Influence of heat stress or feed restriction on plasma progesterone, oestradiol-17β, LH, FSH, prolactin and cortisol in Holstein heifers

Ronchi, Bruno; Stradaioli, G.; Supplizi, Andrea Verini; Bernabucci, U.; Lacetera, Nicola; Accorsi, Pier Attilio; Nardone, A.; Seren, E.

doi:10.1016/s0301-6226(00)00232-3

Cited by 141 publications

(120 citation statements)

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“…Corticotropinreleasing hormone stimulates somatostatin; possibly a key mechanism by which heat-stressed animals have reduced GH and thyroid levels (Riedel et al, 1998). In dairy cattle, the glucocorticoids decrease during acclimation at 358C (Alvarez and Johnson, 1973) and are lower in thermal-acclimated animals compared with controls (Ronchi et al, 2001).…”

Section: Heat Stress In Ruminants 1171mentioning

confidence: 99%

“…In females, heat stress compromises oocyte growth by altering progesterone, luteinizing hormone and follicle-stimulating hormone secretion and dynamics during the estrous cycle (Ronchi et al, 2001). Moreover, heat stress may reduce summer fertility in dairy and beef cows by causing poor estrous expression due to reduced estradiol secretion from the dominant follicle developed in a low luteinizing hormone environment (Biggers et al, 1987; De Rensis and Scaramuzzi, 2003;Amundson et al, 2006).…”

Section: Reproductionmentioning

confidence: 99%

“…Circulating prolactin levels are increased during thermal stress in a variety of mammals including ruminants (Collier et al, 1982a;Ronchi et al, 2001;Roy and Prakash, 2007). This is paradoxical as reduced nutrient intake in thermal neutral ruminants decreases circulating prolactin concentrations (Bocquier et al, 1998).…”

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

“…This is paradoxical as reduced nutrient intake in thermal neutral ruminants decreases circulating prolactin concentrations (Bocquier et al, 1998). A direct (independent of reduced feed intake) effect of heat stress on serum prolactin levels has been shown (Ronchi et al, 2001). Increased prolactin initially seems contradictory (especially in lactating dairy cows), given prolactin's well-known role in maintaining galactopoiesis in some species and lactogenesis in ruminants, but prolactin may play an important role in acclimation through improved insensible heat loss and sweat gland function (Beede and Collier, 1986).…”

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

“…The thyroid hormones, T4 and T3, provide a major mechanism important for acclimation and have received considerable research attention. It is well known that heat acclimation decreases endogenous levels of thyroid hormones (in an attempt to reduce endogenous heat production) and those mammals adapted to warmer climates follow this pattern (Johnson and Vanjonack, 1976;Horowitz, 2001).Circulating prolactin levels are increased during thermal stress in a variety of mammals including ruminants (Collier et al, 1982a;Ronchi et al, 2001;Roy and Prakash, 2007). This is paradoxical as reduced nutrient intake in thermal neutral ruminants decreases circulating prolactin concentrations (Bocquier et al, 1998).…”

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confidence: 99%

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Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Bernabucci

Lacetera

Baumgard

et al. 2010

Animal

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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: Heat Stress In Ruminants 1171mentioning

confidence: 99%

Section: Reproductionmentioning

confidence: 99%

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

Section: Metabolic and Hormonal Acclimation To Hot Environmentmentioning

confidence: 99%

mentioning

confidence: 99%

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Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Bernabucci

Lacetera

Baumgard

et al. 2010

Animal

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718

492

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Endocrinology of year‐round reproduction in a highly seasonal habitat: Environmental variability in testosterone and glucocorticoids in baboon males

Gesquiere

Onyango

Alberts

et al. 2010

American J Phys Anthropol

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In conditions characterized by energetic constraints, such as in periods of low food availability, some trade-offs between reproduction and self-maintenance may be necessary; even year-round breeders may then be forced to exhibit some reproductive seasonality. Prior research has largely focused on female reproduction and physiology, and few studies have evaluated the impact of environmental factors on males. Here we assessed the effects of season and ambient temperatures on fecal glucocorticoid (fGC) and testosterone (fT) levels in male baboons in Amboseli, Kenya. The Amboseli basin is a highly challenging, semi-arid tropical habitat that is characterized by strongly seasonal patterns of rainfall and by high ambient temperatures. We previously reported that female baboons were impacted by these challenging environmental conditions. We ask here whether male baboons in the same environment and groups as females exhibit similar physiological effects. We found that after accounting for male age and individual variability, males exhibited higher fGC levels and lower fT levels during the dry season than during the wet season. Furthermore, fT but not fGC levels were lower in months of high average daily maximum temperatures, suggesting a direct impact of heat on testes. Our results demonstrate that male baboons, like females, experience ecological stress that alters their reproductive physiology. The impact of the environment on male reproduction deserves more attention both in its own right and because alteration in male physiology may contribute to the reduction in female fertility observed in challenging environments.

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Heat stress, a serious threat to reproductive function in animals and humans

Boni

2019

Molecular Reproduction Devel

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Global warming represents a major stressful environmental condition that compromises the reproductive efficiency of animals and humans via a rise of body temperature above its physiological homeothermic point (heat stress [HS]). The injuries caused by HS on reproductive function involves both male and female components, fertilization mechanisms as well as the early and late stages of embryofetal development. This occurrence causes great economic damage in livestock, and, in wild animals creates selective pressure towards the advantages of better-adapted genotypes to the detriment of others. Humans undergo several types of stress, including heat, and these represent putative causes of ongoing progressive decay in procreation; an increasing number of remedies in the form of antioxidant preparations are now being proposed to counteract the effects of stress. This review aims to describe the results of the most recent studies that aimed to highlight these effects and to draw information on the mechanisms acting as the basis of this problem from a comparative analysis. K E Y W O R D S follicle, global warming, heat stress, mitochondria, oocyte, reproductive activity, spermatozoa Mol Reprod Dev. 2019;86:1307-1323.wileyonlinelibrary.com/journal/mrd

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Influence of heat stress or feed restriction on plasma progesterone, oestradiol-17β, LH, FSH, prolactin and cortisol in Holstein heifers

Cited by 141 publications

References 31 publications

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Metabolic and hormonal acclimation to heat stress in domesticated ruminants

Endocrinology of year‐round reproduction in a highly seasonal habitat: Environmental variability in testosterone and glucocorticoids in baboon males

Heat stress, a serious threat to reproductive function in animals and humans

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