Impact of Straw Cover on Greenhouse Gas and Odor Emissions from Manure Storage Lagoons Using a Flux Hood

Posted in: Environment by admin on January 1, 2004 | No Comments

Performance of subsurface flow constructed wetland taking pretreated swine effluent under heavy loads

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Evaluation of Phosphorus Transport in Surface Runoff from Packed Soil Boxes

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A mathematical model for designing and sizing sow farms

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Crowding effects on performance on fully and partially slatted floors

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Crowding affects the productivity of grow/finish pigs and it is generally believed that floor types differ in required space. This study was designed to determine if there is a significant interaction between the two factors. Crowding resulted in a reduction in ADG, but the type of flooring did not make a difference.

Variation: Costs and Consequences

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All-in-all-out (AIAO) systems are becoming popular in the industry. This is leading to the realization of the costs of slower growing pigs. Focus is now shifting towards total herd growth average and range in that growth. Statistically, variation can be measured by standard deviation (SD) and coefficient of variation (CV), both of which make use of the “bell curve”. The bell curve shows how many individuals are clustered around the average and how far they stray from the average (“deviate”). A narrow bell is desirable. Mean (average), median (middle observation in a range), mode (most frequent observation), minimum and maximum observations, SD, and CV are all useful in measuring variability. Measuring variation on-farm is difficult to do and the proper amount of pigs must be weighed to obtain acceptable results. The industry has developed management techniques to deal with variability such as cross fostering. Variation can affect production via sort losses, barn utilization, and effective phase feeding. Barn space is effected because faster growing pigs will go to market quicker and slower growing pigs will take several weeks longer. This will offset the flow of production. The most obvious cost of variation is in the carcass grading. In 2002, producers lost about $6.9 million based on Mitchell’s grading grid due to variability! Causes of this variation can be narrowed down to genetic and environmental. The goal of producers should be to minimize the influence of the environment on variability so that genetics is the lone contributor to variation. This description of variation can also be called “intrinsic” (factors based on the actual pig) or “extrinsic” (based on external factors such as the environment). Based on social behaviour, if average performance is good and variation low, it can be assumed that conditions are good because of little aggression. When performance drops it can be assumed that there is competition for resources such as food and water. This results in restriction of feed to some pigs, which will likely increase the variability. When variation in a facility is relatively low, management is the best key to handling it. If variation is high then it should be looked at to reduce variability. Reasonable CV targets are 20% weaning weights, 12 to 15% nursery exit weights and 8 to 12% for weight at first pull. If the CV is above target, look at reducing variability. If it is on target, work on managing the variability.

Impact of speed of growth and slaughter weight of pigs on performances, carcass and meat quality, and organoleptic properties of meat

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In Québec, pigs are slaughtered at an average weight of 107kg, but the market tends to seek heavier pigs. Two proofs were conducted to evaluate the impact of speed of growth and slaughter weight of commercial pigs (107, 115 and 125kg). It has been found that increasing slaughter weight reduced feed conversion, daily gain and the soluble collagen content but increased back fat and muscle thickness as well as carcass yield and loin eye area. Pigs born from fathers with GPI contributing to faster growth did grow faster and eat more each day, but their feed conversion and other zootechnical performances were not significantly affected. It also been found that slow-growing pigs had larger proportions of leg (primal and commercial cuts), primal shoulder (Boston) butt and commercial loin and a firmness of meat slightly higher. Speed of growth had no impact on number or size of fibers. As well, slaughter weight did not influence the number of muscle fibers, but pigs slaughtered at 107kg had shorter fibers. The meat of the pigs slaughtered at 107kg contained less protein. Faster growing pigs showed a larger belly, which had a lower “iodine” index, and acquired more fat and less muscle. As far as pigs slaughtered at 125kg are concerned, they exhibited a larger shoulder butt proportion, a higher-scored loin colour and a slightly higher firmness of meat. Our model showed that slaughter weight affected farm profitability, depending on various factors. Overall, neither increased slaughter weight nor faster growth had any major negative impact on meat quality.

Behavioural, endocrine and immune consequences of mixing in weaned piglets.

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Weaning often combines several stressful events such as sudden change of diet and mixing with unfamiliar piglets. These sudden changes induce behavioural, endocrine and immune alterations and are followed by a transient reduction of growth and digestive disorders. At weaning, the physiological effects of social reorganization could be masked by the much more important effects of the diet change. The aim of this study was to evaluate the reactivity of piglets to mixing by dissociating social reorganization from weaning itself. This study investigated the influence of mixing five days after weaning, when most of the acute physiological adjustments of weaning have disappeared. The response to mixing was assessed by measuring salivary cortisol, blood lymphocyte proliferation, interferon- production and behavioural activity. Cortisol levels were increased after mixing and returned to basal values within 24h and the blood lymphocyte level was not affected by mixing. Mixing increased resting behaviour. Piglets seemed to avoid conflicting encounters by diminishing the synchronization of their activities with their new group. The results of this study show that mixing young piglets is stressful but that animals develop behavioural strategies to adapt to the situation.

Effect of increased floor space on aggressive behaviour in male turkeys (Meleagris gallopavo)

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Turkey production in recent years has become very competitive and highly specialized. Fast-growing strains of turkey broilers are usually housed in large buildings, which may contain 1000-25,000 birds at stocking densities up to 60 kg/m2. Under commercial rearing conditions, domestic turkeys are often aggressive towards ‘pen-mates’, and this may lead to serious injuries or even death. Restricted space, as a consequence of high stocking density might prevent the attacked bird from retreating from its opponent. This study examined the aggressive response in 10 groups of five familiar turkey toms, comparing behaviour to an unfamiliar conspecific that is introduced to two pens of different sizes. Groups were tested both in small and in a large pen for 30 min. In the small pen they observed significantly more aggressive pecks and threats to the introduced bird. In the larger pen introduced birds kept a greater distance from the group than in the small pen. The mean number of fights and chases per test was not different between the two pens. In summary the present study shows that in small groups of turkeys, an increase in floor space reduces the number of aggressive pecks and threats aimed at an introduced unfamiliar conspecific. It is concluded that one of the reasons for high injury rates in fattening turkey toms reared under commercial breeding conditions might be the restricted space due to high stocking density which prevents the birds from moving far enough away from attacking conspecifics to avoid injuries.

Milking of Brown Swiss and Austrian Simmental cows in a herringbone parlour or an automatic milking unit.

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Automatic milking systems (AMS), consisting of one or more automatic milking units in a loose-house system, have become increasingly common in recent years. The milking process as well as the management in AMS differ from conventional systems and may influence the health and welfare of cows in various ways. For example, the daily rhythm and herd synchronization is influenced as cows in the AMS get milked singly at any time of day. In this particular study Dairy cows’ stress responses during normal successful milking in a herringbone milking parlour (HMP) were compared with their responses during normal successful voluntary milking in an automatic unit. The study used 42 cows: 12 Simmental and 11 Brown Swiss in the AMU, and 10 Simmental and 9 Brown Swiss in the HMP. After effects of milk yield, day of lactation and time of day had been taken into account, milking lasted longer in the HMP than in AMU. Location of the teats by the robot took longer in Simmental than in Brown Swiss cows. Kicking and stepping with hind legs was less frequent in the AMU than in the HMP. Brown Swiss cows stepped less than Simmental cows in the AMU. There was no difference between groups in heart rate during milking. The AMS group had higher milk cortisol values than the HMP group. This was probably not related to milking itself, but to other aspects of the system, and the absolute values were not very high. In summary, cows showed more behavioural signs of discomfort and aversion in the HMP than in the AMU. Simmental cows may be more vulnerable during milking than Brown Swiss. There were no indications of more stress in the AMU than in the HMP.