Checking the vat when it counts

Every so often, I look at the dashboard in my car and see one of the red lights warning me that something is amiss. I rely on this safety feature to help me protect the engine and minimise the risk of running out of fuel. Running an enterprise is a lot more complex than a dual-cab ute, but it is just as important to have reliable indicators that warn you of a potential problem looming just down the road.

A great advantage that a dairy farm has over most other agricultural enterprises is that it receives immediate feedback about its day-to-day management – via the vat. Every day the volume and components of milk tell us what is happening in the herd. We’ve all seen changes in milk volume after moving the cows to a particular paddock. And we’ve used that information as an immediate indicator of pasture quality or quantity.

Bulk Milk Cell Counts (BMCCs) are also an indicator – they tell us about the level of mastitis in a herd. White blood cells are part of a cow’s natural defence against infection. A rise in white cell counts in milk is in response to bacteria entering the udder. No factor other than infection causes a significant increase in cell count during lactation.

BMCCs can therefore give you a guide to the number of cows with subclinical infections.

A field “rule of thumb” is that each 100,000 white cells per millilitre of milk (cells/mL) in the BMCC indicates that an extra 10% of thecows are infected with mastitis bacteria. So if you’ve got 200 cows and a BMCC of 200,000 cells/mL, you are likely to have about 40 cows with infected udders.

This is only a rough guide, but it gives you a reasonable starting point to assess your herd. It is usual to average the BMCC over a number of counts when assessing the overall herd picture. For herds receiving daily counts, the monthly average is a good figure to use.

Changes in BMCC can also give you an early indication of whether mastitis is spreading.

For example, if a herd’s monthly average BMCC rises from 200,000 in September to 300,000 in November, then it is a strong signal that the level of mastitis in the herd is increasing. This is extremely important feedback on the effectiveness of mastitis control measures being implemented on a farm.

Bulk Milk Cell Counts are standard indicators of milk quality for most farms in Australia with many farms now receiving that information on a daily basis. But like all feedback, it is only useful if you look for it and then act on it.

Using BMCC to your advantage

Countdown recommends that you organise a system to check BMCCs regularly on your farm, and set “trigger levels” that warn you when you need to take action.

A simple graph shows trends better than most people’s memories. Placing this on a whiteboard in the dairy and up-dating it every 10 days, lets everyone who milks your cows know how the herd is faring. It also keeps everyone focused on the job of mastitis control.

It is also essential to set BMCC “triggers”. A trigger is a bit like the warning light on the dashboard. It tells you something needs checking - soon.

It is helpful to think about BMCC triggers in light of your own farm milk quality goals -and the buying standards of the dairy company you supply. For some farms, premium payments are now set at 150,000 cells/mL. Others are at 200,000 or 250,000 cells/mL. It goes without saying that to keep your dairy farm profitable, it is important to be well within the limit of premium for your dairy company. BMCCs in this range not only attract premium prices, but also ensure the best productivity from the udders you are milking.

One useful trigger is “more than five consecutive 10-day periods above the premium threshold”. This trigger is warning you to seek help from your field officer, veterinarian, or other adviser who works on milk quality and mastitis issues.

Check the vat count regularly – it doesn’t take much longer than checking the dash in your vehicle. And don’t let BMCCs triggers pass without action at any stage of lactation. Simple, effective and inexpensive changes to reduce mastitis are possible on virtually all farms where BMCCs are higher than required. It doesn’t make any sense to motor on, hoping the warning light will go away. After all, the reason it is there is to help you avoid costly breakdowns.

Page 2

Can cell counts be too low?

As farms work towards lower Bulk Milk Cell Counts (BMCCs), the question, “Can cell counts be too low?” is often raised. It is important to understand how white blood cells work to protect udders before answering this question.

Healthy quarters with no infection or inflammation have cell counts between 20,000 to 200,000 cells per millilitre of milk. But nearly all are below 100,000 cells/mL. These “resident” cells are a cow’s early warning system. If bacteria enter the udder, the white cells release chemical messages to call in additional defence cells from the blood stream. Under severe bacterial challenge, billions of white blood cells may actually be required to overpower the infection.

The key aspect of protection is to have a fast response time in calling in reinforcements, rather than having large numbers of cells present. It is more important to have cows in good body health, with readily responsive immune systems, than to have lots of cells waiting in milk.

Cows are not more prone to infection at low BMCCs (below 100,000), and there are real productivity benefits from low cell counts.

From the Farm Guidelines

In herds with BMCCs below 200,000, a sudden increase (of 10% or more) may indicate that a clinical case has been missed. Herds with higher BMCCs have much more fluctuation of BMCCs on a day-to-day basis because there are so many infected quarters.

11.3 Check for clinical cases – undetected clinicals can cause BMCCs to rise.

If your BMCCs are usually less than 200,000 cells/mL, a 10% rise may indicate a missed clinical case.

Glen Beath

Welcome to Glen Beath: Countdown’s man in SA. Glen is a vet with 25 years in dairy practice at Willunga, south of Adelaide. Along with Bernie Mason at Murray Bridge he has been delivering the recent Countdown Farmer Short Courses in SA.

Everyone who knows Glen loves his energy and enthusiasm. He says he is strategically placed on the Fleurieu Peninsula to enjoy life to the full – surrounded by great dairy and wine industries.

Glen has joined us because he’s keen to help SA farmers with some of the key issues he believes they will face over the next few years. In particular he feels they will have a huge demand for well trained employees, and need for support in mastitis control and animal welfare planning.

Glen will co-ordinate Countdown activities in conjunction with the SA Dairy Network at Flaxley. Two more courses are being planned for SA in November and December. Phone 1800 777 530 for more information.

Images:

Pauline’s page:

1. Pauline
2. Ute behind cows – no caption.

Second page

1. Bacteria in milk cause a rise in cell counts
2. Glen Beath