wjfjP P® Prose
3F*
•> /
Seeing the 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 in
tensity is best. So I took a look at
the research conducted 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 fin
ding. When pigs are raised in
complete darkness, weight gains
are depressed. And conversely,
providing 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
totally enclosed buildings, leaving
the lights on during working hours
makes good sense.
DEVELOPING GILTS
One thing is pretty certain
regarding gilts - those in con
finement 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 in
volved as well.
If you’re committed to con
finement, then what? Light isn’t
the whole answer but keeping gilts
out of the dark will help. For
example, experiments at lowa
New Jersey showmanship champs
Dr. Robert Herr, of Nix Besser Farm, Narvon, Pa., judged
the 4-H Livestock Show at the Cumberland County Fair in
Millville, NJ, on July 10.
Dr. Herr is flanked by Michelle Ayars, winner of the beef
showmanship contest, and lamb showmanship winner David
Dilks. This year’s 4-H beef, sheep and hog shows were double
the size of last year’s events.
Kenneth B. Kephart
Extension Swine Specialist
Pennsylvania State
University
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 daylength is waning.
From August to January, gilts
getting 15 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 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 days are getting longer or
shorter. If the daylength is short,
supplemental light will accelerate
mating behavoir. Studies at
Purdue show that 15 hours of light
(8 hrs. natural, 7 hrs. artificial)
will increase libido scores in young
boars.
Unfortunately these boar ex
periments are a little misleading.
For one thing, only crossbred
boars were used. Many com
mercial 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.
LACTATINGSDWS
Only a few studies have
measured the effect of light on
lactation. But the results are
striking. For example at Kansas
State, sows getting supplemental
light weaned litters that were 6
pounds heavier at 25 days than
those exposed to lights only at
feeding time. And by 5 days post
weaning, 83 percent of the sows in
the lighted group were in heat
compared to only 68 percent in the
dark group.
In a University of Georgia ex
periment, 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. Survival 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
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.
1. Growing-finishing hogs: If you
have hogs in dark confinement
buildings, lights should be on a
minimum of 8 hours a day.
2. Developing gilts: 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.
3. 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.
4. Lactating sows: Provide 16
hours.
How Bright?
Light coming from fixtures
covered 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 in
tensity about one foot off the floor.
Otherwise, a rough rule of thumb is
that three clean 100-watt in
candescent bulbs will provide
about 300 lux over a 75 square foot
area. Two 40-watt flourescent
bulbs 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
of flourescent will work equally as
well. But remember, flourescent
lights provide more light, watt for
watt, than incandescent.
Indiana girl repeats
Simmental Summer Classic win
BOZEMAN, Mont. - Nikki
Overpeck of Clinton, Ind., was the
high scoring individual for the
second consecutive year at the
American Simmental
Association’s Fifth Annual
Summer Classic, held recently in
Lincoln, Neb. The team com
petition was won by a group of four
from Texas.
More than 200 junior members,
representing 19 states competed in
a Sire Selector exam, Herdsman
quiz, Public Speaking, Heifer Sales
Talk, Beef Bowl, Livestock
Judging with Oral Reasons, a
Heifer Competition and
Showmanship.
“Emphasis is placed on
Lancaster Fanning Saturday, July 20,1985-D3
Bedford show
(Continued from Page D 22)
Williamsburg, Bedford and
Northern Bedford FFA chapters.
The sale’s 103 hogs averaged 216
pounds, and went for a total of
$16,163.51. The average price,
including champions was $72.53
per pound.
Serving as show judge was
Hatfield Packing buyer Ezra
-Good.
Buyers who contributed to the
sale’s success included Hatfield
Packing, Rhodes Meat Market,
Shaw Packing Co., Tri-County
Packing Co. A.J. Peachy Meat
Market, Farmers Livestock
Market, Jacob Dressier, Morisson
Cove Livestock Market. Indiana
Lehigh Judging Contest Winners
9, saw 64 4-H'ers from seven counties in competition. Pic
tured above is the winning senior team from York County.
From left are Joann Rishel, Jamie Kohr and Krista Rankin.
Miss Kohr was also the high scoring senior individual.
m
From Berks County, the top junior team included Glenn
Heffner (high scoring junior), Jane Zook and Valerie Hunter.
Judges for the contest were Scott Davenport, West Grove;
David Albert, Trout Run; and David Hartman. Turbotville.
E. Natl to include ewe sale
TIMONIUM, Md. - An added
feature of interest to purebred
sheep breeders at this year’s
Eastern National Livestock Show
will be a yearling ewe and ewe
lamb sale. This year’s ENLS will
be held October 2 to 5 at the
education, competition, par
ticipation and recognition at the
Summer Classic”, said Earl B.
Peterson, ASA executive vice
president. “In keeping with ASA’s
performance philosophy, the
Classic is most of all, a learning
experience for our junior mem
bers”.
The Texas I team, composed of
Whitney Rismger of San Antonio;
Donnell Brown, Throckmorton;
Lucy Jo Buxkemper, Ballinger;
and Greg Chovanec of Caldwell
bettered all other teams in
cumulative event scores. The
runner-up team was Kentucky I;
followed in order by Maryland I;
Montana; and Indiana.
Livestock Market, Blair-Bedford
Buying Station, Rendulic Packing
Co., Greencastle Livestock
Market, John Diehl and Alfery
Sausage Co.
Heavyweight
1. Sheila Biddle; 2. John Dowey;
3. John Bechtel.
Light Heavyweight
1. Kevin Rhodes; 2. Gina Hall; 3.
Carol Frederick.
Medium Weights
1. Kevin Dowey; 2. Fred Dixon;
3. Melvin Leach.
Light Weights
1. Robbie Anderson; 2. Todd
Hall; 3. Ed Clark.
Maryland State Fairgrounds in
Timoniuni. The sale is scheduled
for 2:00 p.m. Saturday, Oct. 5.
The sheep show at the 1984 ENLS
was the largest of the three species
of livestock on exhibit at the
prestigious show. Plans are to
continue this trend by using strong
publicity and maintaining high
premiums.
Plans have been finalized by a
committee of representatives from
Maryland’s three purebred breed
associations who are working
closely with ENLS manager Ken
Shifflet to promote and coordinate
the sale. Initial plans are to include
the Dorset, Hampshire, and Suf
fork breeds, with the possible
addition of other breeds, in future
years. Classes will include
yearling ewe, fall ewe and ewe
lambs. Trophies will be presented
to the champion and reserve
champion sale ewe in each breed.
For information and entry
blanks contact the ENLS, Box 38,
West Friendship, MD. 21794. 301-
442-5712.