Introduction
The integumentary system consists of the skin and other related appendages that work together to safeguard the body from damage. These appendages include scales, hair, hooves, feathers, nails, glands, and nerves. They confer protection against water, heat loss, infection, and injury to internal tissues. Additional functions include the excretion of waste substances, maintenance of body temperature, and anchoring sensory nerves to aid in the perception of touch, pain, pressure, and temperature alterations.[1] When vertebrates are exposed to sunshine, the integumentary system makes it possible to synthesize vitamin D. In animal rearing, and the integument dictates the treatment and handling of animals to ensure optimal health and production. The purpose of this paper is to explain the physiological function of the integumentary system of dairy cattle and its impact on housing. Modern developments in animal housing and management systems to cater to the physical needs of dairy cattle are also explained.
Physiological functioning of dairy cattle and its influence on animal housing
Dairy cattle consume less feed under heat stress, which leads to reduced body growth and low milk production. Extreme temperatures also have adverse effects on the reproduction of these animals. Therefore, the design of animal housing mainly focuses on the physical surroundings with regard to climatic and motor attributes. Nonetheless, it is important to consider other aspects such as optimal layout to provide the best conditions for high-yielding animals to feed properly and produce without experiencing physical harm.
With regard to heat regulation, dairy cattle are homeotherms, meaning that they maintain a nearly constant inner body temperature that ranges from 38 to 39.3°C. Generally, dairy cattle have higher temperatures than their surroundings. Their normal body temperature is sustained by striking a balance between heat production and heat loss to the environment. The control of body temperature is under the influence of the hypothalamus gland, which triggers various mechanisms to neutralize high or low temperatures. For instance, low temperatures are countered by the heightened transformation of feed to heat energy. Conversely, high body temperatures are counteracted by high respiration rates, increased blood flow to the skin, ruffling up of fur, and adjusting the rate of evaporation from the lungs and skin. Excess heat is conducted to the surface of the skin, through which it is emitted to the environment via processes such as conduction, convection, and radiation.
Temperature fluctuations also alter the behavior of dairy cattle. For example, there is reduced activity when the temperatures are high. Furthermore, when the feed that is consumed is transformed into milk, heat is liberated as a by-product. Therefore, high-yielding animals are more susceptible to heat stress than low-yielding ones when exposed to high temperatures. Very young animals do not have fully developed mechanisms for regulating body temperature, especially the capacity to augment heat production through metabolic activities. Therefore, they need to be kept at higher temperatures than older animals. An implication of these processes with respect to the housing of dairy cattle is that heat and moisture generated by animals restrained in a structure should be eliminated by aeration. Consequently, the use of open-sided structures is common in the tropics to permit adequate ventilation. Nonetheless, if enclosed buildings are used to house dairy animals, there is a need to provide several vents for sufficient aeration.
The genetic composition of dairy cattle also affects this parameter. For instance, European cattle achieve optimal milk production at high humidity and temperatures in the range of 4 to 24°C.[2] Low temperatures do not affect their products as long as the fluctuations are minimal. However, when the temperatures increase to more than 25°C, milk production begins to decline. The rate of decline is proportional to the increase in temperature and maybe as high as 50% when temperatures reach 32°C. Conversely, Zebu cattle that are indigenous to warm areas can withstand temperatures in the range of 15 to 27°C. A significant reduction in milk production is only observed once the temperatures exceed 35°C.
Modern animal housing and management systems in dairy farming
Structural advancements in dairy farming have led to the development of novel barn systems, increased herd sizes, and reduced grazing for dairy cows. Furthermore, advances in breeding have led to the development of genetically modified breeds with large body sizes. However, even with these changes, climatic conditions, especially humidity, temperature, rainfall, wind, and snow, affect the construction of animal housing. Dairy farmers also strive to keep their animals in clean, dry, spacious, and comfortable units. Therefore, these factors may necessitate modifications of housing units of conventional structures. Studies have been done to determine the impact of grazing on integument changes and animal wellbeing under varying conditions. These factors need to be considered in confined dairy animals as well.
When designing a housing unit for dairy animals, the first step involves establishing a management plan that is informed by the principles of good dairy management. The plan should consider the different groups of dairy animals as well as handling and feeding arrangements. The farmer should also consider possible room for expansion in light of herd size increase.
The dairy cattle housing system
Housing for intensive dairy farming serves the three main purposes of confining the animals, easing herd management, and safeguarding the cattle from extreme climatic conditions. Three types of housing are possible based on the prevailing temperatures and climatic conditions. These include open-air corral, roofed open free stall, and enclosed free-stall barn systems for tropical, Mediterranean and arid, and cold, temperate climates, respectively. When rearing dairy cattle in temperate and colder climates, the best level of protection is provided by enclosed free-stall barns. These housing units need to have good ventilation and protection from wind. Conversely, windbreaks should be situated on the side of the barn. Interspaces should be provided to permit the free circulation of air. When building barns in semi-arid climates, dairy cows should have rows of covered free stalls to provide protective cover. On the other hand, barns in hot climates need to have evaporative cooling without free stalls to protect the animals from high temperatures and rain.
In addition, farmers should focus on allowing ease of movement for logistics during day-to-day operations. For example, cattle should be allowed to move freely from the resting area to the milking parlors without having to pass through the feed lanes. The farmer should be able to feed, milk, remove manure or put different groups of animals in the milking parlor without getting in the way of other cows. Furthermore, ease of movement prevents injuries such as bruises and cuts to the animals’ integumentary system, which can increase susceptibility to infections. The animal housing unit should also have different holding spaces for various groups of animals. For example, calves should be separated from adult cows.
Advancements in the enclosed free-stall barns
When building enclosed free stalls for dairy animals, farmers ought to provide optimal resting places to safeguard the integrity of the integumentary system. For instance, there should be adequate space for the animal to get up and lie down easily. It is estimated that an averagely-sized dairy animal will swing forward approximately 60 to 70 centimeters while shifting most of its weight frontward to facilitate the raising of the hind region. For this movement to be performed, there should be adequate space for the animal to push its head forward. Failure to provide this space hampers the rising of the hind legs. Furthermore, excessive restriction compels the animal to rise on its front limbs, which increases the likelihood of damage to the udder or the delicate skin that is found around this area. Inadequate space also increases the risk of leg injuries. [3]
For these reasons, housing for dairy cattle should be designed appropriately by a qualified animal specialist. Contemporary animal sheds provide adequate resting space that permits a higher level of free motion. As much as partitions are necessary to ease operations, they should not become obstacles to the animal. Consequently, the front end of the stall can be left open to provide enough space.
Conclusion
Creating an ideal environment is the surest way to harness the potential of dairy animals whose milk production is affected by a blend of physiological and physical conditions. The integument plays a vital role in determining the response of dairy cattle to environmental conditions, which also affects the health of the animals. Therefore, dairy farmers need to understand its function and use it to balance the feeding, housing, and general care of dairy cattle.
Reference List
Bewley, J.M., L.M. Robertson, and E.A. Eckelkamp, ‘A 100-Year Review: Lactating Dairy Cattle Housing Management’, Journal of Dairy Science, vol. 100, no. 12, 2017, pp. 10418-10431.
Food and Agriculture Organisation,Animal Environments Requirements, [Website], 2017, Web.
Starr C. et al., Volume 5 – Animal Structure and Function, 14th edn, Boston, MA, Cengage Learning, 2015.
Foonotes
- C. Starr et al., Volume 5 – Animal Structure and Function, 14th edn, Boston, MA, Cengage Learning, 2015, p. 528.
- Food and Agriculture Organisation, Animal Environments Requirements, [Website], 2017, Web.
- J.M., Bewley, L.M. Robertson, and E.A. Eckelkamp, ‘A 100-Year Review: Lactating Dairy Cattle Housing Management’, Journal of Dairy Science, vol. 100, no. 12, 2017, p. 10420.