A cow herd standing in a pond or under shade trees can be a familiar sight on hot days in fescue country of the South and Southeast. For animals grazing endophyte-infected fescue pastures, such scenes can also be a worrisome symptom.

The endophyte, which provides the plant with its hardiness, can compromise an animal's ability to control its body temperature, resulting in reproductive issues, as well as other health and maintenance problems. It's long been a source of frustration for producers, and a drain on their pocketbooks.

There are endophyte-free fescue varieties available (See “In Tall Fescue,” March BEEF, page 37). And, producers can manage around infected fescue's growth cycle to minimize the endophyte's risk to their herds.

But a handful of producers are claiming success with feeding Tasco, a supplement made from brown seaweed, that appears anecdotally to minimize the reproductive challenges of endophyte-infected fescue in cattle consuming it.

BEEF first chronicled Tasco's benefits in a September 2001 article “From Surf To Turf.” Manufactured by Acadian Agritech in Nova Scotia, among Tasco's benefits are enhanced immune response, increased tolerance to hot and cold weather, and reduced stress. Since then, other benefits have been documented — most notably, in the reproductive arena.

“We've had producers who are feeding Tasco notice more cows getting bred and they're shortening their calving intervals,” says Dan Colling, nutritionist in the animal science division of Acadian Agritech.

Unproven in research

While several herds have reported positive benefits, it hasn't yet been proven through research, says Rick Evans, a Mississippi State University livestock reproductive specialist who's worked with Tasco for five years, feeding it to steers and his cow herd.

While he was able to measure improved results in his steers after Tasco, he wasn't able to scientifically prove any reproductive benefits to the cow herd.

“We could never demonstrate a reproductive benefit,” Evans says. “Our cow herd is pretty well-managed to begin with, and our reproductive rates are high. We saw some numerical differences, but we could never prove any statistical difference.”

But, he adds, because Tasco reduces body temperatures in cattle up to a half a degree, there should be a real benefit.

“I've heard folks talk about pretty phenomenal results, but those are producer testimonials, not proven research,” he adds.

Rick Miller, Reeds Spring, MO, began feeding Tasco to his 150-head, Angus-based herd three years ago. He rotationally grazes his herd on fescue pasture and feeds fescue hay in the winter. He began feeding Tasco in a mineral mix three years ago and says he's noticed an increase in conception rate and a significant shortening in his calving period.

“My conception rate went from 93% to 95% and has stayed there,” Miller says, while shortening his calving period from 100 days down to 70, with a goal of 60 days. Shortening his herd's calving interval has improved his ability to sell more uniform lots in the sale barn, he adds.

“Tasco is another notch that helps us upgrade this fescue, and helps keep the cows out of ponds a little more,” Miller adds. “I'm going to keep feeding it because I've seen an improvement, but it's important to keep in mind that it isn't a miracle cure.”

Miller also co-owns an excavating company with Doug Blevins, who runs 300 cows of his own and began feeding Tasco about the same time as Miller.

Blevins has spring and fall calving herds, with 220 head calving in the spring. Since adding Tasco, he says 90% of his spring herd calves in two heat cycles.

“Of 220 head, we had 98% rebred last year,” Blevins says. “And, since I've been using Tasco, we've had 96-98% rebred every year.” (See Table 1 for comparisons.)

The bull factor

A couple of years ago, Joe Bill Meng, genetics director of Creekstone Farms in Kentucky, had two groups of fescue-raised bulls fertility checked and every bull passed. It was the first year he fed Tasco.

“Our veterinarian commented on what a high motility the semen,” Meng says.

Prior to feeding Tasco, he says they normally have to recheck about 10% of their bulls in each group, but when both groups of bulls passed — 75 bulls total — they had to chalk it up to more than just luck.

“We went off it for a period of time and we went back to where we had to recheck bulls that had an occasional problem,” Meng says.

Colling estimates Tasco costs about 75¢/head/month to feed, with the recommended amount of 0.5 oz./head/day mixed into a mineral supplement.

“We suggest starting to feed it a minimum of 30 days before turning the bulls out — to both the cows and the bulls,” Colling says. “Most producers who feed it say it's easier to feed the mineral year round, especially if you're feeding fescue hay in the winter,” he adds.

Table 1. Tasco testimonial

Calving more than 200 calves/year, Doug Blevins compares his 2002 results to 2003.
Calving after: 2002 season 2003 season with Tasco
21 days 57.45% 76.6%
42 days 85.10% 90.07%
63 days 88.60% 99.29%
84 days 97.16%
“Vet called 195 of 200 cows (97.5%) pregnant with calving to occur in less than 60 days for the 2004 calving season.”
— Doug Blevins, SW Missouri