Introduction
There are many housing options for young, preweaned calves – hutches, barns (heated and unheated), greenhouses, etc. There are many bedding options, as well, including shavings, straw, sand, etc. The value of these various management options will depend on the location of the farm, environmental temperature, prevailing winds, solar radiation and needs for labor efficiency and disease control. One 2004 study compared several types of bedding on calf health and growth. Calf Note #111 (https://www.calfnotes.com/pdffiles/CN111.pdf) is available and summarized some of the results of that study.
Individual housing for preweaned calves has been shown to reduce the risk of disease and death loss. In places where the temperature drops below freezing, there are several management strategies that producers can employ to maintain the welfare, growth and health of calves. For example, supplemental heat can maintain a more comfortable environmental temperature for calves. However, several research studies have shown that supplemental heat can also maintain temperatures conducive to microbial growth, thereby increasing the risk of disease.
Trial 1
In the first trial, 48 calves were assigned randomly to receive one CMR (26% CP, 17% fat) at various amounts (see Table 2) to weaning at 42 days. Calves were housed in individual pens, half of which were bedded with hardwood shavings and the other half with wheat straw. Calf starter and water were available at all times. The researchers measured intakes, growth rates, fecal scores and feed efficiency to d 56.
These data suggest that calves housed on straw in this barn utilized ingested energy and protein more efficiently than calves housed on shavings. This makes sense, as straw provides additional insulation to calves compared to straw and other bedding types. The average environmental temperatures in this trial were -5 and -9ºC during d 0-21 and 22-42, respectively. This value is generally below the lower critical temperature for milk-fed calves; therefore, these calves would be expected to be using additional energy to maintain their body temperature. Therefore, this trial showed that the difference in bedding type and insulation provided by that bedding can be measured in improved performance under certain conditions.
Trial 2
Overall
The authors reported that bedding calves with wheat straw versus shavings increased body weight gain by 5 to 12%. This is an impressive rate of increase in growth. It does, of course, depend on the conditions of the experiment. This study was conducted in Ohio in the winter and temperatures were often below freezing (see Table 1). This is an important consideration if your operation is in a location with temperatures that differ markedly from those in Table 1.
An important take home message from these studies is that housing and bedding are critical to the comfort, health and performance of calves. Wheat straw, which carries greater insulative capacity compared to hardwood shavings, allowed the calves to better maintain body heat, thereby improving performance. It’s interesting that efficiency of feed utilization was not markedly improved, although G:F was improved on d 0-21 in trial 1. Improved feed efficiency which would suggest that less energy was being used for heat production. Further research would be necessary to understand this apparent discrepancy.
The value of straw versus shavings may differ in other times of the year. As pointed out in Calf Note #25 (https://www.calfnotes.com/pdffiles/CN025.pdf), using straw as bedding during summer months can dramatically increase fly populations compared to other bedding options, which can make straw less desirable during those periods of the year.
Summary
These interesting trials conducted by Hill and coworkers shows clearly that simple management practices such as bedding calves with straw can have a positive impact on intake and growth of calves that are housed in cold, naturally ventilated barns and exposed to low environmental temperatures. It’s important to keep in mind all these aspects of calf housing management to ensure happy, healthy calves.
References
Hill, T. M, H. G. Bateman II, J. M. Aldrich, and R. L. Schlotterbeck. 2007. Effects of Feeding Rate of Milk Replacers and Bedding Material for Calves in a Cold, Naturally Ventilated Nursery. The Professional Animal Scientist 23:656–664.