Thursday, October 30, 2014

How Long Does It Take for Colostrum to Move Out of the Rumen?

This was the question I was asked last evening at a calf raisers' meeting. "If I feed a calf her colostrum with an esophageal tube feeder how long does it take for the colostrum to move out of the rumen into the abomasum?"

In 1978 a research project looked at stomach tubing calves (A. Molla, "Immunoglobulin levels in calves fed colostrum by stomach tube." Vet Record 103:377-380). Colostrum was fed at the rate of 81ml/kg live weight or about 3.4 quarts for a 90 pound calf. The report states that colostrum moved "efficiently" from rumen to abomasum. Bottle-fed and tube-fed calves achieve similar levels of immunoglobulins in their blood. Although this suggests fairly rapid emptying of the rumen the author did not specify a definite time.

Subsequently, Hopkins and Quigley (B.A. Hopkins and J. D. Quigley III, "Effects of methods of colostrum feeding and colostrum supplementation on concentrations of immunoglobulin G in the serum of neonatal calves." Journal of Dairy Science 80:979-983, 1997) compared nipple-fed calves with those fed with a stomach tube. All the calves were offered 4 quarts of colostrum; some of them were nipple-fed only and others were stomach  tubed. As part of their methodology they determined emptying rates for the rumen. They reported a 3-hour rate for the total volume of colostrum fed to move from the rumen into the abomasum.

Both of these studies fed greater than 3 quarts of colostrum.

What about smaller volumes? Two studies that fed variable amounts of colostrum (that is, 1.6 and 3.2 quarts) showed that when the smaller volume was fed with a stomach tube the delay in rumen emptying significantly depressed IgG levels in the calves.

Click HERE to read the November 2009 issue of Calving Ease newsletter, "Using a tube feeder: yes or no." The results of the two studies with different methods are shown. Enjoy. 

Wednesday, October 29, 2014

Where Does the Energy Come From
To Dry Off A Calf?

I think we all can agree that when born calves are wet. 

I think we all can agree that dams usually do an acceptable job of cleaning up calves and getting rid of a lot of the birth fluids. One way or another the hair coat of the calf gets dry enough so that the hair stands on end - I call that "fluff dry." Regardless what one calls this state we do know that the rate of heat loss is substantially lower compared to a wet, matted hair coat.

Now, the question is, "Where does the energy come from to complete the job of drying off the calf?" and "Why does this make a difference?"

Under warm and dry environmental conditions much of the "drying off" takes place without drawing heavily on the energy supplies of the calf.

Under cold and damp environmental conditions much of the "drying off" takes place by the transfer of heat from the calf's body to her body surfaces/wet hair coat.

Does this energy drain on the newborn calf make a difference for her subsequent well-being? I claim that using this energy (probably from the brown fat supply with which she was born) in order to get dry should be the subject of our management decision-making.

On my balance sheet I think it is a cost-effective decision to manually dry calves in cold, damp weather rather than put them at increased risk of either death or illness in the subsequent days as a neonate.

For methods and ideas for drying calves click HERE. You will find the Calving Ease newsletter issue devoted to practical tips for manually drying calves. Enjoy.

Tuesday, October 28, 2014

Use Caution When Reading Research Results

Yet again I came across research results that come from a study design that has at least one major flaw. 

Calves were assigned to either a control group or one of four treatments. On one hand, since the calves were born over six days the group assignment made sure calves in each group represented the same profile of birth dates. 

On the other hand, no mention was made of making each group equally representative by either birth weight or immunity status (i.e., blood serum total protein levels). Just saying, "... and randomly assigned to one of five treatments," in my mind leaves too much possible bias in group populations given that they were measuring health and rate of growth of the calves in response to the experimental treatment.

Thus, when presented with study results I recommend asking about the methods used to assign the calves to the various treatments in the research.

Friday, October 24, 2014

Another Note on Cross-Sucking

In addition to the Calving Ease newsletter on cross-sucking (September, 2013 or click Here) data from a New Zealand study suggest another tool to use when trying to suppress this problem.[Margerison and Others, "The effect of solid feed diet on the oral and cross-sucking behavior of pre-weaned dairy calves." Journal of Dairy Science E-Suppl 1, #615]

They compared feeding solid rations to preweaned calves of low forage alfalfa TMR (LF), higher forage alfalfa TMR (HF) or perennial rye grass hay with a pelleted starter (HPS). Calves were followed out to 12 weeks of age.

Cross-sucking was highest for the low forage ration, intermediate for the higher forage ration and lowest for the grass hay/pelleted starter ration. The authors conclude, "While cross-sucking was not entirely eliminated, providing perennial ryegrass hay along with a pelleted starter resulted in the least non-nutritive sucking behavior."

Thus,we have another tool in group housing - providing a limited amount of palatable hay - not so much as to suppress calf starter grain consumption (remember how small the rumen is at the pre-weaned stage) but enough to promote lots of cud chewing.

By the way, the grass hay/pellet ration calves had the highest dry matter intakes (3.7 pounds/day compared to 1.8 pounds/day for low forage TMR and 2 pounds/day for high forage TMR). Since dry matter intake drives growth these grass hay/pellet ration calves had the highest rate of gain.

Tuesday, October 21, 2014

Post-Weaning Digestion Impaired Among
Intensive-Fed Rapidly Weaned Calves

We have suspected from field observations that intensive-fed preweaned calves have problems digesting solid feeds in the early post-weaning period.

In an abstract entitled, "Performance of and digestion in calves fed conventional, moderate, and aggressive milk replacer programs," [Hill and Others, J.Dairy Sci Vol 97, E-Suppl 1, #613] results are reported for intensively-fed calves that received 2 pounds of milk replacer daily. These calves were compared to those fed 1 lb. and 1.5 lb. of powder daily. Thus, there were three treatment groups.

The intensive-fed calves were fed the full ration of powder up to 49 days. In contrast the calves receiving the lower amounts of powder until 42 days. The method of weaning is not described - perhaps it was done by abruptly in one day.

Not surprisingly, the calves fed less milk replacer powder ate more calf starter grain than the intensively-fed calves. Though not included in the brief abstract we can almost be certain that the calves fed less milk replacer powder began regularly consuming grain earlier in life than the calves receiving more powder. These facts would lead us to the conclusion that the levels of rumen development would vary with the highest level being among the calves that began to consume grain earliest in life and among the calves that consumed the largest volume of grain. 

NDF digestibility was analyzed on fecal samples collected on days 51-55 on trial from calves in all three treatment groups. The values reported were:
Lowest milk replacer group = 54%
Middle milk replacer group = 51%
Highest milk replacer group = 26%

Thus, what we have seen on farms is documented. Intensive-fed calves that are not weaned with enough time to let their rumen maturation reach the "mature enough to feed me" level are at a severe disadvantage. 

These data showing a NDF digestibility level of only one-half of the other calves reinforce the need to carefully plan a "step-down" weaning program for intensively-fed calves.

Friday, October 17, 2014

Collect Colostrum Sooner rather than Later

Have you heard this one?

"If I wait to collect colostrum from my fresh cows I will get more colostrum."

Sorry, life does not work that way. Recent research reported in the article entitled, "Milk production during the colostral period is not related to the later lactational performance in dairy cows" (Kessler, E. C. and Others, Journal of Dairy Science 97:2186-2192, April 2014), showed no relationship between the interval between calving and the volume of colostrum collected at first milking for both heifers and cows.

Waiting to collect colostrum is not an effective method to increase the volume of colostrum at the first milking.

But, there is a strong negative outcome of waiting for this first milking. Morin and Others reported that the longer one waits to collect colostrum after calving the lower the concentration of antibodies in the colostrum. Compared to milking a dam within 2 hours after calving, the antibody losses in colostrum were reported to be 17% at 6 hours post calving, 27% at 10 hours post calving and 33% at 14 hours post calving. 

Collect colostrum sooner rather than later in order to harvest the highest quality colostrum from your fresh animals. 

Wednesday, October 15, 2014

Early Identification of Pneumonia Calves

It seems to be pretty well accepted that early identification and treatment of calves with pneumonia is a best management practice.

The guide developed by Sheila McGuirk (Univ. Wisconsin College of Vet. Med) has been very useful for me. See THIS link to find that guide for observing individual calves. 

When observing calves in individual pens or hutches I just assign one row on a ruled tablet to each calf. As I look at the calf I mark down her nasal and eye score as well as a scour score. After I finish walking all the calves I make a crude summary at the bottom of the last page counting up scores for all calves. That is, how many 0's, 1's, 2's and 3's for the whole population.

Today I found the group observation sheet at this site. Click HERE for this sheet. That way one can summarize scores with one row per pen. Dr. McGuirk suggests counting the number of abnormal scours (2's and 3's) for each of four observation points. She suggests the goal of less than 25% abnormal scores on any point. 

These scoring guides have been helpful in my consulting work as a way to teach the calf care personnel to observe calves. Each time a person visits the individual pen or hutch they have the opportunity to spot abnormal eye or nasal discharge. Bedding is a good time to observe for the calves as they are active jumping around - which ones are coughing?