;ir
. r
-! y Penn State Extension Swine Specialist
LIGHT
Just how the topic of light fits
into hog production isn’t well
understood. Most agree it can
affect performance.
But, to date, we lack standards
on how many hours of light are
needed or what intensity is best. So
I took a look at the research con
ducted over the past 30 years.
Here’s what I found.
Growing-Finishing
Hogs
Given the choice, pigs will
spend about 18 hours a day in the
dark, Canadian studies show.
Other studies seem to parallel this
finding.
When pigs are raised in com
plete darkness, weight gains are
depressed. And conversely, pro
viding more than 6 to 8 hours of
light for growing-finishing hogs is
of no value.
For many producers, the 8-hour
requirement is easy, since most
hogs are grown in modified open
front facilities. But for those in tot
ally enclosed buildings, leaving
the lights on during working hours
makes good sense.
Developing Gilts
One thing is pretty certain
regarding gilts—those in confine-
i ' i
AeatEMVMSßltttMSMlMWg&gsex KaifICSaHMStaCMKSKIMEWeSBK!
t
“Christmas Shopping Does:
Get Any Easier Than This
Give A Gift
That Lasts
All Year...
ONLY $19.00 PER YEAR
$36.00 FOR TWO YEARS
In PA, NJ, OH, MD, DE, NY, VA & WV
(Other Areas $29.00 Per Year or
$56.00 For two Years)
lANCASJER FAMING WILL SEND A GIFT CARD
Announcing The Start Of The Gift Subscription
PLEASE SEND LANCASTER FARMING TO:
(Plum oxnplata all blanks in lull)
NAME
ADORE!
CITY.
GIFT CARI
: toSK«KM(fl«fw«fl(MKn(f«c«sa(M(M(C«>KaKßacw , (a(»a(iMc»a(Eß(Ce(S«£aicwEuM(«a(M
Pork Prose
by
Kenneth B. Kephart
ment won’t cycle as early as those
outside. Lots of studies show that,
but we don’t know why.
Light and daylength may be part
of it, but other factors seem to be
involved as well.
If you’re committed to confine
ment, then what? Light isn’t the
whole answer, but keeping gilts
out of the daik will help.
For example, experiments at
lowa State and in Canada show
that gilts in total darkness will be
slower coming into heat than those
getting artificial light or natural
light through windows.
How many hours of light are
needed? Experiments point to 6 to
8 hours as an absolute minimum.
And studies at Purdue make a
15-hour schedule look pretty good
especially during late summer
and fall when day length is
waning.
From August to January, gilts
getting IS hours of light (8 hrs
natural, 7 hrs artificial) cycled an
average of 20 days earlier than
those on natural light alone.
Developing Boars
Light does influence the time it
takes for boars to reach sexual
maturity. But the details are a little
different from what we described
for the gilts. With the male, it
doesn’t seem to matter whether
'X.
or
Mall Thli
LANCASTER FARMING
P.O. BOX 609
EPHRATA, PA 17522
Subscriptions Will Begin
With Christmas Issue
NEW RENEWAL
STATI
COUNTY
days arc getting longer or shorter.
If the daylight is short, supplemen
tal light will accelerate mating
behavior.
Studies at Purdue show that IS
hours of light (8 hrs natural, 7 hrs
artificial) will increase libido
scores in young boars.
Unfortunately, these boar
experiments are a little misleading.
For one thing, only crossbred
boars were used. Many commer
cial producers use purebred boars.
Secondly, libido scores were taken
from about 5 to 8 months of age—
too early to be using boars in the
first place.
Lactating Sows
Only a few studies have mea
sured the effect of light on lacta
tion. But the results are striking.
For example, at Kansas State,
sows getting supplemental light
weaned liters that were 6 pounds
heavier at 25 days than those
exposed to lights only at feeding
time. And by S days post weaning,
83 percent of the sows in the light
ed group were in heat, compared to
only 68 percent in the dark group.
In a University of Georgia
experiment, sows receiving 16
hours of light weaned .9 more pigs
and litters that were 10 pounds
heavier at three weeks compared to
sows on eight hours of light. Survi
val of all pigs weighing 3 pounds
and under at birth was improved.
How Does It Work?
We haven’t answered that one
yet Study after study shows that
light has no influence on the hor
mones crucial to reproduction.
About all we know is that the more
time a pig spends in the dark, the
heavier his pineal gland becomes.
(This is a tiny structure in the brain
that starts out as a third eye in the
t
m To
fetus, but ends up as a pineal with
nerve connections to the functional
eyes.)
Recommendations
We don’t have all the answers,
but here are some suggestions:
• Growing-finishing hogs. If
you have hogs in dark confinement
buildings, lights should be on a
minimum of 8 hours a day.
• Developing gills. From about
August until January, gilts cycle
earlier with 16 hours of light. If
you have ample light coming
through windows or curtains the
rest of the year, that’ll be adequate.
If gilts are housed with the other
market hogs, then the finishing
floor should have 16 hours of light
during late summer and fall.
• Developing boars. Sixteen
hours seem to provide the best
response for very young boars. But
as long as boars are getting 8 hours
throughout the growth period,
that’ll probably be adequate for
practical situations.
• Lactating sows. Provide 16
hours.
Shorthorn Futurity
LOUISVILLE, Ky. The
Ninth American Shorthorn Heifer
Calf Futurity Show was held in
conjunction with the North Ameri
can International Livestock
Exposition in Louisville, Ky.
The Futurity Show was one of
the beef highlights of the NAILE.
In futurity contests, all the entry
money is awarded back to winners
in each of the three classes.
Class I, the oldest calf heifers,
awarded six places. Class n, the
second oldest, awarded six places.
Class 111, the youngest, awarded
three places. 1
Ten judges were selected by the
futurity committee. Each judge
was given birthdate, weight, and
frame score information for each
of the IS calf heifers. .
- X
Each Shorthorn heifer calf in the
Futurity carries the genetic blood
lines of the breed’s leaders, in the
desired performance traits, in
many categories, according to Dr.
YOUR WORK CLOTHES HEADQUARTERS
Lancaster Farming Saturday, December 7,1991-D3
How Long?
How Bright?
Light coming from fixtures cov
ered with dust and fly specs will
not be enough. Light coming
through fan blades will not be
enough. Light coming from heat
lamps in the farrowing house will
not be enough.
Most experiments indicate 300
to 400 lux is optimum. To be sure
what you have, measure the inten
sity about one foot off the floor.
Otherwise, a rough rule of thumb
is that one ISO-watt incandescent
bulb will provide about 300 lux
over 100 square foot area (about
the same area as three farrowing
crates). One 40-watt fluorescent
bulb will do about the same.
And keep in mind that lights in
the farrowing house should be
installed over or behind the sows
head so the front of the crate
doesn’t create an obstruction.
What Kind?
It doesn’t matter. Incandescent
or fluorescent will work equally as
well. But remember, fluorescent
lights provide more light, watt for
watt, than incandescent.
Roger E. Hunsley, executive sec
retary of the American Shorthorn
Association.
"We buy the best females we
can afford and perform embryo
transplants. The best way to have a
national champion is to use
embryo transplants. If you are not
in the business of doing trans
plants. you simply can’t compete
with the best of the breeds," said
Ralph Ramsey, a competitor from
Greenfield, Ind.
After judgements were made,
the IS shorthorn heifer calves were
auctioned off to the highest bidder*
"These breeds have contributed
to the genetic pool of excellence
across the country. You can count
on these breeders,” said Dr.
Hunsley.
The top seller was a heifer out of
Allerton, 111., Riola Star Baby ET,
weighing 770 pounds. She was
calved September 16, 1990 arid
sold for $5,000.