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Ranchers who use late fall and
winter pastures that are short on stock water (or where water
freezes up in winter) can often let cows utilize snow in place
of water, in regions that get adequate snowfall. Horses, sheep,
and many types of wildlife can get by on snow as their only
water during winter (even lactating ewes can meet their water
requirements with snow), but no studies were done on cattle use
of snow until the late 1970’s. A few ranchers had discovered
that cows can manage on snow, but several research studies in
Alberta during the 1970’s and 1980’s, and a study in the late
1980’s at the USDA-ARS Fort Keogh Livestock and Range Research
Laboratory at Miles City, Montana, by Don Adams (now a Professor
of Animal Science at the University of Nebraska-Lincoln)
confirmed and documented the feasibility of this use.
A rancher in southwestern South
Dakota, Connie Quinn, relied on snow in winter pastures for
nearly 20 years. She says cattle can do very well with snow as
their only water source if you have adequate snow, and the right
kind of snow (powdery, not crusted and hard). “That’s sometimes
a problem here,” she says. “We get some warm/cold weather
patterns in which the snow thaws and then freezes, making it
crusty and harder for cattle to eat. You have to monitor the
snow and you need an alternative water supply or a place to move
the cattle to--if your snow runs out or conditions get bad for
the cattle to eat it. You walk a fine line, sometimes, but use
of snow can help stretch fall and winter pasture.”
“It can allow you to use pastures
differently and more efficiently,” she says. “We operated mainly
on leased land where we can’t develop water. It’s native
grass--short, mid-grass prairie--which is cheap feed if you can
use it. These pastures also have protection for cattle during
winter storms; they can get down in the draws and gullies out of
the wind.”
The use of snow in place of water didn’t change the production
of their cattle in any way. “We still managed to get a 90-plus
percent weaned calf crop,” says Quinn. Conception rates and
weaning weights stayed the same.
Their dependence on snow came
from necessity. “We lost some of our leased ground, so we
developed some water and it was a long way from the grass. We
were pulling the cows in every day with some cake, to make sure
they were coming in to the water, because they were not coming
to water on their own. We realized they knew where the water
was, and there must be a reason they were not coming in, and
discovered they were eating snow. After that, we started letting
them use snow more exclusively. We started doing it more
extensively, based on studies in Canada. Some years our cows
have gone as long as 50 to 60 days on snow alone.”
She remembers opening up stock
water in sub-zero weather when she was growing up, in big
pastures where cattle would be so scattered they sometimes
didn’t get to the water before it froze up again. Yet the cows
did all right.
After their experience with the
cattle not coming to water unless they were attracted by feed
supplement, Quinn heard a talk by Canadian researcher B.A. Young
at a range beef cow symposium. At that point in time, Young had
conducted the only research on snow as a water source for
cattle. Quinn was interested in this research, and later
contacted Don Adams at University of Nebraska, after Adams did
an extensive winter water consumption study at the Range
Research Station at Miles City, Montana.
Adams fitted each cow in the
study with an electronic identification tag. “Cows could access
water only in a stall with a small water bowl with an electronic
water meter,” recalls Adams. “When individual animals entered
the stall one at a time their identification, date, time of day
and amount of water consumed was recorded.” He found that the
average water intake per 1000-pound cow was 4.3 gallons per day,
but also discovered that 2 percent of the cows drank no water at
all during the whole study period (November through February).
“Because there were no other water sources for the cows to drink
from, I concluded they were eating snow, and that they preferred
the snow,” says Adams. He noted that snow was readily available
and it did not crust with ice during the study.
He also found that only 65
percent of the cows drank water every day; the others drank
water every second or third day, eating snow the rest of the
time, and some never drank water at all. “Drinking patterns and
water consumption did not affect change in body weight and body
condition score through the winter. It was impossible to tell,
by looking at the cows, which ones were drinking water and which
ones were using snow,” he says.
Adams suggested that cattle
producers monitor cows closely when first starting a program of
utilizing snow, in case naïve cattle are slow to figure it out.
“Also make sure the snow does not become crusted with ice. If
they are unable to lick snow, other steps must be taken if cows
do not consume adequate snow to meet their water needs,” he
says.
In Canada, Young’s early studies
at the University of Alberta farm at Edmonton—a region with
long, cold winters where there is usually snow on the ground
from December to April--looked at how cattle adjust to eating
snow. He found that it is a learned behavior rather than
instinct. Cows learn by watching other cows eat snow, but those
with no role models may go thirsty awhile before trying it.
He confined two steers in a pen
where the only water source was a large container of snow. The
steers searched for water (and bellowed) for two days before one
of them finally tried the snow. The other steer quickly followed
his example. After that, both steers readily ate snow whenever
they were put into a situation without water.
Young’s later experiments dealt
with methods for estimating snow and water intake, and the
ability of free-ranging cattle to obtain their water needs from
snow when water was denied or restricted. He also looked at
effects of eating snow on body temperature and metabolism, and
at average daily gain and water intake of beef calves given snow
as their water source, comparing their performance to calves
with continuous access to water.
Several of the concerns about
snow were dispelled by studies in Canada and at Miles City. It
has been thought that eating snow during cold weather would
cause the animal to expend too much energy in warming it. If the
animal must produce extra heat to melt and warm the snow to body
temperature, this would theoretically take 15 to 20 percent more
total energy (and thus more total feed). Cows in the studies,
however, had similar feed intake and weight gains whether using
water or snow. The cattle eating snow did change their eating
behavior, eating more slowly. They would eat awhile, lick up
snow, eat some more, lick snow, etc. Cattle with access to snow
consume small amounts of snow throughout the day, whereas
animals using water drink only once or twice a day.
The intermittent feed and snow
consumption seems to minimize thermal stress; the heat created
by digesting the feed is enough to melt the snow and warm the
liquid to body temperature. Digestion of roughage, through the
fermentation process in the rumen, always produces heat. In
field tests on beef cows on winter pastures in western Canada,
there were no increases in winter feed requirements of cows that
had access to snow as the only moisture, compared with cows
having access to water.
It has also been thought that
cows deprived of adequate water would be more at risk of
impaction, not having enough liquid in the digestive tract. In
actual fact, impaction of the rumen or some other stomach is
only a problem when cows must utilize dry forage with low
digestibility. Cows with adequate nutrition (proper protein and
energy levels--which may mean supplementing some types of winter
pasture) don’t have a problem using snow instead of water. The
deciding factor on whether cattle can winter on some ranges is
not the water source so much as the nutritional content of the
feed. Low protein dry grass is not adequate for growing animals,
and even mature cows may need a protein supplement to utilize it
best.
Another study looked at average
daily gain in calves offered snow as their only water source
(results published in Canadian Journal of Animal Science, June
1990). Ten weaned calves (Charolais and Angus) were kept in a
feedlot for two months, then split. Five of them were denied
water for 112 days during winter, with access to snow, and the
other five had continuous access to water. All calves were then
given access to water for a further 56 days. There was no
significant difference between the groups in their water intake
or their average daily gain, except at the very beginning of the
final 56 days when the “snow” group drank more water per pound
of body weight than the calves who’d had continuous access to
water. The only other difference, during the time the group was
split, was that the “snow” calves ate more slowly, alternating
their eating with bouts of snow licking. The total amount of
feed intake was the same.
If snow is readily available and
cattle learn to use it, they do just as well as if they had
access to water. They do best if snow is powdery, so they can
sweep it up with their tongues. Adult cattle on winter pastures
can do very well on snow--as long as it’s not so deep that it
covers the forage. As the South Dakota ranchers explain, they
want enough wind to blow the snow off the ridges and expose the
grass, but not so much that it crusts or compacts the snow. If
conditions are right, use of snow as a water source can enable
many producers to utilize cheap winter pasture and help cut
winter feed costs.
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