Evaporative cooling for Holstein dairy cows under grazing conditions

Abstract

Twenty-four grazing Holstein cows in mid and late lactation were randomly assigned to two treatment groups: control and cooled. The trial was performed at the Experimental Dairy Unit, Rafaela Agricultural Experimental Station (INTA), Argentina. The objective was to evaluate the effects of sprinkler and fan cooling before milkings on milk production and composition. The effects of the cooling system on rectal temperature and respiration rate were also evaluated. Cooled cows showed higher milk production (1.04 l cow(-1) day(-1)). The concentration and yield of milk fat and protein increased in response to cooling treatment. The cooling system also reduced rectal temperature and respiration rate. No effects were observed on body condition. It was concluded that evaporative cooling, which is efficient for housed animals, is also appropriate to improve yields and animal well-being under grazing systems. These results are impressive since the cooling system was utilized only before milkings, in a system where environmental control is very difficult to achieve. This trial was performed during a mild summer. The results would probably be magnified during hotter weather.

Diet and cooling interactions on physiological responses of grazing dairy cows, milk production and composition

“…1). These observations suggest that the use of a sprinkler and fan system prior to milking under grazing conditions could be effective when animals are cooled for only 50 min/day (Valtorta and Gallardo 2004). This response would be more evident when balanced diets were offered.…”

“…The effect of hot humid weather represents high costs to dairy farmers. There is not only a decrease in milk yields during hot weather (Valtorta et al 1997;Valtorta and Gallardo 2004;West 2003)-milk also has a lower solids content, and cows show impaired reproductive performance and greater susceptibility to ill-health (West 1995). Two important aspects related to hot weather management for lactating dairy cows are: (1) management of the cow environment, and (2) feeding management.…”

“…In hot and humid climates, such as those in Georgia (West 1999) and the Argentine central milk supply area (Valtorta and Gallardo 2004), additional benefits from the combination of sprinklers and fans may be achieved.…”

Water Salinity Under Heat Stress in Grazing Conditions

“…With respect to the direct cooling of the animal, using a system as described, in Argentina the effectiveness of pre-milking refrigeration has been evaluated (Valtorta & Gallardo, 2004). Cows were cooled for 20 min prior to both milkings through a combination of sprinkling and continuous ventilation.…”

Short Communication Association of ATP1A1 gene polymorphism with heat tolerance traits in dairy cattle

“…There are many forms of evidence indicating that the optimum temperature of lactating cows is -5 ~20ºC (Valtorta and Gallardo, 2004). Cows suffer heat shock when the temperature is above 20ºC, and milk yields decline significantly.…”