I need to continue with my Chronicles of #ThePile by passing on a little #AgNerd vocabulary. I’ve been in the office for the past few weeks, reading research papers and background on my project. Writing the literature review for my Master’s degree program is proving a difficult task in the middle of summer. I have to keep telling myself the more I accomplish now, the less it’ll hurt later.
I’ve been asked more than once what is the difference between a cow and a heifer. A heifer has not given birth to offspring. A cow has given birth once or more. To be more specific, we can break it down into more technical terms.
Here’s a new addition to my beef cattle glossary:
- Parity– Number of different times a female has had offspring.
In this case we’re talking cattle, of course I reckon it applies to any female who bears offspring. Cows are classified into 3 parities.
In reference to this Summer (2012), this nulliparous heifer would have been born Spring 2011. She was bred at the age of 15 months of age and will calve at 24 months of age. If this sounds like a very young animal, don’t be alarmed. Cattle will reach puberty and start estrus cycles a month or two before breeding age.
The goal is to have heifers close to 65% of mature weight at breeding, and 85% of mature weight when having their first calf. For a cow who will be 1,100 pounds when full-grown that’s approximately 715 pounds at breeding and 935 after first calving.
This primiparous cow was born in the Spring of 2010 and had her first calf in February 2012. Best management practices aim to breed nulliparous heifers so they’ll have their first calf a month ahead of the mature cow herd. This gives the primiparous cows an extra 30 days to regain weight, provide nutrients for peak milk production, and prepare her reproductive tract for rebreeding.
Cows will naturally rebreed within the first few months after giving birth. Farmers actually keep the bulls separated from the cows to give some to recuperate after having birth (I imagine it’s pretty hard work giving birth) and to maintain a uniform calving season. We want cows to calve within a month or two of each other so we can provide adequate nutrition for the entire group easier and calves will be more uniform at weaning and easier to feed.
Ideally we want cows to calve no more than every 365 days. (Remember farming is a business and we have to pay the bills too. Calves are our source of income.) In this case, cows should rebreed within 80 days of calving if they have plenty to eat. This is even without any interventions by the farmer. Any cows that don’t breed back within the specified breeding season will likely be culled (removed) from the group and replaced with younger cows. Reasons for animals not rebreeding are as numerous as the stars.
This cow is multiparous. She was born in 2009 or earlier and has given birth to 3 or more calves. Cows that have given birth 5 or more times are referred to as grand multiparous. These cows will be of mature weight, have fully developed udders (mammary glands). These cows are generally the easiest keepers in the herd – meaning we worry less about calving difficulties (compared to primiparous cows who are may not be mature size) and will generally have a higher rebreeding rate during the breeding season.
Once these cows get to age 7 or 8 (greatly depending on environment or genetic stresses) production starts to decline (peak milk production, maintenance of body weight/condition, and weaning calf weight). This can be attributed to things like wearing down of the teeth or unsound (long, cracked, generally making it uncomfortable to walk) feet. Most cows will remain in the herd from 8-10 years, some lasting 12-15 or even longer.
It’s important to cull (remove) from the herd, cows that do not produce a calf. Like I said before, farming is a business. Cows cost money to feed year-round (Whether on grass or receiving hay/supplement feed). If a cow doesn’t have a calf to sell one year, she can’t pay for her keep and the farmer still has to pay the bills. So the best management is to cull open (not pregnant) cows and replace them with a cow who will have a calf and pay for her feed.
Most cows will go to slaughter after being removed from the herd. These cows may spend time receiving some extra feed while on smaller pastures. Most go straight from grass pastures to market. Everyone claims these cows are just hamburger, but actually many parts are used for whole cuts – think deli meats or roasts. This page from Ontario does a decent job of explaining who meat from a cull cow ends up being used.
Well, what started as a short post in response to one question, ended up with a lot more information. I could have gone on for days about the life of a cow in the beef cattle herd, but we’ll leave it for another post.