“…As summarized in Fig. 2, dairy cows exposed to HS produce less milk compared to others kept under HS-free conditions in different regions of the globe (Min et al 2015; Rhoads et al 2009; Cowley et al 2015; Eslamizad et al 2015; Ominski et al 2002; Karimi et al 2015; Flamenbaum and Galon 2010; Soriani et al 2013). A better understanding of the mechanisms whereby HS adversely affects dairy cows is necessary to increase the chances that suitable strategies will be developed to alleviate HS.Fig.…”
Section: Introductionmentioning
confidence: 99%
“…A better understanding of the mechanisms whereby HS adversely affects dairy cows is necessary to increase the chances that suitable strategies will be developed to alleviate HS.Fig. 2Summary of published studies showed the effect of HS and HS-free environment on milk production from different regions of the globe (Min et al 2015; Rhoads et al 2009; Cowley et al 2015; Eslamizad et al 2015; Ominski et al 2002; Karimi et al 2015; Flamenbaum and Galon 2010; Soriani et al 2013). The data from Australia were converted as follows: 1 L/day = 1.0288 kg/day
…”
Heat stress (HS) negatively affects various industries that rely on animal husbandry, particularly the dairy industry. A better understanding of metabolic responses in HS dairy cows is necessary to elucidate the physiological mechanisms of HS and offer a new perspective for future research. In this paper, we review the current knowledge of responses of body metabolism (lipid, carbohydrate, and protein), endocrine profiles, and bovine mammary epithelial cells during HS. Furthermore, we summarize the metabolomics and proteomics data that have revealed the metabolite profiles and differentially expressed proteins that are a feature of HS in dairy cows. Analysis of metabolic changes and “omics” data demonstrated that HS is characterized by reduced lipolysis, increased glycolysis, and catabolism of amino acids in dairy cows. Here, analysis of the impairment of immune function during HS and of the inflammation that arises after long-term HS might suggest new strategies to ameliorate the effects of HS in dairy production.
“…As summarized in Fig. 2, dairy cows exposed to HS produce less milk compared to others kept under HS-free conditions in different regions of the globe (Min et al 2015; Rhoads et al 2009; Cowley et al 2015; Eslamizad et al 2015; Ominski et al 2002; Karimi et al 2015; Flamenbaum and Galon 2010; Soriani et al 2013). A better understanding of the mechanisms whereby HS adversely affects dairy cows is necessary to increase the chances that suitable strategies will be developed to alleviate HS.Fig.…”
Section: Introductionmentioning
confidence: 99%
“…A better understanding of the mechanisms whereby HS adversely affects dairy cows is necessary to increase the chances that suitable strategies will be developed to alleviate HS.Fig. 2Summary of published studies showed the effect of HS and HS-free environment on milk production from different regions of the globe (Min et al 2015; Rhoads et al 2009; Cowley et al 2015; Eslamizad et al 2015; Ominski et al 2002; Karimi et al 2015; Flamenbaum and Galon 2010; Soriani et al 2013). The data from Australia were converted as follows: 1 L/day = 1.0288 kg/day
…”
Heat stress (HS) negatively affects various industries that rely on animal husbandry, particularly the dairy industry. A better understanding of metabolic responses in HS dairy cows is necessary to elucidate the physiological mechanisms of HS and offer a new perspective for future research. In this paper, we review the current knowledge of responses of body metabolism (lipid, carbohydrate, and protein), endocrine profiles, and bovine mammary epithelial cells during HS. Furthermore, we summarize the metabolomics and proteomics data that have revealed the metabolite profiles and differentially expressed proteins that are a feature of HS in dairy cows. Analysis of metabolic changes and “omics” data demonstrated that HS is characterized by reduced lipolysis, increased glycolysis, and catabolism of amino acids in dairy cows. Here, analysis of the impairment of immune function during HS and of the inflammation that arises after long-term HS might suggest new strategies to ameliorate the effects of HS in dairy production.
“…Wall (2015 and found decreased milk and fat corrected milk yields and quality as THI increased. Decreases in DMI under conditions of heat stress are associated with decreases in daily and resting metabolic heat production, longer digestion times, and a shift from fat to glucose utilization in dairy cows (Eslamizad et al, 2015). Means in the same row with different superscripts differ, (P≤0.05).…”
Nine hundreds of lactating Holstein cows in three locations (300 cows at each location) were used to evaluate the effect of nutrition and temperature humidity index (THI) conditions on dairy cattle performance (milk production and composition, digestibility, rumination, rumen pH). Three rations (chemically varied in physical effective NDF (peNDF), neutral detergent fiber (NDF), starch, dietary cation anion difference (DCAD), forage to concentrate ratio (F:C), crude protein (CP), either extract (EE), acid detergent fiber (ADF) and non fiber carbohydrates (NFC) were used at the three locations (R1 in L1, R2 in L2 and R3 in L3). Reviewing the nutritional and THI conditions of dairy farming systems in three countries in the Middle East and provides an up-to-date description of farming systems in these countries. Due to the common dairy farming problems in the region, the study focuses on three countries: Sudan (L1), Lebanon (L2) and Kuwait (L3) for an in-depth evaluation of the nutritional and THI conditions of dairy farming systems. The results indicated that increasing the intake of peNDF increase rumination and ruminal pH, but did not affect intake of DM or NDF. So, the models of those predict rumen pH should include both peNDF and fermentable organic matter (OM) intake. Dietary particle size expressed as peNDF, was a reliable indicator of rumination activity. The digestibility of dry matter (DM), CP, EE and NDF increased as concentrations of CP and NFC increased in the ration. While, the digestibility of OM, NFC and ADF was decreased. Milk production and composition negatively affected by increasing of THI. As the THI increased from 63 to 76; the animal performance decreased either in dry matter intake (DMI) and milk production and composition.
“…In a recent study it has been shown that pre- and post-partum cows respond to exposure to high ambient temperatures (28°C) kept under well-controlled climate chamber conditions with a significant decrease in feed intake and reduced daily and resting metabolic heat production compared to control animals housed under thermoneutral (15°C) conditions [ 10 ]. To distinguish the effect of heat from the unavoidable accompanying effects of reduced feed intake during higher ambient temperatures, a revised HS animal model with pair-fed (PF) cows as control group has been developed ensuring equal energy intake at different temperature conditions [ 11 , 12 ].…”
High environmental temperatures induce detrimental effects on various reproductive processes in cattle. According to the predicted global warming the number of days with unfavorable ambient temperatures will further increase. The objective of this study was to investigate effects of acute heat stress during the late pre-ovulatory phase on morphological, physiological and molecular parameters of dominant follicles in cycling cows during lactation. Eight German Holstein cows in established lactation were exposed to heat stress (28°C) or thermoneutral conditions (15°C) with pair-feeding for four days. After hormonal heat induction growth of the respective dominant follicles was monitored by ultrasonography for two days, then an ovulatory GnRH dose was given and follicular steroid hormones and granulosa cell-specific gene expression profiles were determined 23 hrs thereafter. The data showed that the pre-ovulatory growth of dominant follicles and the estradiol, but not the progesterone concentrations tended to be slightly affected. mRNA microarray and hierarchical cluster analysis revealed distinct expression profiles in granulosa cells derived from heat stressed compared to pair-fed animals. Among the 255 affected genes heatstress-, stress- or apoptosis associated genes were not present. But instead, we found up-regulation of genes essentially involved in G-protein coupled signaling pathways, extracellular matrix composition, and several members of the solute carrier family as well as up-regulation of FST encoding follistatin. In summary, the data of the present study show that acute pre-ovulatory heat stress can specifically alter gene expression profiles in granulosa cells, however without inducing stress related genes and pathways and suggestively can impair follicular growth due to affecting the activin-inhibin-follistatin system.
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