12/04/2026
Body Condition Scoring and Calf Immunity
Snapped this photo while we were out body condition scoring the cows this week. (It helps when your bestie is an accredited BCS Assessor that I can shamelessly take full advantage of)
Body Condition Scoring the dairy cow herd is one of those jobs that is very easy to put off when the list is already too long. But if you are preparing to rear those calves that are in utero, this is actually one of the very first steps in calf health.
Because calves don’t just magically appear on calving day fully formed and ready to go. The foundations of that calf, its vigour, its ability to get up and drink, its immune system are all being influenced months earlier by the cow carrying it.
Body condition score (BCS) is one of the simplest tools we have to check whether that cow is set up properly for the job.
There’s a fairly well understood and adopted body of research showing that dairy cows that are too thin or too fat before calving run into more problems. DairyNZ BCS recommendations for point of calving are 5.0 for mature cows and 5.5 for first time calving heifers. Missing that target, either under or over leads to increased risk of difficult calvings, poorer transition metabolism, and impacts on colostrum quality all of which can stack the odds against the calf before it has even taken its first breath.
However, even more nuanced is that there is some work in the Journal of Dairy Science that shows that the dam’s body condition before calving can influence the newborn calf’s immune response. Evidence suggests that the calf’s ability to fight disease is shaped by the nutritional status of its mother months earlier and linked to body condition score.
So in practical farmer terms, the goal is pretty simple. We want our cows to be not too fat, not too skinny, just right. And that's not just an average across the herd, that is as many cows as possible, individually hitting those targets. This means that sweet spot where the cow can calve easily, produce good colostrum, and transition into lactation without burning through her own reserves and also give her calf it's absolute best crack at a long and healthy life.
Because we start calving late July, we’re watching this really closely now. BCS scoring lets us catch drift early so we can actually do something about it. That might mean lifting feed levels for cows slipping backwards, or drying some cows off earlier so they have the runway to put condition back on before calving.
Those decisions made now ripple all the way forward to the calf shed.
Cow health → calving ease → colostrum quality → passive transfer → calf immunity.
And those calves grow into heifers, those heifers become cows, those cows carry the next generation of calves. Around and around it goes.
Which is why the longer you do this job, the harder it becomes to point to the exact moment calf health begins. Because it isn’t really a starting line at all. It’s a circle.
One generation quietly shaping the next, long before we ever step into the calf shed.
