Friday, February 27, 2015

Health Benefits Among Weaned Heifers Associated with
Higher Plane of Nutrition as Preweaned Calves

In a experiment with a small number of Jersey calves researchers orally challenged them with a Salmonella  Typhimurium. These post-weaning calves (80 days old) represented two levels of pre-weaning nutrition - a low level of milk replacer (just under 1 pound of 20-20) [LPN] and a higher level (1.6 pounds of 28-25) [HPN].

After the Salmonella challenge the HPN calves consistently scored higher on a series of indexes that reflect the strength of immune system response to pathogens. In addition, as an indirect indicator of how the calves were feeling, at 9 days after the Salmonella  challenge the HPN calves were eating about 6 pounds of calf starter daily compared to the LPN calves that were eating 1.7 pounds less daily.

So, with these limited data we can conclude that there is a post-weaning health payoff for seeing that young calves have plenty to eat during the pre-weaning period.

As an interesting side note regarding diarrhea among the youngest calves, the reported scours rate among the 7-10 day-old calves was 46 percent for LPN and 88 percent among HPN calves. No explanation was given for what I consider elevated scours rates among both groups. The blood serum total protein levels were quite uniform and high (average =  6.1). I conclude that pathogen exposure during the first day of life must have been substantial because they all started scouring at 7 days of age. The scours lasted about 4 days for LPN calves and 6 days for HPN calves. No long-term negative effects of scouring was reported for either group of calves.

[Reference: Ballou, M.A. and Others, "Plane of nutrition influences the performance, innate leukocyte responses, and resistance to an oral Salmonella enteria serotype Typhimurium challenge in Jersey calves," Journal of Dairy Science March, 2015 Vol. 98, pp 1972-1982] 

Thursday, February 19, 2015

Colostrum from Pastured Irish Cows

I had the opportunity to review an article published in 2013 (M. Conneely et al., "Factors associated with the concentration of immunoglobulins in the colostrum of dairy cows." The Animal Consortium 7:11 1824-1832) that focus on a population of Irish cows. These cows were quite different from USA cows reported in the work of Morrill, et al. ("Nationwide evaluation of quality and composition of colostrum on dairy farms in the United States" Journal of Dairy Science 95:3997-4005 2012). 

In contrast to the confinement-housed U.S. cows with year-round calving this Irish population had seasonal calving and was managed in a grass-based system. The US National Agricultural Statistics Service reported average milk production of 20,400 pounds (305 days) in USA (2010). This Irish cow population managed on a grass-based system had an estimated milk production of 11,600 pounds (305 days). Due to missing data in the Morrill report it is not possible to compare cow populations by breed and parity. 

  • Colostral IgG concentration - wide variation in both populations. Irish low = 13g/l USA low  =<1.8g/l   Irish high = 256g/l  USA high = 200g/l
  • Colostral IgG mean value much higher among Irish cows compared to USA cows.  Irish mean = 112g/l  USA mean = 69g/l.
  • Colostral IgG tended to go up by lactation in both populations.
                                    Lactation - values are grams/liter
                              1        2       3&greater
            Irish         97       99     115
            USA        42       69       96

If I was asked by an Irish dairy farmer about how much colostrum to feed newborn calves given this high quality colostrum my recommendation (based on antibodies delivered) would be 2 liters as soon as possible after birth. Given the wide variation among dams, however, I would still recommend using a Brix refractometer or Colostrometer to check antibody concentration before feeding the calf. More than 2 liters of lower quality colostrum might be a better practice to achieve adequate immunity. 

The Irish study also found that cows milked closer to calving consistently had higher IgG values than those milked with a longer calving-milking interval - longer 9 hours post-calving among these cows seemed to be a break point indicating lower quality.

Monday, February 16, 2015

Getting Equipment Clean Under Cold Conditions 

The February issue of Calving Ease newsletter for calf care persons is now online. Click HERE to access the newsletter.

Key points are:

  • Maintaining wash solution temperature of 120° (49°C) is essential. 
  • Preheat wash sinks before filling with wash water. 
  • Pre-wash rinsing with lukewarm water helps prevent wash water chilling. 
  • Use a floating rapid-read thermometer to check wash water temperature. 
  • Protect your hands with quality rubber gloves and clothes with a wash apron. 
  • Dump and refill rather than trying to “warm up” soiled wash water. 

Friday, February 13, 2015

Protocols Pay Off
Clean Colostrum

It was my first visit to the dairy - October, 2002. The calf manager wanted help with a persistent and widespread scours problem. Among all the things we talked about was the need to check "as-fed" colostrum for bacteria content.

Results from two samples? Both over 180,000cfu/ml coliforms and one sample we estimated around 350,000cfu/ml total plate count. 

We put into place a number of corrective measures over the next few years. The list of best management practices can be seen HERE . After several years of training and retraining staff the situation improved. Naturally this dairy like others suffers from protocol drift and retraining has to be done periodically.

Now in 2015? The farm samples colostrum about three times a year - the latest results just came across my desk. Only one of seven samples had any coliform growth at all (i.e., zero growth) and that one was only 1,900cfu/ml. [For reference, 5,000cfu/ml is an upper threshold for coliforms in colostrum.]

Total plate counts were 9,900, 6,300, 4,700, 4,200, 1,300, 1,300, and 900cfu/ml. For reference, 50,000cfu/ml is an upper threshold for total plate count in colostrum. 

What a long way from 350,000! The best management practices to produce clean colostrum are now considered, "It's the way we do things here at this dairy." It is always good to participate in a successful calf enterprise.

It really is possible to produce clean wholesome colostrum.

Thursday, February 12, 2015

New YouTube Video
Basics of Calf Nutrition by Sam Leadley
Courtesy of DairyCo, UK

I had a lot of fun making this 14 minute video for DairyCo in United Kingdom. Hope you enjoy it. 

Monday, February 9, 2015

Estimating Adequacy of Air Exchange in a Calf Barn

Winter-time air exchange is a challenge in calf barns. The calf barn I was in on February 5th was a good example of this. 

The barn is tucked in among several other large barns so there is no direct access to the prevailing southwest winds common in that location. The day of my visit was one of many since the first of the year with night-time lows in the single digits and day-time highs in the mid-teens - persistent cold, freezing weather.

The barn's curtained sides had the curtain full up on the west side and down maybe a foot on the east side. One 18" exhaust fan was laboring away in the north peak of the building. The occupants were about 30 preweaned calves and another 30 transition-age heifers.

I measured both temperature and relative humidity outdoors and indoors. As you might suspect the readings were higher inside compared to outside.

                                           Temperature (F)           RH (%)
Outdoors                              15                                39
Indoors                                 27                               51

The owner reported having to treat "too many" preweaned calves for pneumonia - a persistent problem during the winter months with many fewer treated calves when they were able to keep both the doors and curtains open. 

I reinforced her decision to seek assistance to install positive-pressure ventilation equipment. In my experience when both the temperature and relative humidity in a calf barn shows clear increases like those shown above there is inadequate air exchange. And, almost without exception, many of the calves in these barns require treatment for clinical pneumonia symptoms.

As a point of reference on this matter of air exchange rates you may be interested in this resource developed by Curt Gooch at Cornell; click HERE for the table of recommended air exchange rates for different seasons of the year for four different age groups of heifers. 

Thursday, February 5, 2015

When is a Pound Not a Pound?

Question: When is a pound not a pound? 
Answer: When one is guessing about the amount of milk replacer powder being fed!

A calf consultant friend related this event to me yesterday.

She visited a dairy farm in late January. The calves looked thin and many showed symptoms of diarrhea. Many of them required treatment with antibiotics. She suggested that the dairy should consider feeding more milk replacer - supposedly they were feeding one pound of powder daily (about 8 ounces of powder mixed into two quarts twice daily, mixed in individual pails for each calf).

Her recommendation was to increase the feeding rate to about 1.3 pounds or around 21-22 ounces daily. The idea clearly was to do a better job of meeting both the maintenance needs of calves and giving them some extra energy for growth.

The reaction was resoundingly negative. No. No. No. This feeding rate would make the scours issue that was not good even worse. No. No. No.

Give her credit for not just walking away given this response. She persisted and suggested that they weigh the milk replacer that they were currently using. 

Here is the surprise! They were mixing one pound of powder in two quarts of water for each feeding. Yes, that is correct. They were mixing a cocktail with incredibly high concentration of solids. Add to this that the dairy was quite casual about making sure calves had free-choice water. It is no wonder that the calves had diarrhea. 

If I understood the conversation correctly the dairy agreed to cut back to about 10 ounces of powder mixed in two quarts of water - that's a little under 15 percent solids, down a lot from the milk shake that they were feeding. 

So, when is a pound not a pound?

Answer: When there is personnel turnover - the person leaving trains the new person - have this happen twice and the new person's performance has little connection to what should be happening. The one pound per day turned into one pound per feeding!

Moral of the story? Having current employees train new ones can be a risky business.

When I hear how the calves are doing with the new feeding program I will pass it on to you. Have yet another good day.

Wednesday, February 4, 2015

How to Add Bacteria to Milk Replacer

Seriously, I do not have clients that have the goal of adding bacteria to milk replacer. However, I do have clients whose milk replacer when consumed contains many bacteria.

Question? How do the bacteria get into the milk replacer?

A case study.

Milk replacer is mixed in 55 gallon plastic drums. Then it is pumped through a drag hose to deliver it to the calves. In order to get to the calf the milk replacer goes through an intake hose going to a pump. It goes through the pump through a long plastic hose that is dragged from pen to pen. Squeeze a "gas-pump" type nozzle and out comes the milk replacer. The calf drinks from a nipple bucket. 

Presto, like magic, the samples from this client last week had these bacteria counts!

  Sample Site                           Coliform            Total
                                                bacteria              bacteria
                                                (cfu/ml)              (cfu/ml)
Mixing barrel                             300                    2,300

From feeding nozzle               1,500                    5,500

From nipple                            8,500                   23,700

Clearly, it is not difficult to add bacteria to milk replacer.

Just for reference, in my consulting work I use upper thresholds of 1,000 cfu/ml coliforms and 5,000 cfu/ml total plate count as goals for feeding either milk or milk replacer in order to achieve reasonably cost effective levels of calf scours. 

Manually cleaning a big open barrel is not difficult - 5 gallons of water, detergent and a brush. Seems to work reasonably well. 

Cleaning a long plastic drag hose and the plastic nozzle - not so easy - have to pump fluids through the intake hose, pump, drag hose and nozzle. Maintaining wash solution temperature above 120F (49C) is a challenge - especially when feeding in a cold barn in February in New York State.

Cleaning nipple buckets and nipples appears to be the big challenge - note the 10 fold increase in total bacteria from the barrel to what went into the calves.

How to reduce contamination levels in the future?

1. Quick and dirty solution is to use a strong chlorine rinse (500ppm) just before using any of the feeding equipment - especially the nipple buckets.

2. Not so quick solution - current wash protocol for nipple buckets is to wash in 110F detergent solution with a quick swipe using a stainless steel scrubber. Revised wash protocol I am suggesting is to rinse with lukewarm water before washing (no rinse currently), wash in detergent solution never less than 120F using a stiff bristle brush.

Even with the improved wash procedure I still lean toward the pre-use sanitizing rinse.

Maybe in March I will have another set of samples with fewer bacteria.