Thursday, October 11, 2018

Why Would Milk Feeding Method for Calves
be Related to Rate of Growth?

In a US national study of dairy heifer growing practices we find these facts:

                                                    Calves by Average Daily Gain(%)
Feeding method               Poor (<1.4#/da)   Fair (1.4-1.8#/da)   Excellent (>1.8#/da) Total

Bucket/ pail only                     23                       37                           40                            100%
Bottle & Bucket                      32                       35                           33                             100%
Bottle only                              42                       36                           22                             100%

To put the rate of gain in perspective let's add that in order to double birth weight in 8 weeks (56 days) a 90# calf needs to gain 1.6 pounds a day. If her average gain is 1.8 pounds a day for 56 day she will gain a total of 101 pounds - that is really good growth.

So, why is the percent "Poor" so much higher for bottle feeding compared to the other two methods?

This research was not set up to answer this question. Let's do some guessing.

Many of my clients that feed with buckets have "step-up" milk feeding programs. They start calves at 4 quarts a day (divided into 2 feedings). As soon as practical they ramp up milk volume with a goal of being at 8 quarts a day by 10 15 days of age. Most of these operations also have a "step-down" weaning process rather than just quit milk feeding "cold-turkey."

What happens with bottle feeding? Well, the traditional milk feeding bottle has a 2 quart capacity. The calves get fed a bottle twice a day. That sets an upper limit of 4 quarts a day. What are the chances that these calves will be in the "poor" (<1.4#/da gain) category? I am guessing the odds are pretty high - especially if freezing temperatures prevail during the milk feeding period.

I am guessing that the equation "dry matter intake drives growth" applies here. Bucket feeding provides the flexibility to easily increase volume of milk fed well above 4 quarts a day. Few calf operations have the ability to feed with 2 and 3 and 4 quart bottles as the calf grows from birth to weaning.

By the way, season of the year [environmental temperature] was associated with rates of gain - hotter weather depressing gains, cooler weather showing higher gains. In calf hutches, during freezing weather with my intensive-fed calves average daily gain was usually between 1.9-2.1#/day. During the hottest summer months our average daily gain was usually between 1.6-1.8#/day.

My experience with using both bottles and buckets:

I fed my calves with both bottles and buckets. Bottle fed for about the first 4-5 days (until nursing strongly). Switch to bucket - lots of wet clothing and spilled milk along here - I had one Brown Swiss calf that never did drink out of bucket.

Ramp up milk replacer (15% solids, 28-20) volume to match appetite with the goal of 4 quarts twice daily. At 5 weeks any calf eating one pound  (454g) of calf starter grain (20% protein) every day lost her PM milk replacer feeding - she had to "starve" on only 4 quarts (3.8L) a day.

Most of these calves were consuming more than 4 (1.8kg) pounds of grain daily by the time they were 7 weeks old. Somewhere between 45 and 49 days they began receiving a small "handful" of hay in their grain bucket three times a week. Most were full weaned around 50-52 days. Moved to group pen (5 to a pen) around 60 to 65 day (depended a lot on pressure for empty hutches).

Reference: Shivley, C. B. and Others, " Preweaned heifer management on US dairy operations: Part 6. Factors associated with average daily gain in preweaned dairy heifer calves." Journal of Dairy Science 101, 9245-9258. October 2018

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