Passage-free penning
The idea of making every square foot count in pig fattening buildings has led to a new design concept by British turnkey housing supplier A.M. Warkup.The Warkup hog feeding house has no passages inside the building. Each pen holds up to 50 hogs from 55 pounds to slaughter at up to 242 pounds. Feeders are automatically filled from external bins just as in a conventional poultry broiler house. Other ideas from the booming broiler production world have also been incorporated.
"We're going for big [pig] groups, with 50, 60 or even 100 feeding hogs in every pen and we're judging the efficiency of our houses, not on the number of pigs housed but on the weight of pork produced per square yard," says Warkup technical sales manager Simon Grey.
Also as in broiler houses, wood is used for side walls - prefabricated pressed plywood panels sandwiching thick insulation material. Ventilation, though, is natural and controlled via a unique roller-curtain system covering the open upper half of the side walls. The heavy-duty plastic curtains are mounted on rollers on top of the side-walls. Climate control can be manual or else thermostat-steered with pulleys raising or lowering the curtains according to the temperature within the house. "With curtains closing upwards from a bottom roller, the system is much better at conserving heat and cutting draughts during cold weather," explains Grey.
Another plus point underlined by the Warkup experience so far is the lack of bullying and aggressive behaviour in big groups of feeding pigs. "With large numbers like this in single pens we've found there's more chance for single members of the group to keep out of the way of the more aggressive types," Grey says. This positive aspect of large group housing is also being reported currently by researchers comparing aggression within members of small and large groups of dry sows.
"Because of our simple design with all space devoted to hogs, building costs are at least half those of conventional buildings," he adds. "Housing per pig going through the system is now down to £3, or C$7, with 0.5 square metres per animal."
This fall, Warkup has completed a demonstration unit for its new design concept in Germany, with 15 fully slatted pens each for 50 hogs under one roof. Total capital cost in this case came to C$1,750 per pig place. Grey says that similar Warkup sheds in England built for large-scale farrow-to-finish enterprises are being divided into four pig pens for hogs from 66 pounds through to slaughter. The four pens are all for one batch farrowing in most cases, with the hogs equally divided and penned male and female of average weight and above, and the same for those below the average.
The simple slatted Warkup system is attracting a lot of attention because it offers an escape from the straw-litter fattening houses that many pig producers have adopted because of demand for hogs raised in "animal welfare" systems - housing based on straw bedding instead of slats. Last year, not only did the prices for straw-system pigs sink just as low as for any other sort, but a wet cereal harvest throughout most of Europe made dry baled straw a very scarce - and expensive - item.
For more information: A.M. Warkup, Aerodrome Works, Lisset, Driffield East Yorks., Y025 8PT. U.K. Tel. 011 44 1262 46 86 66; fax 011 44 1262 46 86 56
© copyright 1999 Agricultural Publishing Company Limited.
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Slats give pig pedicure
European hog feeders now have the choice of conventional concrete slatted floors for heavy slaughter animals or lighter, warmer, non-corrosive and easier to clean slats made of plastic. Thanks to a new design in glass fibre supports, plastic slats can for the first time bear the weight of pen-loads of 240-pound slaughter hogs.Behind, or rather below, this innovation are extra-strong 120- to 150 mm-deep hollow-section slat supports on 80-cm centres. Price of the plastic flooring, which features efficient self-cleaning slat gaps of 14mm, runs about C$60 per square metre.
There's one major drawback with plastic slats for slaughter hog systems, though - they're actually too easy on the trotters. Slat designer Heinrich Michel points out that the slaughter hogs' hooves grow too fast and make for feet troubles when there's no natural abrasion such as the continual wear and tear from concrete slats or solid flooring.
This German inventor's answer has been plastic flooring, with between 15 and 20 per cent of the pen area made up of slat panels which have mineral sand cemented onto the upper surfaces. These rough areas help keep the hogs' hooves in order and are positioned in the most-travelled areas such as in front of the feeding trough and around the drinking nipples.
Michel points out that the cementing of the sand onto the plastic was one of the most difficult aspects of the development and it took him almost 10 years to get a substance that made for a long-lasting adhesion. The special cement has now proven in extensive trials to withstand regular high-pressure water jet cleaning. - Norman Dunn
For more information: MIK Germany, Marienstr 4, 56269 Marienhausen, Germany Tel. 011 49 2689 94 36 21; fax 011 49 2689 94 36 40; email mik@mik-online.de
© copyright 1999 Agricultural Publishing Company Limited.
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Maximize the male effect
It is now 30 years since I had a coffee break conversation about the "Whitten" and "Bruce" effects in mice with colleagues in the physiology department at the University of Nottingham.It so happened that I was examining data on puberty attainment from gilts that I had on experiment that day. On returning to my desk I found myself asking whether the differences in pubertal age that I was trying to explain were due to the extent of contact that they had had with boars in the unit. Analysis of the data soon showed a clear relationship, and when we published the data the following year, the concept of "male effect" in gilts entered the public domain.
As a result of the work we did back then our recommendations to producers were:
* Gilts that were intended as breeding herd replacements should be reared in isolation from boars
* Gilts should be introduced to boars for the first time at around 160 days of age
* Mature boars and preferably a rotation of boars should be used to enhance the stimulatory effect
Thirty years on, how would the vast amount of research that has since been undertaken on this topic alter the recommendations we should give to producers today?
Rearing environment
Rearing gilts in environmentally controlled housing has been reported to delay the onset of estrus. Until recently, it has been accepted that the gilt needed to accumulate a certain level of body fat before she was able to attain puberty. As increasing stocking density generally reduces growth rate and hence the accumulation of body fat, this was assumed to explain why confined, tightly stocked gilts tended to reach puberty later.In some recent Australian studies, however, space restriction that was sufficient to reduce growth rates during rearing did not increase age at puberty in gilts exposed to boars from 160 days of age.
Canadian studies have suggested that protein growth rate rather than fat content may be more important than previously appreciated. When gilts were grown at their maximal protein deposition rates and the fat growth was varied, it was found that fat content had no effect on sexual development. Thus we must look for alternative explanations for the observed effects of housing. Three candidates are worth mentioning: season/photoperiod, the impact of the gaseous environment and the environment in which the gilt has contact with the boar.
Season/photoperiod
Although the domestic pig has lost a lot of its seasonality, it has not disappeared completely. Consequently, both season and climatic conditions have an effect on the reproductive performance.Although gilts tend to be more responsive to the male effect in the winter months, surprisingly little work has been undertaken on the effect of photoperiod. Increasing the length of the photoperiod to 15 hours during the period of reducing day length (August to January) has been shown to reduce average age at puberty by 20 days. Supplemental lighting in the period of increasing day length, however, had no effect on pubertal age. There is little work on which to propose suitable light intensities for the housing for prepubertal gilts, other than one small study which found no advantage in increasing intensity beyond 90 lux.
Gaseous environment
There is some limited evidence that the gaseous environment may affect puberty attainment in gilts. Ammonia concentrations as low as 20 ppm in environmentally controlled buildings have resulted in a reduction in the proportion of pigs reaching puberty.In a controlled study, the proportion of gilts that attained puberty within seven and 10 days of boar exposure was significantly higher when they were reared in a "clean" environment (slurry channels flushed with water twice weekly) than a "control" facility in which the manure was allowed to accumulate.
The study suggests that the presence of high levels of odorous gases such as ammonia may interfere with pheromone reception by the gilt and hence block the male effect on puberty.
Contact environment
The environment in which boars and gilts meet can affect the behavioural interactions between them. For effective boar stimulation to occur, the boar must be able to access all the gilts in the group and interact snout-to-snout with them. He must have sufficient time to interact with all the females in the group; and sufficient space for effective interaction.The time that the boar is allowed to spend with the gilts, the size of the gilt group and stocking density will all affect the stimulus provided by the male. The study conducted in Australia by Paul Hughes provides some interesting insights. In his study the boar exposure groups comprised two, four or eight gilts that were exposed to the boar for five, 12.5 or 20 minutes per day in either a small (11.1 m2) or a large (22.2 m2) exposure pen. The results of this study show a clear effect both of duration of contact and the number of gilts in the group, but not size of the exposure pen on pubertal age, or the proportion of gilts reaching puberty. See The boar effect.
Furthermore, there was a significant interaction between duration of exposure and the number of gilts in the group and days taken to reach puberty following the start of treatment.
Professor Peter Brooks is with the
Seale-Hayne Faculty of Agriculture, Food and Land Use, University
of
Plymouth. U.K.
© copyright 1999 Agricultural Publishing Company Limited.
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Gilt-friendly your barn
Here are my recommendations for maximizing the male effect on puberty 30 years on: Gilts' rearing environment* Avoid stocking densities that result in reduced growth rate and most particularly reduced protein growth
* Reduce the levels of noxious manure gases
* Provide supplementary lighting during periods of declining day length
* Rear gilts, if desired, with littermate males but don't mix them with novel males late in the rearing phase as this may pre-empt the planned response to the male effect
Managing the male effect
* While gilts are capable of responding to the male effect from 140-190 days of age, the most synchronous response still appears to be achieved when they are exposed to boars for the first time between 160 and 170 days of age
* Relocation of the gilts at the commencement of exposure is beneficial and is essential when gilts have been reared with boars or have had fenceline contact with boars during the prepubertal period
* Use novel boars as stimulus boars
* The stimulus boar(s) should be at least nine months of age and have a high libido. Note: Physically large boars may be advantageous initially as their stature evokes a different behavioural response in the gilts
* Introduction of large estrus females into the gilt group may enhance puberty attainment
Contact environment
* The male effect requires intimate physical (not fenceline) contact between gilts and the stimulant boar
* For an individual boar-gilt interaction 10-15 minutes per day may be adequate. Increase interaction times as group size increases or if distractions occur
* Enhance pubertal response by moving the gilts to the boar rather than bringing the boar to the gilts
* Aim for frequent (two or three times per day) contact
* Group size should be minimized to ensure intimate snout-to snout contact occurs between the boar and all gilts
© copyright 1999 Agricultural Publishing Company Limited.
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