I admit that we started milk testing because my daughters wanted our does to have those fancy stars and letters after their names like *M in ADGA and *D in AGS. However, after getting started, we discovered there are many reasons to be on milk test beyond bragging rights. Now in our seventh year of milk testing, I can’t imagine managing our herd without it. Why? Basically, it allows me to compare all of our does to each other and to other goats of the same breed.
1. I know how every doe’s production compares to other does. No guessing when it comes to deciding which does to sell for low production. Having this is invaluable, as I am often surprised when I look at the totals.
2. I know how much butterfat each doe is producing. If you make cheese, it is great to have this information because higher butterfat means better cheese yield. Unless you send your milk to a lab, you have no way of knowing which does have the best butterfat production. Not only do I get monthly butterfat production numbers, but I can also see their average butterfat over the course of their lactation — and it requires no math on my part! Again, I am sometimes surprised to see which doe has the highest average butterfat. It is not always the one that has the highest butterfat peak.
3. I know if a doe has a sub-clinical case of mastitis. Every sample of milk is tested for somatic cell count, which is an early indicator of mastitis. In many cases, a doe’s SCC will go up before she gets clinical symptoms of mastitis such as a hard, hot udder. When we can catch a mild case of mastitis, I prefer to try alternative treatments such as peppermint oil on the udder, whereas I tend to panic and reach for the antibiotics once a doe has obvious symptoms.
4. I can see a doe’s mature equivalency, which is her projected total for a 305-day lactation. Although it isn’t always 100% accurate, it gives you a good idea of whether or not a goat’s complete lactation will be respectable or extraordinary or in the culling category.
5. I know each doe’s persistency of lactation curve. Prior to milk testing, I had never even heard the term! Now, it is one of the most important things to me. Basically it calculates how quickly a doe’s production declines over the course of her lactation. The lab uses averages for your breed, and the persistency of lactation curve tells you how your doe stacks up to other does in the breed in terms of how well she can sustain her lactation. Goats with low persistency ultimately produce less over the course of their lactation. If a doe’s persistency is 100%, it means she is average. Below 100% means below average, and above 100% means above average. Although you can see how well your doe maintains her lactation by keeping barn records, you can see how your doe stacks up against the entire breed when you see her persistency of lactation curve.
This is Part I in a series on DHI 305-day milk testing. Here is Part II: 5 Steps to Getting Started with Milk Testing. Although we have a herd of dairy goats, this information also applies to cows.