A dairy cow requires 21 grams of calcium per day for body maintenance, she produces 23 grams in colostrum and requires 56 grams of calcium to produce 45 kilograms of milk. In summary, her calcium demand triples in only one week after giving birth.
How can the dairy farmer support this calcium need? Jessica McArt, a veterinarian and researcher at Cornell, says to pay attention to what type of calcium you are giving her and how you’re giving it.
First, investigate the calcium source, McArt says. Two important factors are the source’s solubility in water and absorption rate in cattle, McArt says.
“These are unfortunately not all created equal,” McArt says.
(Source: Jessica McArt)
However, dairy farmers may not know the calcium source from reading a product’s label, McArt says.
“We don’t know the calcium source because that information is not typically given by the company,” McArt says.
Even if the calcium source is not known, dairy farmers can control the manner of delivery, McArt says.
“Subcutaneous injection is widely used in the dairy industry,” McArt says. “However, issues with subcutaneous injection is there can be irritation with injections containing glucose.”
Other delivery options include an oral bolus or drenching, McArt says.
“Drenching is not as easy,” McArt says. “If we get it down the trachea, the cow will no longer be hypocalcemic. She’ll be dead.” Those administering the drench should be sure to follow proper administration protocols to make sure the product is going down the esophagus.
Oral boluses have increased in popularity and availability, but they are not without safety considerations, McArt says. McArt says quick delivery is important because calcium salts can be irritating to a cow’s mucosa.
“Next time you’re administering them, lick one,” McArt says. “You’ll see how quickly they can irritate a cow if they become lodged in the throat.”
Boluses coated with fat may more quickly pass through the cow’s esophagus, McArt explains.
“The cow decides if the bolus goes down easily,” McArt says. “We can do wrong by the cow if we administer it incorrectly.”
Amidst these different delivery methods, what is one certainty?
“If we can do what we need to with prepartum nutrition,” McArt says, “We don’t have to be as aggressive with post-partum treatment.”