October 3, 2013
Spaying heifers is a management tool that’s nearly a century old. It involves surgical removal of the ovaries — the primary source of estrogen and progesterone in females — thus eliminating estrous cycles and pregnancies.
For heifers destined for beef production rather than calf production, spaying has distinct advantages. Spayed heifers can be grazed or fed with steers without riding activity or worrying about the neighbor’s bull coming through a fence. Plus, heifers guaranteed as open and non-cycling draw premiums from some feedlot buyers.
Daryl Meyer, a North Platte, NE, veterinarian, has spayed thousands of heifers. He says spayed heifers generally are calmer than their intact counterparts. “They handle more like steers. They also gain better. If everything is equal, spayed females outperform intact heifers.”
Meyer says research indicates that spayed heifers’ performance advantage extends to both pasture and feedlot. “Some feedlot managers say spayed heifers stay on feed more consistently, more like steers. Even when feeding melengestrol acetate [MGA] to intact heifers to halt cycling activity, there’s variance in feed consumption. Spayed heifers, with more consistent intake, get more consistent feed conversion.”
Like steers, spayed heifers can be implanted, and respond better to implants than intact heifers. In fact, spayed heifers that are implanted tend to have more lean tissue and deposit less fat. One study showed average daily gain response to implants was four times greater in spayed vs. intact heifers. And grazing studies indicate a 5.5% gain advantage for spayed, implanted heifers over implanted, intact heifers, Meyer says.
“A combined average of studies over a seven-year period on spayed yearling heifers showed a 2.5%-3% gain advantage, and a 0.1-0.3 lb./day gain advantage for spayed, implanted heifers, if everything else is equal,” Meyer says. He says spayed heifers also finish and reach optimum grade sooner than intact counterparts, with the best gains coming in conjunction with implanting.
Feedlots prefer spayed heifers because pregnancies are no longer a management issue. A calving heifer costs a feeder $150-$200/head due to calving problems, infection, decreased gain, decreased carcass quality and yield.
“Preg-checking and administering abortifacients involve time and expense. It also stresses the heifers at a late point in their production phase — setting them back in weight gains. Spaying eliminates these problems. Producers can treat and manage spayed heifers just like steers,” Meyer says.
MGA is often given to intact heifers to suppress estrus, preventing ovulation. Feeding MGA results in increased feed efficiency and gain compared to other intact heifers, but isn’t approved for steers and can’t be fed to groups of mixed sexes.
David Anderson, a Kansas State University DVM, says spaying isn’t without risk, particularly of hemorrhaging and other trauma, depending on the technique. Death loss in spaying heifers can be as high as 1%.
In earlier years, spaying was done with a flank incision, after which the surgeon removed the ovaries with spay shears or some other instrument. This method risks incision-site infections and scarring.
The trans-vaginal technique is faster, less labor-intensive, cheaper and safer. “Heifers bounce back in 2-3 days, whereas flank-spayed heifers might take 5-7 days to get back on full feed,” Anderson says.
Meyer, who began using the vaginal technique in 1983, says another disadvantage to flank spaying is that adhesions may develop. “Packers don’t like flank-spayed heifers because, when they pull the hides off, adhesions tear,” he says.
Anderson says there are two trans-vaginal techniques; both enter through the vagina into the abdomen to remove the ovaries. This can be done by hand, or with a Kimberling-Rupp spay tool that is inserted into the vagina, guided by a hand in the rectum (to locate the ovaries).
“There’s some risk of losing the ovary into the abdomen, which then may have access to blood supply from the omentum or mesentery and keep functioning. The Kimberling-Rupp instrument allows you to pull the ovary out, eliminating that possibility,” Anderson says.
The disadvantages of trans-vaginal spaying are the risks of puncturing the rectum, damaging the bladder or other trauma. “Proper training is important, but it’s a quick and economical way of spaying heifers. People who are good at it can do a heifer in two minutes,” he says.
Meyer says there’s always some chance of hemorrhaging. “Trace mineral deficiency [selenium or copper], or eating clover or moldy feed, may interfere with clotting,” he says.
Cleanliness is important. “You must keep things clean and disinfected. It’s also important to watch heifers closely for several days after spaying, and treat any that don’t feel well with antibiotics. Early intervention is crucial. Sometimes infections occur even if you’ve been meticulously careful and clean on the outside. A heifer might have vaginitis on the inside; the instrument may take it into the abdominal cavity,” Meyer says.
If a heifer is dull, off feed or feverish, he recommends a long-lasting antibiotic and Banamine® to reduce inflammation and help her feel better. “Usually there are no problems, but you have to treat one occasionally. It’s similar to castrating bulls; you need to watch them closely and deal with any problems,” he says.
In most instances, heifers are spayed after puberty. “We prefer them large enough to get a hand in the rectum and manipulate the ovaries, so we want heifers cycling. We can grasp the ovaries more easily,” Anderson says. Many people spay heifers in the spring of their yearling year, before pasture turnout. If they must be spayed younger, the flank technique is used.
“In the future, we may look at chemically sterilizing heifers,” Anderson says. “Vaccines are being developed for male castration, and we may eventually use something like this for heifers, thus eliminating the risks of surgery.”
Market and profit perks
Producers who spay heifers feel it improves marketability. Prices for spayed heifers vary by year and region, but feedlots in general pay a little more for spayed heifers, says Daryl Meyer, DVM, North Platte, NE. “It’s like buying preconditioned calves — the chances of problems are less.”
Blake Nuffer, Montana Livestock Auction, agrees the biggest advantage to spaying heifers is their marketability.
“A rancher can spay heifers he doesn’t want to keep as replacements, and get more money for them. Spayed heifers may bring $5-$10/cwt. more than intact heifers of the same age/weight. Most buyers are receptive because they know they won’t have problems. Most feedlots don’t like feeding heifers, but spayed heifers continue to gain better during the feeding period,” he explains.
Even without a price premium, producers still reap added performance in the growing period. “If heifers are 100 days on pasture and gain just 0.01 lb./day more than they would as intact heifers, that’s an extra 10 lbs. at market time,” Meyer says. Some gain even more. At a cost of $5-$7/head for the spaying procedure, the added pounds can more than offset the veterinary cost.
Producers who retain ownership of heifers through the finishing phase have additional gain and performance. Merrill Beyeler, a rancher near Leadore, ID, has occasionally spayed his market heifers.
“You can pick the replacements and spay the rest. A few years back, we spayed a group we knew we didn’t want to breed, ran them on grass as yearlings, and finished them ourselves on feed for about 60 days. They did very well. Their average weight was 1,300 lbs., and all graded Choice and Yield, Grade 1 or 2. That made more money than if they’d been open heifers. We only needed to add 200 lbs. in the finishing phase,” Beyeler says.
RJ Hoffman, Salmon, ID, has spayed heifers for 10 years. He keeps all his heifers, breeding the top 75%.
“I pick my replacements in March, put them with bulls in April and spay the rest. I send the spayed heifers to the feedlot in August or early September. Spayed heifers gain better and can live with my replacement heifers, and I don’t have to worry about them being bred. I sell them before they get over 950 lbs.”
Hoffman says his spayed heifers have sold for as much as $2 more than steers, and most years are only $1-$2 lower than a similar steer. He reports that there’s usually an 8-10-cent difference between heifers and steers at 400 lbs., but only a 2-cent difference at 800-900 lbs.
“I sell a load of spayed heifers direct to the same feedlot every year, big enough to finish in 100 days,” Hoffman says.
Another advantage to spayed heifers is easier movement across state lines. Because they won’t be used for breeding, they’re treated like steers. They aren’t bound by the same testing regulations for brucellosis or tuberculosis as intact heifers.
The disease issue is also a factor for people who take in yearlings for grazing. “Many people want only steers or spayed heifers; they won’t pasture intact heifers,” says Daryl Meyer, DVM, North Platte, NE. He says vibrio or trichomoniasis can become an issue, for instance, because fences won’t always deter a motivated bull.
“The last thing you want is custom-grazed heifers bringing a new disease, or enticing a problem bull, into your herd,” Meyer says.
Heather Smith Thomas is a rancher and freelance writer based in Salmon, ID.
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