Heat-stress abatement during the dry period: does cooling improve transition into lactation?

نویسندگان

  • B C do Amaral
  • E E Connor
  • S Tao
  • J Hayen
  • J Bubolz
  • G E Dahl
چکیده

Environmental factors, especially temperature and light exposure, influence the health and productivity of dairy cows during lactation, possibly via similar physiological mechanisms. For example, heat stress is a critical component of decreased milk yield during summer. However, less is known about the effect of heat stress during the dry period. The objective of this study was to evaluate the effects of heat stress prepartum under a controlled photoperiod on lactation performance and hepatic metabolic gene expression of periparturient multiparous Holstein cows (n = 16). Cows were dried off approximately 46 d before expected calving date and assigned to treatment randomly after blocking by mature equivalent milk production and parity. Treatments consisted of either heat stress (HT) or cooling (CL) with fans and sprinklers, both under a photoperiod of 14L:10D. Rectal temperature was measured twice daily during the dry period. After calving, cows were housed in a freestall barn with cooling devices, and milk yield was recorded daily up to 210 d in milk. Blood samples were taken from dry off until +42 d relative to calving for metabolites and from -2 until +2 d relative to calving for hormone analysis. Daily dry matter intake was measured from -35 to +42 d relative to calving. Liver biopsies were collected at dry off, -20, +2, and +20 d relative to calving for cows on HT (n = 5) and CL (n = 4) to measure mRNA expression of suppressors of cytokine signaling-2 (SOCS-2), insulin-like growth factor binding protein-5 (IGFBP-5), a key transcription factor in lipid biosynthesis (SREBP-1c), and enzymes of lipid metabolism (FASN, ACACA, and ACADVL) by real-time quantitative PCR. Heat stress increased rectal temperatures (39.2 vs. 38.8 degrees C), plasma prolactin concentrations at -1 (171 vs. 79 ng/mL) and 0 d (210 vs. 115 ng/mL) relative to calving, and decreased dry matter intake at 0 and +14 d relative to calving and 3.5% fat-corrected milk postpartum (26.1 vs. 35.4 kg/d) compared with CL cows. Relative to CL cows, hepatic mRNA expression of SOCS-2 and IGFBP-5 was downregulated in HT cows. Expression of ACADVL was upregulated in CL cows at d +2 but downregulated at d +20 relative to HT cows. Concentrations of C16:0 and cis C18:1 were greater in the milk and liver of CL cows compared with HT cows, which reflects greater lipid mobilization. These results suggest that heat-stress abatement in the dry period improves subsequent lactation, possibly via suppression of plasma prolactin surge around calving, SOCS-2 expression, and regulation of hepatic lipid metabolism.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Heat stress abatement during the dry period influences metabolic gene expression and improves immune status in the transition period of dairy cows.

Heat stress (HT) and photoperiod affect milk production and immune status of dairy cows. The objective was to evaluate the effects of HT abatement prepartum under controlled photoperiod on hepatic metabolic gene expression and cellular immune function of periparturient Holstein cows (n=21). Cows were dried off 46 d before expected calving date and assigned to treatments by mature equivalent mil...

متن کامل

Major advances associated with environmental effects on dairy cattle.

It has long been known that season of the year has major impacts on dairy animal performance measures including growth, reproduction, and lactation. Additionally, as average production per cow has doubled, the metabolic heat output per animal has increased substantially rendering animals more susceptible to heat stress. This, in turn, has altered cooling and housing requirements for cattle. Sub...

متن کامل

Effects of short day photoperiod on prolactin signaling in dry cows: a common mechanism among tissues and environments?

Photoperiodic manipulation has dramatic physiological and production effects in dairy cows. During lactation, exposure to long day photoperiod (LDPP) increases milk yield and circulating IGF-I and prolactin (PRL) concentrations. Conversely, cows housed under a short day photoperiod (SDPP) during the dry period produce more milk in the subsequent lactation than cows exposed to LDPP or natural ph...

متن کامل

Management of photoperiod in the dairy herd for improved production and health.

Environmental influences on lactation efficiency are frequently associated with reductions in milk output. Heat stress, for example, leads to depressed feed intake and, subsequently, losses in production. Conversely, cold stress may limit nutrients available for milk synthesis. Fortunately, one environmental factor, photoperiod, can exert a positive effect on dairy performance when managed prop...

متن کامل

Connecting Transition Cow Physiology, Behavior, and Nutrition

In the past, efforts to improve the transition to lactation have focused largely on preventing infections and maximizing energy intake in transition cows, and these have generally been treated as independent issues. However, new models are emerging to explain the development of numerous transition disorders. A combination of insults, including social stress, negative energy balance, heat stress...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of dairy science

دوره 92 12  شماره 

صفحات  -

تاریخ انتشار 2009