Pre-dawn weaning key to conception
By TOM BUTTON
Four o'clock in the morning seems early, even on the farm. New research from Ridgetown college, however, shows it pays to get up before the sun. Pre-dawn weaning makes it much easier to manage artificially inseminated sows for top reproductive efficiency, reports Malikanthi Evans, swine researcher at the college, and one of the world's top experts on the effect of night and day cycles on pigs.
Among Evans' findings:
- Sows weaned at 4:00 a.m. come into heat within a tighter
timeframe, so the herdsman doesn't need to watch for estrus
behaviour;
- Most sows weaned at 4:00 a.m. also come into heat during the
day. By contrast, most sows weaned during the day hit their
estrus peak during the night, so artificial insemination will
likely occur several hours later than an ideal time;
- Sow herds weaned at 4:00 a.m. have excellent reproductive
success, with larger litters and minimal missed heats, if they
are routinely inseminated at 88 hours and 104 hours after
weaning.
If sows are weaned at 4:00 a.m. Monday, insemination would be scheduled for 8:00 p.m. Thursday, and 12:00 noon Friday. The findings are based on sows housed in facilities without windows, and with controlled lighting turned on at 6:00 a.m. and off at 8:00 p.m., for a 14-hour day and 10-hour night cycle.
Evans first investigated the role of light in sow reproduction with a University of Guelph study in 1994 aimed at finding the cause of late summer estrus failures, widely reported in sow herds around the world.
For decades, it was thought these reproductive losses were due to hot summer weather. The Guelph research, however, showed that the change to shorter days and longer nights was largely responsible.
Scientists had long known that daylight cycles triggered estrus in so-called seasonal breeders, such as sheep and horses, but it was assumed to play no role in species such as cattle and pigs.
Evans found the assumption was wrong. In pigs, daylight cycles may not influence the time of year when the sow comes into heat, but light certainly affects the time of day.
In brief, daytime weaning leads to nighttime estrus, which improved the odds of reproductive success in pigs before the species was domesticated.
Now, producers can turn that evolutionary trick to their own advantage by weaning at night, so sows come into heat during the day.
With help from Guelph and funding from Ontario Pork, Evans tested 49 sows at Ridgetown college, with parities ranging from one to five. Sows were kept in the 6:00 a.m. to 8:00 p.m. day cycle for one month to ensure they were acclimatized, and then were weaned, with piglets at roughly four weeks of age. The sows were split in four groups, based on time of weaning, including 4:00 a.m., 10:00 a.m., 4:00 p.m., and 10:00 p.m. weaning groups. Blood samples were collected every six hours and tested for luteinizing hormone, a compound that triggers estrus behaviours.
The results have led Evans to two key conclusions. Sows weaned during the day hit their estrus peak at night. Only the group weaned at 4:00 a.m. produced a majority of sows peaking during the day. In fact, the blood samples show that the 4:00-a.m. sows that weren't ready to peak during the forth daylight period actually skipped the night and peaked under the lights on the fifth day.
By contrast, no more than 23 per cent of sows weaned at other hours produced daytime estrus peaks.
As well, the estrus peaks for sows weaned at 4:00 a.m. were more tightly bunched together, stretching just 18 hours from the first sow to the last.
Heats for sows weaned at other hours were at least twice as protracted, and for sows weaned at 4:00 p.m., stretched over 54 hours.
Evans points out that other recent research shows that, while the industry has consistently blamed small litter sizes and low farrowing rates on the poor fertility of the sow, the actual cause is often the off timing of insemination. "With 4:00 [a.m.] weaning, we're suggesting you don't have to wait to detect estrus. You simply count the hours from weaning and then inseminate," Evans says. "You can eliminate labour-instensive estrus detection procedures, and also improve conception rates and overall reproductive performance."
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The first step is knowing the enemy
By S. ERNEST SANFORD
Events over the last year have brought our attention to a group of diseases loosely called Campylobacter Enteritis or ileitis.
For the last 20 years, ileitis has been blamed on a Campylobacter-like bacterium. After going through numerous misidentifications, however, a duo of researchers from two continents - Steven McOrist in Scotland (University of Edinburgh) and Connie Gebhart in the U.S. (University of Minnesota) - has finally nailed down the true identity of the organism causing ileitis. Although it resembles a Campylobacter, we now know that the bacterium is totally different. The name chosen for the bacterium is Lawsonia intracellularis.
Does having a name help us fight this disease any better than we were able to before? Not directly, but we certainly now have much better tools to pry the mysteries of this disease than we did previously. These new tools are already bringing instant advances in our quest to understand and control ileitis better.
The Disease
Porcine Proliferative Enteropathy, or ileitis, is a common
disease of grower and finisher pigs worldwide. It occurs under
a variety of management systems and especially in high-health
herds, including start-up and repopulated herds. It is also a
disease that could not be eradicated by Segregated Early
Weaning (SEW) techniques. Unfortunately, we can expect more
problems with ileitis as we get rid of other diseases through
SEW.
The characteristic lesion of ileitis at necropsy is marked thickening of the last section of the small or large intestines or both. Under the microscope, the inner lining of the thickened intestine proliferates almost like a cancer. Curved bacteria (Lawsonia intracellularis) are always seen inside the intestinal cells. The chronic form, Porcine Intestinal Adenomatosis, occurs in weaned pigs, six to 12 weeks old, and causes poor growth. An acute hemorrhagic form occurs in late finisher pigs, gilts and young boars. This form, Porcine Hemorrhagic Enteritis, often occurs like an epidemic with an outbreak of bloody diarrhea in replacement breeding stock or breeding animals in high health herds. One of the first advantages we have gained in having the Lawsonia organism finally identified is in diagnostics. Having an accurate identity of the bacterium has rapidly allowed us to develop diagnostic tools to know specifically if pigs carry Lawsonia. One of the confusing factors in the past had been the presence of many Campylobacters in the stool of pigs. Campylobacters are normal inhabitants of the intestines of pigs. Hence, when we went looking for Campylobacters, we found them. They are always there. Lawsonia intracellularis requires specialized cell cultures for isolation and does not grow with routine bacteriological methods. This places it beyond the capabilities of most diagnostic laboratories at this time. However, specific polymerase chain reaction (PCR) probes have been developed and are being used to identify Lawsonia in the feces of pigs. PCR is fast, specific, and not overly expensive. Many of us were first introduced to PCR technology when it was used to identify the Porcine Reproductive and Respiratory Syndrome virus two years ago.
Treatment and Control
Now that Lawsonia intracellularis has been isolated, for the
first time treatment trials with appropriate controls are
being conducted. Initial results of these trials indicate that
several antibiotics, including macrolides (eg. tylosin),
tetracyclines and pleuromulins (eg. tiamulin) are active
against Lawsonia intracellularis. It should be noted that the
above antibiotics work similarly - they enter cells and
accumulate in the cytoplasm where they are then able to attack
and kill bacteria. This is crucial since, as stated above,
this bacterium actually lives within the intestinal cells and
thus the pig's own body provides protection for the bacterium.
We will have to deal with this bug and the various diseases it
causes for some time to come. We have been relatively
successful in keeping it under control so far, but have to do
better. Now that the cause has been identified, expect better
and more specific guidelines on prevention and treatment in a
very short time, possibly even months. Our abilities to
diagnose and predict the presence of the bacterium better are
already greatly enhanced and will improve even more. Producers
can anticipate the development of vaccines in the future.
S. Ernest Sanford, DVM, is a swine specialist with Boehringer,
Ingelheim in Burlington.
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NUTRITION SUPPLEMENT
Leftovers
Tourists at a resort complex in central Florida had little
idea they were part of a pig feeding trial. Researchers at the
University of Florida in Gainesville got acceptable results
from dehydrating plate scrapings from the resort and feeding
them to pigs. The leftovers, some up to 80-per-cent moisture,
were minced, blended with a soy-hull-wheat-flour feedstock,
and dried at 150 to 200 degrees C. The so-called "dehydrated
food residual" was 11.4-per-cent moisture, 15-per-cent crude
protein, 13.8-per-cent crude fat, 10.4-per-cent crude fibre,
0.65-per-cent lysine, 0.54-per-cent calcium and 0.34-per-cent
phosphorus. Sodium and chloride (salt) levels were too high
for large amounts of the ration to be fed safely. In the
feeding trial involving 48 finishing pigs, average daily gain
for the food waste ration was similar to a corn-soybean
control diet. Feed conversion was higher, and pigs ate less of
the plate scrapings per day, evidently preferring pig food to
people food.
The bottom line
Feeding leftover food to pigs helps with disposal, and
provides an acceptable ration, but there's a caution:
extensive processing is required and salt levels may be high.
Source: American Society of Animal Science, proceedings,
University of Florida
Wheat on a roll
There's lots of feed wheat in Ontario this year. If you want
to feed it to pigs, make sure the fusarium level isn't
dangerous. And put it through a roller mill, according to
findings at Oklahoma State University. Researchers there fed
470 crossbred pigs from 18 to 100 kg the KARL-variety hard red
winter wheat, in a fine and medium grind, as well as
dry-rolled. The control was a medium-grind corn ration.
Corn-fed pigs had the highest average daily gain, 0.83 kg, and
pigs ate it in the highest quantities. But the feed-gain ratio
was the best, 2.97, in the rolled-wheat diet. Finely-ground
wheat had better feed conversion results than medium-ground.
Pigs fed the rolled-wheat diet were also the leanest, having
the least backfat.
The bottom line
If you're feeding wheat this winter, dry roll it for best
results.
Source: ASAS, Oklahoma State University
Canola can
Ontario pork farmers traditionally turn to soybeans for
protein, but feeding canola has also had good results in U.S.
trials on young pigs. Researchers at Montana State University
tried canola in the ration for 120 six-kg pigs weaned at 21
days. The pre-starter protein diet was barley-porcine-plasma,
and the starter diet was barley-soybean meal. Canola seed,
both ground and unground, was fed at four and eight per cent
of the ration. The feed was offered in meal form ad libitum,
the pre-starter fed for 14 days and the starter for 23.
Overall averages for six diets, including a simple barley and
corn-barley ration, were satisfactory, according to the
researchers. Average daily feed intake averaged 0.92 kg,
average daily gain 0.52, and feed:gain ratio 1.78. Pigs on the
high-canola ration, ground or unground, had lower average
daily gain, but both ground canola diets had better feed
conversion than unground canola diets and corn diets. The
researchers concluded that four or eight-per-cent ground
canola seed can be used in barley-based starter pig diets, and
in barley-porcine plasma protein diets; and that corn does not
improve performance in pre-starter diets.
THE BOTTOM LINE
Young pigs do well with canola in the ration as a source of
fat and protein.
Source: ASAS, Montana State University
In zinc
An extra shot of copper and zinc in the baby pig's diet can
work wonders, according to U.S. research. More than 1,100 pigs
averaging 6.45 kg and weaned at an average 22 days were given
extra copper and zinc in the diet, meeting or exceeding
National Research Council requirements. A Phase One diet was
fed for seven days, followed by a Phase Two for 21 days. Pigs
performed best on the zinc-only (3,000 ppm) and copper-only
(250 ppm) diets, versus a mixture. Pigs on the zinc gained 409
grams a day, and on the copper 399, versus 356 for the
control. Feed intake on the zinc diet (672 grams a day) and
the copper (651) both exceeded the control - 614. Feed
conversion for each diet, 1.66 and 1.65, also beat the control
- 1.74. Adding zinc or copper or both resulted in firmer
feces. Pigs fed the copper-only diet had darker feces than
pigs fed the copper-zinc.
THE BOTTOM LINE
Adding extra copper or zinc, but not both, to a weaner diet,
improves performance.
Source: ASAS
Mussel mania
At last a way to deal with those tiny zebra mussels that clog
up the lakes: feed them to pigs. Ohio State University
research trials compared using ground limestone as a calcium
source in weanling rations, to feeding cleaned, disinfected,
ground zebra mussel shells. The result? Not good for the zebra
mussels. One hundred and twenty-seven pigs housed in raised
nursery pens were fed different diets for seven days after 21
days of age. Results indicated that there were no significant
differences in pig performance for either calcium level or
source.
The bottom line
Ground zebra mussel shells are an acceptable alternate calcium
source for young pigs.
Source: ASAS, Ohio State University
Hold the vitamins
Researchers at the Prairie Swine Centre have evaluated a pig's
need for vitamins and minerals during the three to five weeks
prior to slaughter.
While making up a smaller portion of the feed bill, compared
to other components such as energy and amino acids, vitamins
and minerals still represent a significant expense. The swine
centre's John Patience and Doug Gillis divided 525 pigs, all
weighing 80 kg, into three groups. One group was fed the base
diet; a second group had vitamin and trace mineral supplements
removed for the final 17 days before marketing; a third group
had vitamins and minerals removed for the final 36 days.
In the final evaluation, the researchers concluded that the
loss of the vitamins and minerals from the diet had no
apparent effect on performance, but did impact the feed bill.
Removing the vitamins and trace minerals from the finishing
diet would save pork producers between $6 and $12 per tonne,
depending on feeding levels. Removing the trace elements for
the final 17 days would improve pig profitability by $0.46 per
pig, while removing them for the final 36 days would save
$0.98 per pig.
The bottom line
Producers can save up to $1 per pig by removing vitamins and
trace minerals from finishing diets for the final five weeks
before marketing.
Source: Prairie Swine Centre
High health, low cost
Should you feed your pigs based solely on genetic potential?
The answer is "no", says Iowa State researcher Tom Stahly and
Land O' Lakes swine technical services manager Noel Williams.
ISU research indicates that pork producers should first
consider health status when fine-tuning starter diets for
young pigs. The researchers note that complex starter diets
are formulated to maximize pig performance when the animal
faces health and environmental challenges. With the advent of
Segregated Early Weaning and all-in, all-out facilities,
disease risks are minimized, reducing the need for complex
diets. Williams says producers must first determine their
herd's health status and build a matching nutrition program.
To determine the health status of growing pigs, producers,
with help from a herd health consultant, should measure gains
and feed efficiency throughout the nursery and grow-finish
area. Establishing a proper health monitoring program requires
necropsies, serological testing and disease risk assessment.
After determining health status producers should study starter
diets focusing on ingredients feed to weaned pigs and nutrient
levels.
The bottom line
High health pigs could benefit from high nutrient levels but
also perform well when fed simpler, less-expensive diets. Pigs
in the moderate health category need complex ingredients to
fight health and environmental problems, but can prosper when
fed moderate nutrient levels.
Source Iowa State University, Hogs Today
Perfect diet
Is there a perfect diet your pigs should be on? Animal
researchers at the University of Nebraska placed crossbred
pigs on either a corn-soybean meal (intact) or corn-soybean
meal-amino acid supplemented (ideal) diet. Pigs were fed a
Phase 1 diet for four weeks until 51 kg and then switched to
Phase 2 until 95 kg market weight. In the ideal diets, protein
concentration was reduced by 4.6 per cent from the intact diet
in Phase 1 and by 4.2 per cent in Phase 2. Crystalline
amino-acids were added to the ideal diet in order to meet the
intact diet's lysine concentration. Gilts were fed ad lib
while barrows were pair fed according to the average feed
intake of the respective gilt treatment group. During Phase 1,
gilts consumed more feed and gained more weight than barrows.
Fed the ideal diet, barrows had a 14 per cent lower average
daily gain. Pigs fed the intact diet had similar gains
regardless of sex.
In Phase 2, barrows and gilts on the ideal diet consumed less
feed and had lower ADG than pigs on the intact diet. Pigs fed
the intact diet gained weight 10 per cent faster and ate six
per cent more feed than pigs in the ideal group.
The bottom line
There is no advantage in terms of daily gain and feed
efficiency of providing grow-finish pigs an ideal protein
diet. But feeding an ideal diet will reduce the amount of
nitrogen the pig wastes.
Source: University of Nebraska
Must B vitamins
Many pork producers could be overlooking one essential element
to their pigs diet: vitamins. Though they only count for 0.1
per cent of a typical ration's weight, vitamins are involved
in 100 per cent of the metabolic process enabling the animal
to turn feed into muscle, fat, skin and bones. A recent Iowa
State University study measured the rate of gain and feed
efficiency of pigs fed diets containing five B vitamins at
various levels. Diets were formulated to contain 70, 170,
270, 370, or 470 per cent of NRC requirements of the vitamins
riboflavin, niacin, pantothenic acid, B12, and folic acid. All
of the vitamins are related to muscle development. Analyzed by
genotype, one group of pigs had a high capacity to grow
muscle. The other group was more moderate in its lean growth
and muscle capacity. Pigs were fed from 8.1 kg to 34 kg and
the rate of gain was greatest at 470 and 370 per cent of NRC
requirements for the high-lean and moderate-lean growth group.
The bottom line
These results suggest as pigs increase the capacity to grow
muscle, the needs for certain vitamins are substantially
greater.
Source: Iowa State University