If you put a Grass based Dairy Discussion Group in front of a herd of dairy cows & ask them about the Cow Condition Score (BCS) they will usually respond by saying that "they're okay!"
Why? Why wont they be more objective & more critical of the thinner cows? As Dr Clive Dalton recently wrote in NZ..."A culture has developed over years that if you are ever asked to score someone else's cow always say she's CS 4.5 (NZ) & you won't get into any trouble"
A condition score was never meant as an average. It's a target ALL cows in the herd must reach. Cow Condition Score (BSC) is a visual assessment (reasonably accurate too) of a cows "energy reserves". There are a number of critical points in the year where these target BSC are very important to milk production, fertility & maybe some animal health issues. The most important of these "criticals" is the Condition Score at calving. Given that most spring cows have now calved we need to look at the next two critical points for BSC.
Firstly there is the minimum BSC (sometimes referred to as the nadir BSC) this occurs 50 to 100 days after calving or about 70 days on average. The minimum BSC & the loss of condition post calving varies considerably between cows in the same herd for lots of different reasons. However the BSC at calving is the single most important factor & has a big influence on both the minimum BSC & the loss of Condition post calving. (Extensive review by John Roche et al).
If you can reduce the Condition Score loss postcalving you reduce the postcalving anestrus.
The lower the minimum BSC & the greater loss of Condition (postcalving) both have a negative effect on conception, pregnancy to 1st service & 6-12 week incalf rates.
Low BSC & greater BSC loss are risk factors for uterine infections especially in younger cows.
I have been working with three grass based dairy farmers in England since October 2009...we have been condition scoring every cow thru out the late lactation, dry period over winter, at calving & now 70 days after PSC.
Since calving we have measured a little over one NZ Condition Score loss (av for each herd). That sounds okay as it is within the recommended CS loss range.
However when you look at the data in more detail it reveals that some cows have lost a lot of condition since calving. The risk of these cows NOT conceiving in the 1st 6 weeks is very high.
On closer examination some of these cows had difficult calvings, uterine infections, lameness, some are Holsteins in a XBred herd & a disproportionate number are heifers. Some we just can't explain why they are in this "SAD" group.
We need to sort this asap. Isolate this "sad" group & call the vet. Discuss with your vet possible reasons....which might include eg liver fluke,wasting diseases or mineral deficiencies????
We have to get this group of cows back on track ASAP.
Act NOW pull out the worst 10% cows with low Condition Scores. ARREST any further loss of condition score. SEARCH for reasons why they are so thin compared to the rest of the herd. TREAT any sick cows asap & seek vet help for the cows with unknown reasons for big losses in condition since calving. Finally decide how you might best regain the lost condition....is it best to reduce milk production (OAD) or can you feed this group of cows separately to rapidly regain condition pre PSM.
I'd like to thank Tom Malleson, John Millington & Rupert Major for their patience & active participation in this important Condition Score project.
We hope to produce a really useful set of 'decision support tools' for Cow Condition Scoring so we can identify thin cows early & act early to improve milk production & fertility & to reduce losses of valuable cows from the herd.
What do you think? Please leave your comments below to add to the discussion.