Poor cattle performance can be attributed more to muddy conditions, harsh wind and wet resting areas than to low air temperature. All animal types and sizes must have adequate wind protection. Natural bush offers good protection. Properly designed windbreak fences and open front sheds supply adequate protection but involve a cost.
Wind Breaks and Mounds
Windbeaks are very beneficial to helping reduce windchill on cattle. Recommended spacing between planks is 20% – 25% of plank width. Plank width greater than 10 inches is less effective. Openings over 2 inches wide are not recommended as too much wind can pass through in one place. Slotted wind break fences should be 10 feet tall for better wind and snow control. For animals over 600 pounds windbreak fencing and dry resting areas are usually sufficient.
Elevated, bedded resting areas are very effective for keeping cattle clean and dry. Bedded mounds should be set away from feeding and watering areas. Make the mounds rectangular shaped. Place mounds so they do not interfere with good pen drainage. A well-compacted soil base material is essential. The top should be rounded with a minimum height of 5 feet at the center. Side slopes must be flat enough that cattle can easily walk to the top of the mound. Maximum side slopes of 1:4 are recommended.
Bedded area requirement should ensure that the manure pack continues to generate heat during winter. A 12 to 18 inch deep manure pack built up before December will establish a heat source that will continue through the winter
A shelter’s main purpose is to protect cattle from cold wind, drifting snow, rain and extremely high or low temperature. Natural shelter available and cattle hardiness determine the amount of additional shelter required. Holstein cattle have thinner skin and less hair than beef cattle and will require more protection. All sheds should be open to the south, if possible. The greater the depth of the shed, the better the wind protection for the cattle.
Unheated livestock buildings should not be totally enclosed. Total enclosure allows too much moisture buildup and creates an unhealthy environment for cattle. High humidity is a contributing factor to pneumonia and other diseases. Unheated sheds require good natural ventilation to reduce condensation and frost buildup. The open side of shelters should be away from prevailing winter winds and preferably south facing. Air intake and exhaust openings should be provided. The air exhaust slot in the peak of a truss rafter shed should be 1 inch wide for each 10 feet of building width, with a minimum width of 4 inch. The exhaust slot should extend the length of the peak except for 8 feet at each end. The amount of rain or snow that can enter through this slot is insignificant.
Environmental Cold Stress
Adjustments to energy intake must be made to cope with winter conditions. A practical rule of thumb is to increase energy intake by 1% for each degree of coldness below the lower critical temperature of the cattle. For practical purposes, a 20 ºF temperature can be used as the lower critical temperature. Thus, if outside temperature is 00 ºF with calm wind speed, then energy intake should be increased 20%.
Besides the poorer performance when cattle have cold and wet conditions dressing percentages can be improved by reducing mud and manure from the hides before market. In a study reported in a feedlot conference in Iowa the following chart was presented.
Impact of mud scores on dressing percent
Mud Scores are defined as:
- 1 = no tag, clean hide
- 2 = small lumps of manure attached to the hide in limited areas of the legs and underbelly
- 3 = small and large lumps of manure attached to the hide covering larger areas of the legs, side and underbelly
- 4 = small and large lumps of manure attached to the hide in even larger areas along the hind quarter, stomach and front shoulder
- 5 = lumps of manure attached to the hide continuously on the underbelly and side of the animal from brisket to rear quarter
Take Home Messages
- Livestock that are provided a clean and dry area out of the wind during extreme winter weatherhave a lower energy requirement.
- Critical temperature for beef cattle with a heavy winter coat is 20 ºF.
- Increase energy intake 1% for every degree of coldness below the lower critical temperature of cattle that are not on a high energy diet already.
- Proper ventilation will reduce health problems
- Reduce mud and manure on hides will increase dressing percentage and price of cattle
Source: Zen Miller, UW Extension Ag Agent