Sprinkler flow rate affects physiological, behavioural and production responses of Holstein cows during heat stress

Abstract

Holstein Friesian cows are known for their high milk yield. They are popular in the commercial dairy sector of Pakistan. Heat stress is a major challenge for these animals owing to the longer summer season with high ambient temperatures (35 - 40 °C) and relative humidity (30 - 50%) in the area (Butt et al., 2020). Mitigating the effects of heat stress requires substantial investments in energy and water. Spraying dairy cows with water in the holding pen or at the feed bunk is common practice as it lowers body temperature and respiration rate (Kendall et al., 2007; Chen et al., 2013; 2016), and improves feed intake and milk yield (Keister et al., 2002). Owing to the recent decrease in global groundwater, studies have focused on strategies to reduce the use of water to cool dairy cows (Chen et al., 2016). Sprinkler flow rates of 1.3 and 4.9 L/min had similar effects on physiological responses of cows to heat load but produced a 73% difference in water use (Chen et al., 2016). Similarly, Tresoldi et al. (2019) concluded that a sprinkler flow rate of 4.9 L/min had poor efficiency compared with 3.3 L/min, as the additional water did not result in increased biologically relevant cooling. These studies were conducted in Mediterranean climates with an average temperature humidity index in the range of 76 to 78. A recent study with Nili Ravi buffaloes revealed a sprinkler flow rate 1.25 L/min was more efficient than one of 2.0 L/min during subtropical summers (Bah et al., 2021). Because water is projected to be scarce in Pakistan by 2030 (Mustafa et al., 2013), holistic strategies for water conservation in the dairy sector are important nationally. The objective of this study was to evaluate the effects of various sprinkler flow rates on the performance of lactating Holstein Friesian cows in a typical corporate dairy farm setting during the subtropical summer. Performance of these cows was assumed to be similar, irrespective of the sprinkler flow rates.

Performance of Holstein cows subjected to different cooling sessions during subtropical summer

“…Each CS lasted for 1 h with a 12 min cycle with 3 min water on and 9 min off. The sprinkler flow rate of 1.25 L/min was used as it efficiently cooled buffaloes [ 4 ] and Holstein Friesian cows [ 11 ]. The experiment lasted for two months (August and September 2019) with a one-week adaptation period.…”

Evaluating the impact of sprinkler cycle and flow rate on dairy buffalo performance during heat stress

“…This is supported by the observed improvements in core body temperatures and respiration rate, all of which are important indicators of animal welfare and productivity. Whilst the difference in respiratory rate between the treatment groups was not substantial, it closely aligned with rates reported in previous studies conducted under similar conditions (Bah et al ., 2021a, 2021b, 2022). Unlike cattle, buffaloes do not primarily rely on respiratory rate as a means to dissipate heat, instead, they employ wallowing behaviour, which facilitates heat dissipation through convection.…”

“…In semi-arid summer, cows cooled with 1.25 and 2.0 l/min flow rates produced similar physiological and productive responses (Bah et al ., 2021a; Macavoray et al ., 2023). While relatively limited research has been conducted on dairy buffaloes, a recent study showed that sprinklers with flow rates of 1.25 and 2.0 l/min resulted in similar physiological and productive responses in buffaloes (Bah et al ., 2021b). Further research in this area could lead to a better understanding of the efficiency of sprinkler cooling in buffaloes, particularly in relation to sprinkler cycles and flow rates.…”

“…Additionally, it improves behavioural responses such as eating time, rumination time and resting time (Chen et al, 2016;Tresoldi et al, 2018b). Recently, researchers have been focusing on improving water usage efficiency in cow cooling (Tresoldi et al, 2018a(Tresoldi et al, , 2018b(Tresoldi et al, , 2019Bah et al, 2021aBah et al, , 2021b as a response to the declining levels of groundwater due to climate change (Taylor et al, 2013). Strategies such as controlling sprinkler flow rate (Chen et al, 2015(Chen et al, , 2016Tresoldi et al, 2019), droplet size (Chen et al, 2015) and sprinkler cycle (Tresoldi et al, 2018b) have been evaluated to optimize the cooling process.…”

On-Farm Water Use Efficiency: Impact of Sprinkler Cycle and Flow Rate to Cool Holstein Cows during Semi-Arid Summer

“…Some studies have shown that flow rates of 1.3 L per minute or higher have a similar effect on cow cooling [10]. A recent study research suggests that flow rates of 2 L per minute or 1.25 L per minute produce a similar effect on cow performance [11]. Spray frequency (cycles) also plays a role in cooling efficiency, as it depends on the duration of the spray (i.e., time water on) and the interval Sustainability 2023, 15, 3774 2 of 16 between sprays when the coat is allowed to dry (time off).…”