Feeding Newborn Calves to Thrive in Cold Weather

Mrs. Dianne Shoemaker, Extension Dairy Specialist, OSU Extension Center at Wooster (top of page)

The average temperature across northern Ohio last year was slightly more than 50°F.  If the average temperature was the usual temperature, we would usually have decent conditions for raising neonatal calves.  The lower critical temperature for calves from birth to 7 days of age is 55°F.  In other words, calves do not require extra nutrients for maintenance until the temperature drops below 55° F assuming they are housed in a clean, dry, draft-free environment.  Maintenance means the calves neither gain nor loose weight with all body systems functioning properly while maintaining a normal body temperature.

Between 7 and 30 days of age, calves can stand a little more cold stress before needing to consume extra nutrients to meet maintenance requirements, with the lower critical temperature in the 46° to 50°F range.  After 30 days of age, the lower critical temperature drops to ~44°F.

As all calf feeders and anyone else who works outside on an Ohio dairy farm in winter knows, temperatures do not typically average 50°.  Looking at the National Weather Service’s Climate Graphs for northern Ohio, Mansfield’s weather was fairly representative of conditions across the state with Toledo averaging a degree higher and Youngstown a degree lower. 

In 2006, the average daily temperature was 32° F or less from mid-December thru February.  Daily lows continued to dip below 32° F regularly thru mid April.  To compound feeding challenges, temperatures fluctuated widely within that time period, with temperatures between January and March fluctuating from -8° F in February to 71° F a month later.

Maintenance Requirements for Neonatal Calves

So, how do we need to adjust nutrition for calves less than 3 weeks old in cold weather?   Using the National Research Council (Nutrient Requirements of Dairy Cattle, 7th rev. ed., 2001. Versions 1.0 computer program, 2000), let’s look at maintenance requirements first.  With a 90 lb calf (Holstein heifer) and a 60 lb calf (Jersey heifer) as examples, we can see that a critical need for additional nutrition occurs as temperatures drop toward freezing (Table 1).

Table 1. 20:20 milk replacer dry matter (DM) needed to meet maintenance requirements for newborn calves.

Traditional industry milk replacer feeding recommendations are to feed large breed calves 1.0 lb of milk replacer powder split between two feedings per day (hence, the 8 ounce “cup”).   When the weather is warm, that rate of feeding not only meets the 90 lb calf’s maintenance requirements but will also allow her to gain 0.5 lb/day of body weight. 

However, as soon as the temperature drops, maintenance nutrient needs change dramatically.  Between 60° and 32° F, both calves need 50% more milk replacer (DM basis) to simply meet maintenance requirements.  Additional milk replacer must be fed beyond that if we expect the calf to grow.  While the most dramatic change occurs in that first drop of almost 30° F, maintenance demands continue to increase as the temperature continues to drop.

During the first few weeks of life, nearly all of the calf’s nutrients come from their liquid diet, whether it comes from fresh milk, milk replacer, or a combination of the two.  While we encourage starter consumption, it will not provide significant nutrients for the very young calves.  Therefore, we will evaluate only milk-based diets in the following discussion.

Several factors are critical for newborn calves to thrive.  An easy delivery in a clean, dry environment; quick feeding of enough quality colostrum leading to a successful transfer of passive immunity; and clean, dry and draft-free housing are just a few.  Whether those factors were all met, or if the calf was stressed in some way, adequate nutrition will help her to maintain body condition and grow into a healthy calf that is able to fight off multiple challenges.

How Must Nutrition Change in Cold Weather?

Quite simply, the calf has to eat more.  If she isn’t offered the nutrients, she simply won’t get them.  If she doesn’t get enough nutrients, she will not grow in a “best case” scenario.  More likely, if the deficiency lasts for any period of time, she will loose weight and her ability to fight off additional weather and disease challenges declines.

How much more milk or milk replacer these calves need is a function of temperature and our target rates of gain.  Tables 2 through 4 illustrate DM requirements for our 60 and 90 lb calves receiving a 20:20 MR diet:

Table 2. Pounds of 20:20 milk replacer dry matter needed for maintenance and gain for a 90 lb heifer calf at declining temperatures.

¹Maintenance diet.

Table 3.  Pounds of 20:20 milk replacer dry matter needed for maintenance and gain for a 60 lb heifer calf at declining temperatures.¹

¹Maintenance diet.

Occasionally you will see the same amount of milk replacer supporting the same amount of growth at more than one temperature.  In Table 3, this happens more than once.  The given diet provides a finite amount of energy and protein available for growth once maintenance requirements are met.  If protein is the limiting nutrient for growth, excess energy in the diet is stored as fat.  Beyond an adequate body condition, we do not want to raise calves that are growing fat.  We want them to add non-fat muscle, bones, etc.  In the case of the 60 lb calf, if we desire a 1.0 lb/day rate of gain, the 1.6 lb of 20:20 milk replacer DM requirement provides enough protein for that level of gain.  However, there is excess energy available which is sufficient to meeting increasing demands for energy to maintain the body during increasing cold stress until the temperature drops to 5° F where that diet is very well balanced.  In other diets, energy is the limiting nutrient, and excess protein fed will be excreted by the calf.

Some farms feed fresh milk and may or may not pasteurize the milk.  The exact composition of this milk will vary from day to day and farm to farm.  The NRC program used to generate these tables provided fresh milk values of 3.175% protein and 3.85% fat.  In milk with 12.5% solids, this would be equivalent to a 25:31 milk replacer analysis.  Table 4 shows the milk dry matter maintenance and gain requirements for our 90 lb calf fed fresh milk.

Table 4.  Pounds of 25:31 whole milk DM (3.175% protein and 3.85% fat) needed for maintenance and gain for a 90 lb heifer calf at declining temperatures.

¹Maintenance diet.

Assuming that a typical calf bottle holds approximately half a gallon of liquid and if it is filled with fresh milk, it would deliver about a half pound of dry matter to the calf.  On a per volume basis, the fresh milk at 25:31 provides more nutrients to our calf than a 20:20 milk replacer.

As temperatures spend more time near and below freezing, nutrition programs must be adjusted to provide calves nutrients for both maintenance and gain.  While it is tempting to short the calves on milk or milk replacer dry matter to “force” them to eat starter and/or “save” money on milk replacer, calves less than three weeks old will start to eat grain, but will they either not gain or loose weight if underfed milk.  Calves raised in those conditions will not have nearly the ability to deal with cold stress and fight off disease challenges that properly fed calves will.

How Should Additional Milk be Fed to Calves?

Healthy calves can easily eat more than the typical bottle or half gallon of milk or milk replacer fed at 12.5% DM per feeding. Actually, they would like to eat more than that.  Large calves can and will eat a gallon per feeding.  Small breed calves can handle a half to ¾ of a gallon with no adverse effects.  If they have eaten most of their diet, but do not care to finish, do not force feed an otherwise healthy calf.

Calves are designed to handle 12.5% DM liquid diets (equivalent to fresh milk).  Keeping diets close to this concentration is less likely to cause digestive issues than trying to concentrate more powder in a given volume of water.  There is some suspicion that concentrated DM in liquid diets can contribute to the incidence of acute bloat syndrome, an infrequent, but usually fatal disease in neonatal calves.

Additional liquid intake will result in loose manure which should not be mistaken for scours.  While calves can still contract scours when their manure is simply loose from a higher liquid intake, they will maintain a good appetite.

Feeding calves to gain does not decrease the need for good housing; clean, dry, fluffy bedding that calves can nestle down in; and top-quality care.  Invest time and adequate nutrition in these calves.  They are the future of your dairy farm business.