Effect on Live Weight of

Transition Rations: Limited Hay vs. Ad Lib. Hay

I spent time last week using the NRC 2001 calf growth simulation software looking at the question of how calves coming off an intensive milk replacer feeding program would respond to two transition rations. Based on my field experience over the past decade or so I made some assumptions about how calves respond to weaning and pen moves. And, I estimated intakes of both grain and hay from the period of 35 to 82 days of age. The data for the graph are NOT from a research project. They come from my personal field observations.

If you click Here you can see the graph showing estimates of live weight with two transition rations in the group pens:

 

(1) Limited-Hay ration with Week 1 = no change from individual pen, ad lib grower grain and water; Week 2 = add 1 pound hay per day per calf; Week 2 = add 2 pounds hay per day per calf; Week 3 = Ad Lib. grain, water and hay.

(2) Ad Lib. Hay ration with Week 1 = Ad Lib. hay, grower grain and water; Weeks 2 and 3 = same as week 2. 

 

 

Too Much Hay Too Quickly

 

Again I visited a dairy with self-reported "issues" with transition heifers. The calves were raised from birth to weaning in individual pens. With the intensive milk replacer feeding program calves were gaining well. At 42 days the milk replacer ration was cut in half with ad lib. water and calf starter grain. At 49 days all milk feeding was stopped and at 56 days the calves were moved into group pens.

 

The group pen ration was ad lib. calf grower grain, water and a palatable hay. Calves loved the hay and grain consumption dropped drastically. Within a week calves were starting to look rough and some of them had to be treated for pneumonia.

 

After coming back to the vet clinic I spent time using the NRC 2001 calf growth simulation software trying to dig into this nutritional puzzle. Based on my field experience over the past decade or so I made some assumptions about how calves respond to weaning and pen moves. And, I estimated intakes of both grain and hay from the period of 35 to 82 days of age.

If you click Here you can see the graph showing estimates of daily gain with two transition rations in the group pens:

(1) Limited-Hay ration with Week 1 = no change from individual pen, ad lib grower grain and water; Week 2 = add 1 pound hay per day per calf; Week 2 = add 2 pounds hay per day per calf; Week 3 = Ad Lib. grain, water and hay.

(2) Ad Lib. Hay ration with Week 1 = Ad Lib. hay, grower grain and water; Weeks 2 and 3 = same as week 2. 

The data for the graph are NOT from a research project. They come from my personal field observations.

The "Ad Lib. Hay" line (should be red on your screen) reflects pretty much what I saw on this dairy - the calves stood still (that is, no growth) after the move into the group pen and ration change. After about three weeks (around day 76) the heifers seemed to turn around and were looking good again.

Too much hay to quickly. A more gradual introduction of hay combined with the ad lib. grower grain allowed calves to continue to grow while their rumen "bugs" adjusted to the new feed.

Colostrum and Coliform Bacteria

 

I finally took time to go back into the Journal of Dairy Science to find the research report on "Influence of Colostrum on Transepithelial Movement of Escherichia coli 055."  (L.D. Corley, T.E. Stanley, L.J. Bush and  E.W. Jones; Journal of Dairy Science 60:1416-1421, 1977

 

The question? How does the presence of colostrum influence the way E. coli attach to the cells in a newborn calf's gut?

 

3 treatments - fluids given to colostrum-deprived calves 2 to 6 hours hold.

T1. E. coli  given in saline.

T2. E. coli suspended in colostrum.

T3. E. coli given in saline 1 hour after a colostrum feeding.

Results:

T1. Numerous E. coli found in the gut tissue, especially in lymph nodes.

T2. E. coli found in lymph nodes but in lower numbers than first treatment.

T3. No E. coli found in lymph nodes in the treatment where colostrum was fed before exposure to the coliform bacteria.

Moral of the Story

Adult cow feces that get into the mouths of calves before they are fed colostrum (like Treatment #1) can result in significant colonization of the gut.

Best case is plenty of high quality CLEAN colostrum as soon after birth as possible.

Insights that Come from Walking in Calf Barns

 

Dr. Mark Thomas, Dairy Health Management, made a presentation on group housing at the Discover conference last week. He has walked in quite a number of preweaned group pens the past couple of years. His insight was that when calves are fed ad lib. or free-choice milk or milk replacer (or rates of 8 liters or more a day with an automatic computer feeder) the pens require much more bedding than calves fed on more restricted milk rations. Rationale? More liquid in results in lots more urine out!

 

So, if you have group pens for preweaned calves that are on an intensive milk/milk replacer feeding program be aware that these pens will require more than the usual amount of bedding in order to keep the calves dry.

 

Second insight. Dr. Ken Nordland , University of Wisconsin, made a presentation on ventilation of calf barns. In the course of his work on this subject he is in many calf barns. Sometimes he observes bedding procedures that fill the barn with dust - either from chopped straw or sawdust. When asked about problems that might result from exposure to this kind of organic particulates he explained that the endotoxins attached to bacteria cell surfaces (these are part of the "dust") are highly inflammatory. This exposure, therefore, often leads to significant imbalances between pro- and anti-inflammatory responses in calves - this leads to supression of immunological defenses.

 

So, if your bedding procedures are regularly exposing calves to these kinds of organic "dust" and you have an issue with treating too many calves for pneumonia maybe it is time to think about some other way to get bedding into the calf pens. 

 

Insights that are food for thought.

The Great Grain Divide

 

Talk to heifer growers (contract or dairy farmers) and they have plenty of opinions. One of these is about the form of the grains fed post-weaning. At one point are the "Textured" folks; at another point are the "Pellet" folks; and at a third and final point are the "Shelled Corn" folks.

 

They all believe the other two kind of starter grain feeding is not nearly as good as theirs. "Calves will eat more of my grain" or "Calves find my grain more palatable."

 

At the recent Discover conference (May 28-31) a University of Minnesota researcher, Hugh Chester-Jones, reviewed results comparing intakes of 4 rations that represent two of the options above. 

The rations were (free-choice or ad lib. access):

1. 18% crude protein (cp) texturize grain mix  without hay

2. 18% cp texturized grain mix  with hay

3. 16% cp protein whole corn with pellet grain mix without hay

4. 16% cp protein whole corn with pellet grain mix with hay

Guess what?

All four of the rations were consumed by the heifers at the same rate over the first 14 days in the transition pens. Intakes peaked around 10 days at approximately 6 pounds per head per day.

I noted an interesting little blip in the data. Have you ever had the feeling that grain intakes drop off for a few days when calves are moved from individual to group pens? 

Heifers on all four rations dropped from about 6 pounds per head daily to an average of just under 4 1/2 pounds per day. That is a 27 percent drop! 

The heifers took 5 days to come back up to the "pre-move" intake levels. 

So, I concluded that compared to these research results the drop in grain intakes of my heifers at Noblehurst Farm were quite normal - the drop and rebound behavior was not the result of anything I was doing wrong. [By the way, over 12 years I was never able to prevent this temporary dip in grain intake - that would be around 5,000 heifers.]

Timing of 2nd Vaccinations

 

Dr. Chris Chase shared data at the recent Discover conference on calves, May 28-31 2013, about the timing of 2nd or booster vaccinations.

 

His data showed significant decreases in "B" cells starting around 16 days after the initial vaccine injection. He characterized the early phase of this drop in "B" cells as eliminating the weakest in this cell population. The more robust cells survive longer.

 

Based on this observation of differential decline in "B" cells his recommendation for second vaccinations is between 17 and 20 days. This captures the maximum anamnestic response (memory cells reproducing in response to the vaccine). Under field conditions, I would add, we have to remember that there is substantial variation among animals in their response to vaccines. This variation may be especially tied to calf health and level of nutrition.

 

This boils down to giving the booster injections sometime in the third week after the initial injection in young heifers. This timing increases the chances of getting the most immunity for the money! 

Colostrum - Good Summary

 

I just came across an excellent summary on colostrum management - something to access and tuck away as a pdf resource. It was prepared by Dr. Michelle Arnold and published as part of University of Kentucky Dairy Notes edited by Professor Donna Amaral-Phillips, Department of Animal and Food Science.

Colostrum Summary