Muskox Mystery: Seven Muskoxen Dead
Animal care network investigates string of deaths at LARS
By Kelsey Gobroski
Sun Star Reporter
The next batch of muskox calves at the R.G. White Large Animal Research Station (LARS) will struggle to fill new gaps in the herd. This wasn’t supposed to be their inheritance.
The ideal herd size at LARS is about 30 to 35 animals, according to John Blake, attending veterinarian and Assistant Vice Chancellor for Research. Before Sept. 20, there were 36 animals in the herd.
Then they began to die.
Seven yearling males died over the course of a month..The most recent death was Oct. 16. The animals were not participating in research. Since then, the entire herd is considered susceptible to the mysterious condition, and all are monitored. Though LARS is home to caribou and reindeer too, only muskoxen have been affected.
The seven muskoxen that died were underweight and low in copper, selenium, and cobalt. Hay grown in Interior Alaska lacks elements needed in well-rounded diets, but employees at LARS supplement every muskox with these substances.
A similar problem killed five muskoxen in 1991. The muskox cows back then were getting dairy cow supplements. LARS responded to the deaths by giving their bulls the same rations, Blake said. Now the supplements aren’t enough, and UAF animal care officials are scrambling to find out why.
The deaths have stopped for now, said Perry Barboza, a wildlife biology professor and nutritionist who works at LARS. Now LARS, Blake, and Barboza must figure out why the muskoxen diet isn’t working.
The calves expected next May were conceived in September. Autumn is mating season and breeding harems lead to unruly and protective bulls. “The bull, of course, is being a bull … he’ll come at you, he’ll roar,” Milan Shipka said. He’s a school of natural resources professor specializing in livestock.
The staff stopped weighing the breeding animals and left them to their own devices, as usual. They kept weighing the younger males, who took no part in breeding. It was during this time that they noticed something was off.
It’s hard to know when arctic animals like muskoxen are sick. “You don’t say ‘I’m feeling a little ill,’ because predators immediately notice that,” Barboza said. He’s been at LARS since 1997.
Blake performed necropsies on the animals and rushed liver tissues to the Washington Animal Disease Diagnostic Laboratory at Washington State University. John Wenz, an epidemiologist from the same university, came up to Alaska for a couple of days to help LARS look through their records for possible explanations, Barboza said.
It’s normal for a muskox to change about one percent in body weight a week, according to Barboza. These muskoxen were losing up to 10 percent of their body weight per week. Muskoxen need to gain weight just before winter, especially when they’re still going through growth spurts as yearlings.
The animals should have been getting enough nutrients. In addition to the dairy cow supplements, the muskoxen were fed willow, which is rich in some of the elements Interior Alaska hay lacks.
There could be other causes for the condition, Barboza said. Copper needs to piggyback on another substance to be absorbed, and that process might be lacking. They might choose to not eat enough filler food like hay. For some reason, the animals might need more of the elements than normal, Barboza said. There could be something present that counteracts absorption, Blake said.
Robert White started LARS in 1979 using a year of NSF funding to convert a farm into the research station. White acquired and raised wild muskoxen from Nunivak Island. “We instigated an extremely high level of care,” he said.
While White was at LARS, the station also began collecting and selling qiviut, or muskoxen wool. After three years, they had animals tame enough to begin their first study.
For 12 years, they left half of the herd to eat nutritionally poor local grasses. The other half also ate high protein supplements. Those with better food produced calves every year, those without gave birth less often.
“Nutrition can have a big effect on reproduction,” Shipka said.
Over the years, examples of other differences between well and poorly fed animals emerged. The poorer area is a lot like what the muskoxen would find in nature. Around rivers they might find a lot of flowering plants and willows – plants higher in nutrients like copper. It’s possible that once muskoxen eat all the plants by the rivers they’re left with fairly low quality forage. That could have happened to a herd released in ANWR that only flourished for about 30 years, White said.
White and Blake were around during the 1991 muskoxen deaths. Blake learned the hay didn’t provide enough nourishment, and started supplementing the animals. White remembered attributing the deaths to summer weather. “I just remember it as one of the events that the animals get sick,” he said. Since retiring in the mid-90s, White’s kept up on the research. The same problems LARS is experiencing can happen cyclically in the wild, he said.
“Nothing in the world is as simple as it looks,” White said.
Although the deaths have stopped, all of LARS muskoxen are currently being treated as susceptible to lethal weight and nutrient loss. Now LARS and UAF’s Institutional Animal Care and Use Committee are looking outside the university for answers. An answer for the scientists who lost future breeding bulls that fetch $3,000 in a free marketplace. An answer for researchers who can’t start new projects on an unhealthy population. An answer for the muskoxen.