Characterization of Short-Term Heat Stress in Holstein Dairy Cows Using Altered Indicators of Metabolomics, Blood Parameters, Milk MicroRNA-216 and Characteristics

Abstract

This study aims to characterize the influence of short-term heat stress (HS; 4 day) in early lactating Holstein dairy cows, in terms of triggering blood metabolomics and parameters, milk yield and composition, and milk microRNA expression. Eight cows (milk yield = 30 ± 1.5 kg/day, parity = 1.09 ± 0.05) were homogeneously housed in environmentally controlled chambers, assigned into two groups with respect to the temperature humidity index (THI) at two distinct levels: approximately ~71 (low-temperature, low-humidity; LTLH) and ~86 (high-temperature, high-humidity; HTHH). Average feed intake (FI) dropped about 10 kg in the HTHH group, compared with the LTLH group (p = 0.001), whereas water intake was only numerically higher (p = 0.183) in the HTHH group than in the LTLH group. Physiological parameters, including rectal temperature (p = 0.001) and heart rate (p = 0.038), were significantly higher in the HTHH group than in the LTLH group. Plasma cortisol and haptoglobin were higher (p < 0.05) in the HTHH group, compared to the LTLH group. Milk yield, milk fat yield, 3.5% fat-corrected milk (FCM), and energy-corrected milk (ECM) were lower (p < 0.05) in the HTHH group than in the LTLH group. Higher relative expression of milk miRNA-216 was observed in the HTHH group (p < 0.05). Valine, isoleucine, methionine, phenylalanine, tyrosine, tryptophan, lactic acid, 3-phenylpropionic acid, 1,5-anhydro-D-sorbitol, myo-inositol, and urea were decreased (p < 0.05). These results suggest that early lactating cows are more vulnerable to short-term (4 day) high THI levels—that is, HTHH conditions—compared with LTLH, considering the enormous negative effects observed in measured blood metabolomics and parameters, milk yield and compositions, and milk miRNA-216 expression.

Effects of Heat Stress in Dairy Cows Offered Diets Containing Either Wheat or Corn Grain during Late Lactation

“…The observed changes in DMI, milk yield and physiology responses are consistent with these cows experiencing heat stress [ 26 ] as intended. Our results are consistent with previous studies that also reported declines in DMI [ 19 , 28 , 29 ] and milk yield [ 13 , 19 , 30 ] between the pre-challenge and heat challenge periods. In our experiment, the concentrations of milk fat and lactose were greater during the heat challenge.…”

The Role of microRNAs in the Mammary Gland Development, Health, and Function of Cattle, Goats, and Sheep

“…As for the direct epigenetic responses to heat stress in the mammary gland, miR-216b has been found to inhibit the heat-stress-induced apoptosis of mammary epithelial cells under heat stress [254]. It has also been observed that miR-216 is more strongly expressed in cows with an increase in not only temperature but also air humidity [255]. In the previously mentioned study by Li et al (2018), in addition to finding 139 new miRNAs, the epigenetic responses to heat stress in cows were also studied, and it was observed that the expression of miR-145, miR-133a, and miR-29c was increased in the heat-stress group.…”

Estimating losses in milk production by heat stress and environmental impacts of greenhouse gas emissions in Korean dairy farms

“…Given this, increasing milk quality and quantity can result in additional income enabling farmers to improve the systems or facilities to decrease HS in dairy cattle [37]. Previous researches have documented the effect of HS on milk quality in dairy cattle [23,25,38].…”