Calving in a Punjab Summer — Keeping Dry and Close-Up Cows and Buffaloes Cool
By Vikas Industrial Corporation, Khanna, Punjab
Heat in the last weeks of pregnancy hurts the cow, the next lactation and the calf. How to read THI for Punjab's dry May–June heat and humid monsoon, and which cooling steps research supports.
Heat in the dry period is not free
It is easy to think a dry animal can wait out the summer because she is not giving milk. Research says otherwise. In a controlled trial at the University of Florida, 16 Holstein cows were dried off about 46 days before calving. Some were cooled with fans and sprinklers and some were not. The uncooled cows had higher body temperatures (39.2 against 38.8°C), ate less around calving and 2 weeks after it, and gave less milk after calving: 26.1 against 35.4 kg a day of fat-corrected milk (do Amaral et al., 2009). It was a small trial under controlled conditions, so do not expect exactly the same gap on your farm. The direction, though, is clear: cooling in the dry period helps the next lactation.
The calf pays too
Heat stress in late pregnancy also reaches the unborn calf. In a later University of Florida study, uncooled dry cows were breathing about 67 times a minute against 43 for cooled cows, and bull calves from the uncooled cows weighed 1.1 kg less at birth and had lighter thymus, spleen and heart (Ahmed et al., 2021). The thymus and spleen are part of the immune system, which may be one reason calves from heat-stressed mothers fight infection less well. Counting breaths is a free warning sign: in that study cooled cows breathed about 43 times a minute and uncooled cows about 67, so a dry animal that is breathing at the higher rate while resting in shade is struggling.
What Indian research shows
Indian studies on transition animals are fewer, but they point the same way. At NDRI Karnal, Sahiwal cows that calved in summer, at a THI of 79.9, showed more signs of programmed death in their immune cells than cows that calved at 67.3 (Somal et al., 2015). Studies of the Murrah herd at Karnal found that fertility traits worsen once THI passes 75, with a critical heat-stress zone from about 80 (Dash et al., 2015). Both studies were done on research herds, with small samples or breeding values, so they show a risk rather than measure the loss on your farm.
Reading the THI in Punjab
The temperature-humidity index (THI) combines temperature and humidity into one number: THI = (1.8 × T + 32) − (0.55 − 0.0055 × RH) × (1.8 × T − 26), with T in °C and RH in percent. Worked examples from this formula show how little relief the year gives. A dry pre-monsoon afternoon of 42°C and 20 percent humidity gives a THI of about 86. A monsoon afternoon of 35°C and 70 percent gives about 89. Even a muggy monsoon night at 29°C and 85 percent gives about 82, so animals get little overnight recovery, and a pleasant day of 28°C and 50 percent already gives about 76. A study of two very different climates found that humidity limits heat loss most in humid climates and temperature in dry ones (Bohmanova et al., 2007), and Punjab has both: dry Loo heat before the monsoon and humid heat during it. Published thresholds vary with breed, outcome and index; NDRI used 75 for Murrah fertility, and our heat stress article uses 68 as the starting point for crossbred cows.
Cooling that works: shade, air, then water
A review of heat stress research found that shade, well-ventilated barns, and the addition of fans and sprinklers lower body heat and improve feed intake (West, 2003). For buffaloes, ICAR-NDRI compared six ways of cooling 84 lactating Murrah buffaloes at THI 82 to 85 against animals left in the open. A shower system worked best at lowering body-surface temperature, milk cortisol and somatic cell count, followed by a water pond and then a mist-and-fan system (Choudhary et al., 2025). In Lahore, on the same Punjab plains, buffaloes cooled by sprinklers five times a day gave 1.6 kg more milk a day than those cooled three times and 3.2 kg more than those given a hosepipe wash twice a day (Hussain et al., 2023a). A second small Lahore trial found sprinklers running 3 minutes on and 3 minutes off beat longer pauses (Hussain et al., 2023b). Both buffalo trials used milking animals. We found no trial of these methods in dry buffaloes, but the principle of keeping the body wet and the air moving is the same.
Feed and water in the heat
Heat lowers intake, so the ration has to be reformulated: it needs more nutrient density, no nutrient excesses, and a rumen that keeps working normally (West, 2003). For close-up animals that means asking your vet or feed adviser to adjust the ration, not simply adding more grain, which can upset the rumen. Shift feeding towards the cooler evening, night and early morning, as described in our heat stress article, and keep clean, cool drinking water in front of every animal at all times.
A calving-pen plan for summer
About 3 weeks before the expected date, move the animal to the best-ventilated, shaded pen and begin cooling when conditions reach the heat-stress zone, not after she is already panting. For cows use shade with fans and sprinklers; for buffaloes use showers or a clean water pond for wallowing. Keep the calving area clean, dry and airy, because high environmental temperature is listed as a risk factor for retained placenta (MSD Veterinary Manual). Count breaths once a day and use shade and water to bring the rate down.
What the evidence does not tell us
The dry-cow cooling trials we found are from Holsteins in Florida. The Indian studies we found cover Sahiwal immune cells, Murrah fertility and milking buffaloes. As far as we could find, nobody has yet measured the effect of dry-period cooling on Punjab crossbred cows or buffaloes. Use these results as a strong reason to cool close-up animals, not as a promise of a particular gain.
Heat in the last 3 weeks of pregnancy costs milk, calf quality and fertility. Watch the THI, count breaths, cool with shade, air and water (showers or a clean pond for buffaloes), and plan summer and monsoon calvings before the animal reaches the pen.
Sources
Figures in this article come from the published sources below. Each link opens the original paper or reference page.
- do Amaral BC, et al. (2009). Heat-stress abatement during the dry period: does cooling improve transition into lactation? Journal of Dairy Science 92:5988–5999.
- Ahmed BMS, et al. (2021). Maternal heat stress reduces body and organ growth in calves: relationship to immune status. JDS Communications 2:295–299.
- Somal A, Aggarwal A, Upadhyay RC (2015). Effect of thermal stress on expression profile of apoptosis related genes in peripheral blood mononuclear cells of transition Sahiwal cow. Iranian Journal of Veterinary Research 16:137–143.
- Dash S, et al. (2015). Assessment of expected breeding values for fertility traits of Murrah buffaloes under subtropical climate. Veterinary World 8:320–325.
- Bohmanova J, Misztal I, Cole JB (2007). Temperature-humidity indices as indicators of milk production losses due to heat stress. Journal of Dairy Science 90:1947–1956.
- West JW (2003). Effects of heat-stress on production in dairy cattle. Journal of Dairy Science 86:2131–2144.
- Choudhary M, et al. (2025). Effect of different heat mitigation strategies on the thermography of lactating water buffaloes during summer seasons under tropical conditions. International Journal of Biometeorology 69:3061–3072.
- Hussain SI, et al. (2023a). Heat stress mitigation: impact of increased cooling sessions on milk yield and welfare of dairy buffaloes in a semiarid summer. Animals 13:3315.
- Hussain SI, et al. (2023b). Evaluating the impact of sprinkler cycle and flow rate on dairy buffalo performance during heat stress. Journal of Dairy Research 90:357–362.
- MSD Veterinary Manual. Retained fetal membranes in cows.