You just received a new load of hay in to your barn. It smells so good, and looks just like the last load you got from your regular supplier. But is it really the same? While it might be similar, growing and harvesting conditions vary with every single cutting, and that can have an impact on the nutrition contained in that sweet-smelling pile of bales in front of you.

Generally speaking, the differences aren’t going to be very big – but the next time your horse mysteriously starts losing weight, or losing muscle condition over his topline, you might want to question your hay supplier or get your hay tested.

For example – if your hay got rained on after it was cut, the rain can shatter the leaves, which is where much of the highly digestible protein is found in your hay.  And given how much of your horse’s daily diet is made up of hay, a small decrease in protein can have a big impact.  Let’s take a look at the math behind this:

A 1000 lb horse should eat 1.5-2.0% of its body weight per day in forage – that’s 15-20 lbs!

• Hay A has 10% protein: 20 lbs of hay x 0.10 protein = 2 lbs of protein intake per day
• Hay B has 8% protein: 20 lbs of hay x 0.08 protein = 1.6 lbs of protein intake per day

In this scenario, you’d have to feed an extra 5 lbs of Hay B per day to be feeding the same total protein as Hay A provides!

But how much difference does this really make, you ask? If your horse’s intake is already on the low end of protein requirements for his size and activity level, then a 2% drop in hay protein would potentially show up in 2 to 6 weeks. Over that time, all else being consistent, a decrease in general muscle tone, and muscling over the topline, will start to appear. Fortunately, it’s pretty easy to combat – in many cases, simply tossing in an extra flake or two of hay per day, or adding a ration balancer or 1 – 2 lbs of grain per day, at feeding time will combat the decreases – and what horse won’t love you for that?