Sprinklers

Cooling cows leads to hormone secretion that increases milk production

Álvaro García

Heat stress in lactating dairy cows leads to physiological responses that affect their well-being and performance. The peculiarity of their digestive system leads to increased heat increment, which further compounds with external environmental warm temperatures.

To cope with this heat overload, cows rely on two main mechanisms. One internal, which is to reduce feed intake and thus heat production, the second external which is to look for cooler spots in the barn or the field. The heat overload affects several aspects of the animal’s physiology, ranging from reductions in productivity, reproductive losses, all the may to increased incidence of digestive upsets.

Dairy farmers in warmer climates tackle this problem with a few different approaches targeting both internal and external sources of heat. One frequent approach (external) is to cool-off cow’s through water sprinklers, forced air through fans or a combination of both. Another approach (internal) is to increase the nutrient density of the diet to account for reduced feed intake. Despite all these efforts there is still always a sensible reduction in intake, which results in a negative energy balance.

A negative energy balance causes hormonal changes such as a reduction in leptin and an increment in ghrelin

This disparity between energy intake and its requirements for production leads to hormonal changes responsible for further drops in intake. One such change is the reduction in leptin and an increase in ghrelin. Leptin synthesized in the adipose tissue has important bearing in eating behavior, energy expenditure, and body weight. It signals the hypothalamus of the adequacy of the energy status in the body, and the need to reduce intake.

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Cute Holstein calf hidden in the grass

Lessening heat stress pre- and post-calving improves dairy calf performance

Alvaro Garcia

Thermostasis is the process by which animals attempt to keep body temperature constant despite changes in environmental temperatures. Heat stress occurs when cows are incapable of dissipating enough heat to maintain their core body temperature. This increase in body temperature results from the combination of heat from the environment and heat increment produced internally during rumen fermentation and nutrient metabolism. In addition, heat stress increases respiratory frequency (panting) to enhance heat dissipation.

Heat increment is greater at higher feed intakes and milk production, which is why high-producing cows are more sensitive to heat stress than their lower-producing counterparts. While there has been extensive research analyzing these effects in mature cows, comparatively little has been done addressing the potential negative consequences on future productivity, health, and reproduction, of their offspring.

Long-term consequences of suffering heat stress in utero and immediately after birth

Aside for shade, pre-weaned calves are not usually considered a priority when heat abatement strategies are implemented in the farm. The main reasons are that they have a larger surface/mass ratio, and not highly significant heat increment, smaller heat loads, when compared to mature cows. However, heat stress in heifer calves both in utero as well as immediately after birth, can have long-term consequences on their future productivity in the herd.

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Lying and eating behavior of Jersey and Holstein cows

Alvaro Garcia

Cow behavior has been the subject of much research in recent years with the intention to optimize their management and well-being. The development of automated devices that constantly monitor the cow’s activity has greatly helped form this perspective. Technologies that measure remotely cattle movements, temperature, rumination, and other physiological parameters have found their way from research facilities into commercial dairy farms.

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Types of bedding and its effects on dairy cattle welfare

Andrés Haro & Fernando Díaz

Dairy farmers use different types of bedding materials such as straw, wood chips, sand or compost. Ample bedding can optimize laying time, reduce hock lesions and lameness, and increase cow longevity. Hard and wet stall surfaces have negative effects on the welfare and behavior of dairy cows.

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Preference of cows to access to an outdoor pack

Fernando Diaz

Consumer preferences along with animal welfare concerns make pasture access for dairy cows an important issue in the dairy industry. Generally, access to pasture does not prove to be an effective option year-round due to environmental constraints. In addition, dairy cows typically prefer to remain indoors during the day and go to pasture at night. Providing cows with free access to an outdoor pack may be an alternative strategy to pasture.

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Improving cow welfare in Canadian dairies

Improving cow welfare in Canadian dairies

Fernando Díaz

In order to improve cow welfare in dairy farms, Canadian researchers conducted a welfare assessment in 250 Holstein dairies from Ontario, Alberta, and Quebec. Minimum herd size consisted of 40 milking cows and the facilities were tie-stall (50%) and free-stall (50%) barns with no access to outdoor pastures.

The assessment included 13 critical areas grouped in three categories:

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