Bonus Tydskrif SPRING SUMMER 2024 FINAL

Addressing heat stress in dairy cows on pasture-based farms Heat stress in dairy cattle is not a new concept. Ongoing research shows the negative financial effect heat stress has on some dairy businesses. Research also suggests that calves born to mothers who experienced heat stress while in calf, may be less productive later in their lives. It is true that the measures that can be practically implemented to reduce heat stress are more suited to TMR (total mixed ration) farming systems and not pasture-based systems. By Mark Willment, technical advisor: Dairy, De Heus There are, however, some measures pasture farms can implement and they are probably more practical than you may think. These strategies are not silver bullets to solve the problem but small changes in timing, infrastructure, and management may lead to many small gains in reducing the negative effect of heat stress, and hopefully have a positive influence on the bottom line. There is no doubt that heat stress occurs on many pasture-based farms. The data collected (Figure 1) from the Log Tag recorders show the temperature humidity index on a farm in the Creighton area of KwaZulu-Natal. The device cannot record wind speed, which would influence the index. However, it still gives us information showing how frequently during the day cows could be experiencing high levels of heat stress. Strategies to reduce heat stress The main strategies of providing shade, wetting cows with water and air movement with fans are not always Heatstress indexreport,January2024 inCreighton.(Source:DeHeus). Feeding strategies There are several additives and feeding strategies to help reduce the effect of heat stress and combat the heat created by rumination. The goal is to assist the rumen in maintaining a healthy rumen environment, maintaining feed intake and managing rumen pH. practical but often impossible. Some paster farmers provide shade for the dairy herd before afternoon milking and during the hottest part of the day when cows are not grazing. Wetting cows removes the heat from the body and helps cool the animal through evaporation. Wetting the cows with a sprinkler in the holding yard can help cool them down. The concrete of the holding yard is often very hot before afternoon milking. Wetting or flooding the concrete to remove the heat before the cows walk into the holding yard could also help reduce the heat. Fans for airflow are not always practical but some measures of improving airflow in the milking parlour might be possible. There are, however, some measures pasture farms can implement and they are probably more practical than you may think. These strategies are not silver bullets to solve the problem but small ch nges in timing, infrastructure, and management may lead to many small gains in reducing the negative effect of heat stress, and hopefully have a positive influence on the bottom line. There is no doubt that heat stress occurs on many pasture-based farms. The data collected (Figure 1) from the Log Tag recorders show the temperature humidity index on a farm i the Creighton area of KwaZulu-N tal. The device cannot record wind speed, which would influ nce t e index. However, i still gives us information showing how frequently during the day cows could be experiencing high levels of heat stress. Strategies to reduce heat stress The main strategies of providing shade, wetting cows with water, and air Some pasture farmers provide shade for the dairy herd before afternoon milking and during the hottest part of the day when cows re not grazing. a Wetting cows removes the heat from the body and helps cool the animal through evaporation. Wetting the cows with a sprinkler in the holding yard can help cool them down. The concrete of the holding yard is often very hot b for after oon milking. Wetting or flooding th concr te to r move the heat before the cows walk into the holding yard could also help reduce the heat. Fans for airflow are not always practical but some measures of improving airflow in the milking parlour might be possible. Feeding strategies There are several additives and feeding strategies to help reduce the effect of heat stress and combat the heat created by rumination. The goal is to assist the rumen in maintaining a healthy rumen environ ent, maintaining feed intake and managi g rumen pH. Heat stress in dairy cattle is not a new concept. Ongoing research shows the negative financial effect heat stress has on some dairy businesses. Research also suggests that calves born to mothers who experienced heat stress while in calf, may be less productive later in their lives. It is true that the measures that can be practically implemented to reduce heat stress are more suited to TMR (total mixed ration) farming systems and not pasture-bas d systems. www.agribonus.co.za movement with fans are not always practical but often impossib e. 34 Winter 2024 BONUS Th re are, howev r, some measures pasture farms can implement and they are probably more practical than you may think. These strategies are not silver bullets to solve the problem but small changes in timing, infrastructure, and management may lead to many small gains in reducing t e negative effect of heat stress, and hopefully have a positive influence on the bottom line. There is no doubt that he t stress occurs on many pasture-based farms. The data collected (Figure 1) from the Log Tag recorders show the temperature humidity index on a farm in the Creighton area of KwaZulu-Natal. The device cannot record wind speed, which would influence the index. However, it still gives us information howing how frequently during the day cows could be experiencing high levels of heat stress. i i i i sha , etti s it t r air movement with fans are not always practical but often not impossible. Some pastur farmers pr vide shade for the dairy herd before afternoon milking and during the hottest part of the day when cows are not grazing. Wetting cows rem ves the heat fro the body and helps cool the animal through evaporation. etting the cows with a sprinkler in the holding yard can help cool them down. The concrete of the holding yard is often very hot before afternoon milking. Wetting or flooding the concrete to remove the heat before the cows walk into the holding yard could also help reduce the heat. Fa s for airflow re not always pr ctical but some me sures of i proving airflow in the milking parlour might be possible. Fe ding strat gies Ther ar several ad itives and feeding str egies to help reduce the effect of heat stress a d comb t the heat created by ru i ation. The go l is to assist the rumen in maintaining a healthy rumen environment, maintaining feed intake and managing rumen pH. www.agribonus.co.za Spring/Summer 2024 BONUS 65