewes (Sevi et al, 2001).…”

Section: Reproductionmentioning

confidence: 96%

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Bernabucci

Lacetera

Baumgard

et al. 2010

Animal

744

492

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Environmentally induced periods of heat stress decrease productivity with devastating economic consequences to global animal agriculture. Heat stress can be defined as a physiological condition when the core body temperature of a given species exceeds its range specified for normal activity, which results from a total heat load (internal production and environment) exceeding the capacity for heat dissipation and this prompts physiological and behavioral responses to reduce the strain. The ability of ruminants to regulate body temperature is species-and breed-dependent. Dairy breeds are typically more sensitive to heat stress than meat breeds, and higher-producing animals are more susceptible to heat stress because they generate more metabolic heat. During heat stress, ruminants, like other homeothermic animals, increase avenues of heat loss and reduce heat production in an attempt to maintain euthermia. The immediate responses to heat load are increased respiration rates, decreased feed intake and increased water intake. Acclimatization is a process by which animals adapt to environmental conditions and engage behavioral, hormonal and metabolic changes that are characteristics of either acclimatory homeostasis or homeorhetic mechanisms used by the animals to survive in a new 'physiological state'. For example, alterations in the hormonal profile are mainly characterized by a decline and increase in anabolic and catabolic hormones, respectively. The response to heat load and the heat-induced change in homeorhetic modifiers alters post-absorptive energy, lipid and protein metabolism, impairs liver function, causes oxidative stress, jeopardizes the immune response and decreases reproductive performance. These physiological modifications alter nutrient partitioning and may prevent heat-stressed lactating cows from recruiting glucose-sparing mechanisms (despite the reduced nutrient intake). This might explain, in large part, why decreased feed intake only accounts for a minor portion of the reduced milk yield from environmentally induced hyperthermic cows. How these metabolic changes are initiated and regulated is not known. It also remains unclear how these changes differ between short-term v. long-term heat acclimation to impact animal productivity and well-being. A better understanding of the adaptations enlisted by ruminants during heat stress is necessary to enhance the likelihood of developing strategies to simultaneously improve heat tolerance and increase productivity.Keywords: ruminants, heat stress, metabolism, acclimation, adaptation ImplicationsHeat stress is a significant financial burden to animal agriculture in most areas of the world. Acclimation to heat stress imposes behavioral, physiological and metabolic adjustments to reduce the strain and enhances the likelihood of surviving the stress, and it also frequently reduces ruminant performance and compromises health. Improving our knowledge of physiological and metabolic mechanisms of acclimation may contribute to the development and adoption of proce...

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Section: Reproductionmentioning

confidence: 96%

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Bernabucci

Lacetera

Baumgard

et al. 2010

Animal

744

492

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“…In arid regions of the world like that of the present study, such climatic conditions are common during summer and they negatively affect the estrus behaviour, fertility, and productivity of animals (González-Bulnes et al, 2011). Reserach has provided insight into potential means of mitigating the effects of heat stress on reproductive efficiency of domestic animals (Naqvi et al, 2004;Finocchiaro et al, 2005). However, compared with bovines, in sheep the use of strategies to reduce the effect of the heat stress on reproduction efficiency has been very limited.…”

Section: Discussionmentioning

confidence: 99%

“…Some investigations have provided insight into potential means of mitigating the effects of heat stress on reproductive efficiency of sheep. These methods include application of exogenous hormones (Naqvi et al, 2004) and cooling (Finocchiaro et al, 2005). Nevertheless, limited information exists on the use of hormone treatments to induce estrus activity in heat-stressed hair breed ewes or their crosses with prolific wool breeds.…”

mentioning

confidence: 99%

Reproductive efficiency of Pelibuey and Romanov × Pelibuey ewes synchronized with synthetic progesterone and low doses of PMSG under a hot environment

Macías‐Cruz¹,

Ponce-Covarrubias²,

Álvarez-Valenzuela³

et al. 2013

CZECH J ANIM SCI

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Thirty-nine multiparous ewes (19 Pelibuey and 20 Romanov × Pelibuey) treated with fluorogestone acetate impregnated intravaginal sponges were used to evaluate the effects of low pregnant mare serum gonadotropin (PMSG) doses and genotype on their reproductive efficiency under heat stress conditions. The sponge treatment lasted for 12 days, and 24 h before sponge removal, ewes of each genotype were injected with 140 or 280 IU of PMSG. Ewes showing estrus were naturally mated twice. Reproductive performance was not affected (P > 0.05) by the dose × genotype interaction. All treated ewes presented estrus signs within a 48-h period after sponge removal. Shorter (P < 0.05) estrus interval and higher (P < 0.05) fecundity were observed in ewes treated with 280 IU of PMSG compared to those treated with 140 IU. Pelibuey ewes exhibited shorter (P < 0.01) estrus interval and greater (P < 0.01) fertility as compared with Romanov × Pelibuey ewes. The response to estrus, gestation length, prolificacy, and percentage of single and multiple lambing were not affected (P > 0.05) by dose or genotype. In conclusion, under heat stress conditions, low PMSG doses as 140 or 280 IU can be used to successfully induce and/or synchronize the estrus in Pelibuey ewes and their crosses with Romanov, regardless of reduced fertility observed in crossed Pelibuey ewes. If a more predictable and compact estrus is required, administration of 280 IU of PMSG is recommended.

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“…In contrast to dairy and beef cows, less information about the effects of heat stress on sheep and goats is available in the literature, mainly because of their minor importance with regard to world milk production. Approximately 67% of all dairy sheep are located in the Mediterranean region, where heat stress is common during warm summer months (Finocchiaro et al, 2005). Sheep and goats appear to be less susceptible to heat stress than other domesticated ruminant species in relation with unique characteristics such as water conservation capability, potential water loss up to 35% of total body water content (in the Bedouin goat Shkolnik and Choshniak, 2006), higher sweating and respiratory rate and lower basal heat production (Kadzere et al, 2002).…”

Section: Thermoregulatory Responsesmentioning

confidence: 99%

Adaptation to hot climate and strategies to alleviate heat stress in livestock production

Renaudeau¹,

Collin

Yahav

et al. 2012

Animal

789

611

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Despite many challenges faced by animal producers, including environmental problems, diseases, economic pressure, and feed availability, it is still predicted that animal production in developing countries will continue to sustain the future growth of the world's meat production. In these areas, livestock performance is generally lower than those obtained in Western Europe and North America. Although many factors can be involved, climatic factors are among the first and crucial limiting factors of the development of animal production in warm regions. In addition, global warming will further accentuate heat stress-related problems. The objective of this paper was to review the effective strategies to alleviate heat stress in the context of tropical livestock production systems. These strategies can be classified into three groups: those increasing feed intake or decreasing metabolic heat production, those enhancing heat-loss capacities, and those involving genetic selection for heat tolerance. Under heat stress, improved production should be possible through modifications of diet composition that either promotes a higher intake or compensates the low feed consumption. In addition, altering feeding management such as a change in feeding time and/or frequency, are efficient tools to avoid excessive heat load and improve survival rate, especially in poultry. Methods to enhance heat exchange between the environment and the animal and those changing the environment to prevent or limit heat stress can be used to improve performance under hot climatic conditions. Although differences in thermal tolerance exist between livestock species (ruminants . monogastrics), there are also large differences between breeds of a species and within each breed. Consequently, the opportunity may exist to improve thermal tolerance of the animals using genetic tools. However, further research is required to quantify the genetic antagonism between adaptation and production traits to evaluate the potential selection response. With the development of molecular biotechnologies, new opportunities are available to characterize gene expression and identify key cellular responses to heat stress. These new tools will enable scientists to improve the accuracy and the efficiency of selection for heat tolerance. Epigenetic regulation of gene expression and thermal imprinting of the genome could also be an efficient method to improve thermal tolerance. Such techniques (e.g. perinatal heat acclimation) are currently being experimented in chicken.

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Effect of heat stress on production in Mediterranean dairy sheep

Cited by 39 publications

References 6 publications

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Reproductive efficiency of Pelibuey and Romanov × Pelibuey ewes synchronized with synthetic progesterone and low doses of PMSG under a hot environment

Adaptation to hot climate and strategies to alleviate heat stress in livestock production

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