Friday, March 27, 2015

Reminder: Heifers Can Have High Quality Colostrum

This week I reviewed research dealing with colostrum composition. One of the reports documented variation of antibody (IgG) concentration by lactation number of the dam. [S.I. Kehoe and Others, "Comparison of immunoglobulin G concentrations in primiparous and multparous bovine colostrum." Professional Animal Scientist 27 (2011):176-180.]

Three central Pennsylvania herds provided the colostrum samples. They were well-manged herds ranging in production from 19,500 to 26,900 rolling herd averages. Colostrum was collected in the range of 2 to 6 hours post calving. Average IgG concentration by lactation showed:

1. All lactations averaged well above the minimum threshold for colostrum to use for first feeding (>50g/l).
2. By lactation the values were:
     1st     83.5g/l
     2nd    92.9g/l
     3rd   107.4g/l
4th +     113.3g/l

Note that 1st lactation average was far above the 50g/l threshold for first feeding. 

"So," you say, "why should I bother to check colostrum for IgG concentration?

At the 4-quart yield level including colostrum from all lactations the lowest IgG value was 20g/l and the highest value was 200g/l. Even on dairies like this roughly one batch of colostrum out of ten had substandard IgG concentrations.

If you are using a Brix refractometer to check colostrum quality you may want to read this resource sheet with tips for getting valid readings. Click HERE for the Brix resource. 

Thursday, March 26, 2015

Cost of Rearing Heifers in UK

I recently received this reminder of the availability of this report on cost of heifer rearing in UK. It is well done and most informative. 

If you missed DairyCo’s webinar on Wednesday night, it can be viewed on youtube:

DairyCo YouTube channel.

Your levy money has funded a comprehensive study into the cost of calf rearing in GB in 102 herds across all year round calving, split block calving, spring calving and autumn calving patterns.

Among the headlines:

·         Average age at first calving was 25.8 months
·         Calving at 24 months reduces rearing costs by 16%
·         Increasing the proportion of grazed grass in the diet reduced rearing costs
·         It takes on average 1.5 lactations to pay back rearing costs
·         But, the range in payback is from 168 days to 2000+ days!

DairyCo resources on calf management can be found on the DairyCo website

If you only want to see the part on repayment period you can click at 17:45 on the recording and you can get just that part. I also noted that the non-completion rate for the 102 herds in this study was 22.4% (birth to calving loss rate). 

Monday, March 23, 2015

Colostrum Antibody Concentration at
2nd and 3rd Milking

In general we know that antibody concentration goes down from milking to milking after a cow has a calf. 

Davis and Drackley (The Development, Nutrition and Management of the Young Calf, 1998, p 182) reported this concentration declining this way:
1st milking     100%
2nd milking     70%
3rd milking      40%

In a 2005 presentation at the Mid-Atlantic Conference J.H. Herbein reported somewhat similar data separately by breed: (this is a limited data set including both conventionally fed and grazed dairy cattle)

Holstein data
1st milking    100%     95g/l
2nd milking    77%     73g/l
3rd milking     45%     50g/l

Jersey data
1st milking     100%    63g/l
2nd milking     70%     50g/l
3rd milking      56%     35g/l

Bottom line
If you have a practical way to harvest and feed 2nd and 3rd milking to calves this product will do a great job of providing surface immunity in the gut of these babies. Remember this product must be collected and handled in a way that it has a low bacteria count in order have healthful consequences.

Wednesday, March 18, 2015

Enough Hot Water

The March 2015 issue of the newsletter for calf rearer's is now online. 

Click HERE to access the newsletter file.

The key points:
What is your water demand? How much at what temperature and when? 

How much hot water do you actually need?  

How big a hot water tank will be needed to meet our peak demand needs?

The letter contains a link to tables used to estimate delivery and recovery rates used when sizing a hot water heater. 


Friday, March 6, 2015

Heat Treating Colostrum - Revisited

"The objective of this randomized clinical trial was to describe the effect on colostrum characteristics and passive transfer of IgG in neonatal calves when using the Perfect Udder colostrum management system ... compared with a negative control (fresh refrigerated or fresh frozen colostrum) and a positive control (batch heat-treated colostrum)."

 The colostrum was handled these ways:
1. heat-treated in Perfect Udder bags
2. heat-treated in a batch pasteurizer
3. fresh frozen
4. fresh refrigerated

The standards that I use to define upper levels of bacteria in "as-fed" colostrum are:
A. No more than 5,000 cfu/ml coliforms
B. No more than 50,000 cfu/ml total plate count

How did these samples compare to these standards?

   Sample (as-fed, warm)                       Coliform        Total Plate     My comment
                                                              (cfu/ml)         (cfu/ml)
1. heat-treated in Perfect Udder bags    3                    16,000             Okay to feed

2. heat-treated in a batch pasteurizer    10                    4,000              Okay to feed

3. fresh frozen in Perfect Udder bags    6,500              400,000           Marginal

4. fresh refrigerated, PU bags                65,000            3,000,000         Bacterial soup

Heat treating did not change the antibody concentration in the colostrum - all the samples tested between 77 to 80 grams per liter. We often use 50g/l as the dividing line between good and poor quality colostrum. These 59 pound calves received 4 quarts of this colostrum so their antibody intake was over 290 total grams at first feeding.

Efficiency of transfer of antibodies into the blood of the calves was higher for the heat-treated compared to the fresh colostrum.
                                                                   Efficiency of absorption
1. heat-treated in Perfect Udder bags                   37
2. heat-treated in a batch pasteurizer                   37
3. fresh frozen                                                      32
4. fresh refrigerated                                             32

Because all of the calves received well over 290 grams of antibodies in their first feeding that was between 77 and 88 minutes after birth, in spite of the high bacteria counts in the fresh colostrum that compromised antibody absorption, all the calves still had reasonably high immunity (blood serum total protein values above 6.5g/dL where 5.5g/dL is considered successful passive transfer). [Just for reference here our goal for first feeding is at least 200g/L of antibodies.]

These Jersey calves only averaged 59 pounds at birth. In this situation we might have advised the dairy to consider feeding 3 quarts rather than 4 quarts of colostrum to achieve adequate immunity.

For a fact sheet on heat-treating colostrum click HERE.

Monday, March 2, 2015

On-Farm Testing of Colostrum Quality

In a recent report of on-farm testing of colostrum quality both a Colostrometer and Brix refractometer were used. For comparison the research team used an in-laboratory test as well. 

The research team reported, "If a sample tests lower than 80g/l (grams per liter) on the Colostrometer, there is a 60.6% chance that is truly poor quality [less than 50g/l] and if it tests higher than 80g/l, a 92% chance that it is of adequate quality."

"A sample testing lower than 23% Brix has a 61% chance of being truly inadequate, whereas a sample testing higher than 23% Brix has an 85.5% chance of being adequate." (p1880)

So, why are we testing? We especially want to avoid feeding inadequate quality colostrum - less than 50g/l value. Remember we are trying to feed at least 200 grams of antibodies in the first four hours - that is our minimum threshold

Rereading the text above we find that both the Colostrometer (80g/l) and Brix refractometer (23%) will identify about 60 percent of the samples that are truly poor quality [50g/l] if we use these values as lower quality thresholds. The new information in this research for me was the need for using a higher threshold when using the Colostrometer if I want to be confident that the colostrum is not of poor quality - I have been using 50g/l (the dividing line between the green and yellow zone on the Colostrometer) and I need to think about using a higher value. 

Among these 13 herds in Alberta, Canada, province the antibody levels among cows varied widely from a minimum of 8g/l to a maximum of 129g/l. More of the low antibody samples came from first and second lactation cows compared to those third lactation and greater. 

Reference: Bartier, A. L. and Others, "Evaluation of on-farm tools for colostrum quality measurement." Journal of Dairy Science 98:1878-1884 March 2015