Thermal Stress Influence and Seasonal Pattern of Ovarian Follicular Growth Assessed through Ultrasonography in Sunandhini Cows under A Humid Tropical Climate


  •   Cholakkal Ibraheem Kutty

  •   Chirakkal Puthurmadathil Abdul-Azeez

  •   Bibin Bahuleyan Becha

  •   Kanjirakkuzhiyil Promod

  •   Chulliparambil Sunanda

  •   Kundukulam Sunny Anil


The impact of thermal stress (TS) on reproductive processes starts early and persists more extended than the influence on other physiological manifestations. Since the cyclical reproductive activity begins with the growth of ovarian follicles, the present study focused on the effect of TS and its seasonal variations on the growth of ovarian follicles in ‘Sunandhini’ cows reared under the tropical climate. The year-round study was performed on 60 postpartum cows between days 28 to 91, involving eight cows at a time. The cows were replaced sequentially so that the study animals were of almost similar postpartum period throughout the year and formed a continuously changing study group. The ovarian follicular activity of each cow was monitored (nine to ten times) at weekly intervals using B mode ultrasonography. Serum samples collected during the scanning were subjected to ELISA for heat shock protein (HSP) 70 and Cortisol. A comparison of the follicle types, stress indicators, and weather parameters to assess their correlations and seasonal pattern using SPSS software. The maximum temperature of the locality was around 33ºC without significant variation between seasons. Further, the extended rainy season caused moderate to high (66 to 85 %) relative humidity (RH), contributing to a temperature-humidity index (THI) exceeding 78 and putting the animals under moderate to severe TS throughout the year. HSP 70 level showed significant (P<0.001) elevation during summer (6.24 ng/mL), associated with high THI (r=0.701, P<0.001), while serum cortisol had no significant correlation with weather parameters. Only large follicles (9-14 mm) manifested the influence of TS as an increase in number (P<0.05) and size (P<0.01) together with a positive correlation (P<0.01) of HSP 70 and THI. It is inferred that TS causes stagnation of the large follicles from attaining the largest size and functional capability for ovulation. In contrast, other follicle types are unaffected even under moderate to severe TS.

Keywords: Follicular dynamics, season, thermal stress, tropical climate


Kutty CI, Pramod S, Abdul-Azeez CP, Becha BB, Pramod K, Ventakatachalapthy RT. Seasonal Variations in reproductive performance of crossbred cows in Kerala and the influence of climatic stress factors over six years. Theriogenology Insight. 2019; 9: 93-100.

Mader TL, Davis MS, Brown-Brandl, T. Environmental factors influencing heat stress in feedlot cattle. J Anim Sci. 2006; 84: 712-719.

Kutty CI, Azeez CPA, Pramod K, Becha BB, Sunanda C, Lasna S, Ventakatachalapthy RT. The influence of thermal stress on feed intake and body condition score during early postpartum periods of crossbred cows in Kerala.J Vet Anim Sci. 2020a; 51:189-195.

Prasad A. Climatic adaptation and stress evaluation of crossbred cattle of Kerala. Ph.D. Thesis, Kerala Veterinary and Animal Sciences University, Pookode; 2014;160 p.

Sejian V, Maurya VP, Naqvi SM. Adaptability and growth of Malpura ewes subjected to thermal and nutritional stress. Trop AnimHealth and Prod. 2010; 42: 1763-1770.

Torres-Junior JRDS, Pires MDF, De-Sa WF, Ferreira ADM, Viana JHM, Camargo LSA, Baruselli PS. Effect of maternal heat stress on follicular growth and oocyte competence in Bos indicus cattle. Theriogenology.2008; 69: 155 66.

Kumari A, Pampana R. Summer anoestrus in buffaloes – A review. VetClinSci. 2015; 3: 6-10.

Roth Z, Meidan R, Braw-Tal R, Wolfenson D. Immediate and delayed effects of heat stress on follicular development and its association with plasma FSH and inhibin concentration in cows. J ReprodInfertil. 2000; 120: 83-90.

Hansen PJ. Effects of heat stress on mammalian reproduction. Philosophical Transactions Royal Society of Biological Sciences. 2009;364: 3341-3350.

Das R, Sailo L, Verma N, Bharti P, Saikia J, Imtiwati S, Kumar R. Impact of heat stress on health and performance of dairy animals: A review. VetWorld.2016; 9: 260-268.

RashamolPV, Veerasamy R, Madiajagan S. Physiological adaptability of livestock to heat stress: an updated review. JAnimBehBiometeorol. 2018; 6: 62-71.

Goeseels SB, Kastelic JP. Factors affecting embryo survival and strategies to reduce embryonic mortality in cattle. Canadian JAnimSci.2003; 83: 659 - 671.

Kutty CI. Impact of environmental adversities on animal reproduction. In Proceedings of the World Veterinary Day, Thrissur, April 2020; pp. 297-300.

Al-Katanani YM, Webb DW, Hansen PJ. Factors affecting seasonal variation in 90 days' non-return rate to the first service in lactating Holstein cows in a hot climate. JDairy Sci. 1999; 82: 2611-2615.

Sonmez M, Demirci E, Turk G, Gur S. Effect of season on some fertility parameters of dairy and beef cows in Elazig province.Turkish JVetAnimSci.2005; 29: 821-828.

Kumar MS, Rao S. The impact of climatic factors on livestock performance; In Rao GSLHVP, Varma GG. Fundamentals of Livestock Meteorology, Centre for Animal Adaptation to Environment and Climate Change Studies, Kerala Veterinary and Animal Sciences University, Pookode. 2013. pp. 247-254.

Schuller LK, Burfeind O, Heuwieser W. Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature-humidity index thresholds, periods relative to breeding, and heat load indices. Theriogenology 2014; 81: 1050-1057.

Wolfenson D, Roth Z, Meidan R. Impaired reproduction in heat-stressed cattle: basic and applied aspects. Anim Reprod Sci. 2000; 60: 535-547.

Ginther OJ, Kastelic JP, Knop L. Intraovarian relationships among dominant and subordinate follicles and the corpus luteum in heifers. Theriogenology. 1989; 32:787-795.

Krishnan G, Bath M, Pragna P, Vidya MK, Aleena J, Archana R, Bhatta R. Mitigation of the heat stress impact on livestock reproduction, In: Carreira, R. P., editor, Theriogenology [Internet]. London: IntechOpen; 2017:63-86.

Schuller LK, Michaelis I, Heuwieser W. Impact of heat stress on estrus expression and follicle size under field conditions in dairy cows. Theriogenology.2017; 102: 48-53.

ICAR-NIANP. Nutrient requirements of animals-Cattle and Buffalo; NIANP 2013. 58 p.

Kutty CI, Becha BB, Venkatachalapathy RT, Azeez CPA. LRST model movable trevis, A novel method to restrain cattle in barns. Indian J Anim Sci. 2020b; 90: 1556-1559.

Wolfenson D, Thatcher WW, Badinga L, Savio JD, Meidan R, Lew BJ, Berman A. Effect of heat stress on follicular development during the estrous cycle in lactating dairy cattle. Biol Reprod.1995; 52: 1106-1113.

Sartorelli ES, Carvalho LM, Bergfelt DR, Ginther OJ, Barros CM. Morphological characterization of follicle deviation in Nellore (Bos indicus) heifers and cows. Theriogenology. 2005; 63: 2382-2394.

Ginther OJ. Theory of follicle selection in cattle. Dom Anim Endocrinol.2016; 57: 85-99.

LPHSI. The livestock and poultry heat stress indices for cattle, sheep, and goats. In: The agriculture engineering technology guide. Clemson University, Clemson, U.S.A. 1990.

Kutty CI. Role of climate in the reproductive pattern of small ruminants in humid tropics. In: Rao GSLHVP, Varma GG. Fundamentals of Livestock Meteorology, Vol. II., Centre for Animal Adaptation to Environment and Climate Change Studies, Kerala Veterinary and Animal Sciences University, Pookode. 2013; pp. 194-202.

Kutty CI. The uniqueness of seasons in Kerala – Implications on thermal stress and productivity of animals in Kerala. J Vet Anim Sci. 2021; 52: 48-54.

Collier RJ, Renquist BJ, Xiao YA. 100-Year Review: Stress physiology including heat stress. J Dairy Sci.2017; 100: 10367-10380.

Maciel SM, Chamberlain CS, Wettemann RP, Spicer LJ. Dexamethasone influences endocrine and ovarian function in dairy cattle. J Dairy Sci. 2001; 84: 1998-2009.

Silanikove N. Effects of heat stress on the welfare of extensively managed domestic ruminants. Livestock Prod Sci. 2000; 67:11-18.

Badinga L, Thatcher WW, Diaz T, Drost M, Wolfenson D. Effect of environmental heat stress on follicular development and steroidogenesis in lactating Holstein cows. Theriogenology. 1993); 39: 797-810.

Trout J P, McDowell L R, Hansen PJ. Characteristics of the estrous cycle and antioxidant status of lactating Holstein cows exposed to heat stress. J Dairy Sci. 1998; 81: 1244-1250.

Wilson SJ, Marion RS, Spain JN, Spiers DE, Keisler DH, Lucy MC. Effects of controlled heat stress on ovarian function of dairy cattle. J Dairy Sci.1998); 81: 2124-2131.

Kutty CI. Prolonged oestrus in AI bred cattle – The contribution from delayed luteinization of preovulatory follicles. In Proceedings of the 12th Kerala Veterinary Science Congress, India. Nov 2020; pp. 117-119.

Lopez-Gatius F, Lopez-Bejar M, Fenech M, Hunter RH. Ovulation failure and double ovulation in dairy cattle: Risk factors and effects. Theriogenology, 2005, 63:1298-1307.

De-Rensis F, Scaramuzzi RJ. Heat stress and seasonal effects on reproduction in the dairy cow: a review. Theriogenology.2003; 60: 1139-1151.

De-Rensis F, Ispierto I, Lopez-Gatius F. Seasonal heat stress: Clinical implications and hormone treatments for the fertility of dairy cows. Theriogenology.2015; 84: 659-666.

[Data set] *Cholakkal, Ibraheem Kutty. “Thermal stress study”, Mendeley Data VI 2022; DOI: 10.17632/c7ks6t3nd7.1.


How to Cite
Kutty, C. I., Abdul-Azeez, C. P., Becha, B. B., Promod, K., Sunanda, C., & Anil, K. S. (2022). Thermal Stress Influence and Seasonal Pattern of Ovarian Follicular Growth Assessed through Ultrasonography in Sunandhini Cows under A Humid Tropical Climate. European Journal of Veterinary Medicine, 2(5), 16–21.