Stereotypic behaviours in sows

Posted in: Prairie Swine Centre by admin on January 1, 1995 | No Comments

Pregnant sows housed in modern production facilities often develop abnormal behaviours called stereotypies. These behaviours are characterized as regularly repeated movements that are morphologically identical and apparently useless. In sows these usually consist of oral movements such as biting and chewing directed at different parts of the animala

Separating dust particles using an aerodynamic deduster

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Dust is among the major pollutants that have a detrimental effect on the health of pigs and persons working in swine barns. Dust particles vary in size. Heavy particles settle out quickly, however, light particles remain suspended in the barn air representing a more significant threat to people and animals that inhale them. In this study, we designed and tested an aerodynamic deduster prototype that could be affixed to a recirculation duct. We also developed a particle separation theory to test the prototype based on the analysis of particle size.
Factors that affected particle separation efficiency in the aerodynamic deduster included the dedustera

Sprinkling canola oil in barn rooms

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Dust concentrations in animal buildings can be reduced by sprinkling a small quantity of canola oil. The sprinkling pressures and oil temperatures have already been defined (PSCI 1994 Annual Research Report). However, we have not yet optimized how much and how often oil was sprinkled at six application rates in three identical swine growing/finishing rooms. For the six oil application rates, dust concentration was reduced between 37% to 89%. Sprinkling more often was more effective than less often in terms of dust reduction. However, sprinkling more often than once a day is difficult when the oil application is less than 10 mL/m2 per day. Sprinkling more oil can reduce more dust, but a daily dosage of more than 10 mL/m2 caused greasy floors. Variable daily dosages for oil sprinkling had a higher efficiency of dust reduction than a constant daily dosage. A recommended variable oil sprinkling dosage is 40 mL/m2 for the first two days, 20 mL/m2 for the second two days and 5 mL/m2 for the rest of the production cycle with a 20 mL/m2 surge every two weeks. For grower/finisher units, this oil sprinkling schedule can reduce dust by 80% using only 0.5 L oil per pig marketed.

Marketing by pig or by pen

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The most common method of marketing grower-finisher pigs is to sell individual pigs that have reached a pre-set target weight that typically maximizes carcass index. However, marketing for the highest carcass index does not guarantee the highest net revenue for each hog or for the barn. For example, if no replacements are added to the pen when individual pigs are sold, the barn cannot operate at full capacity.
Marketing method can affect barn efficiency. In this study we consider two such marketing methods. The first method simply sells all pigs in the pen when the average pen weight reaches 105 kg. A second method is to market pigs individually as each pig reaches 105 kg. An extra step in the latter method is to regroup and mix the remaining pigs from several pens into a single, full pen. Pigs are often mixed and sorted in nurseries and at entry into feeder barns to maximize pig uniformity and space utilization. Mixing finisher pigs is less common because finisher pigs may fight more and experience poorer gains after mixing.
Testing new management approaches such as different marketing schemes or mixing near-market pigs is financially impractical on most farms. We have used a less costly method to test these economic effects by using a computer model to simulate these marketing schemes.

The effect of sorting grower-finisher pigs

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Sorting means mixing pigs into pens according to size and is commonly used to maximize use of barn space when feeder pigs are brought into a grower-finisher barn. Although most producers find that sorting newly-weaned pigs has little effect on productivity, sorting grower-finisher pigs can reduce gains. This is most evident if regrouping is done late in the grower period. The reason large pigs gain more slowly after sorting has been attributed to disruption of the social status within the pen. In a newly-grouped pen, aggressive, dominant pigs may interfere with feeding and drinking by subordinates. This reduces overall pen gain.

Insulin growth factor 1 in weanling-growing pigs

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Insulin-like growth factor-1 (IGF-1) is a 70 amino acid, single chain polypeptide hormone and an important regulator of cell growth and differentiation. Most fetal and adult tissues synthesize IGF-1 although the liver is the major source of IGF-1 found in the circulation. During fetal like circulating IGF-1 levels are low, however, after birth, concentrations gradually increase. Considerable evidence supports a primary role for IGF-1 in regulation of postnatal growth.
Most IGF-1 occurring in plasma and other body fluids is bound to one of 6 identified IGF binding proteins (IGFBP). These binding proteins prolong the half-life of IGF-1 in plasma and may either potentate or inhibit IGF-1 effects on body tissues. The concentration of individual IGFBPs in body fluids therefore has a significant impact on the biological activity of circulating IGF-1.
Plasma concentration of IGF-1 is mediated by a complex interaction among nutrient quantity and quality as well as other factors such as stress and disease. These factors are also likely to influence the circulating concentration of IGFBP. Knowledge of the changes in blood levels of IGF-1 and IGFBP under current swine management conditions may provide a basis to determine the impact of various management practices on piglet growth and welfare.

Vaccination against Strep. Suis

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Disease caused by infection of piglets with Streptococcus suis is responsible for some of the most significant and disturbing losses in swine production. The disease is recognized by many producers and veterinary swine specialists as the most important infectious disease currently affecting swine production in North America.
The three main objectives of this vaccine trial were to control disease in piglets by vaccinating sows in an infected herd, to determine whether vaccination alters anti-Streptococcus suis antibody titre in sow colostrums, and to compare the disease in two groups that were vaccinated with subunit bacterins to a control group. Two strains of S. suis (serotypes 3 and 9) were isolated from untreated pigs showing signs of meningitis in this herd. Two subunit vaccines (A and B) were prepared from a combination of both of these strains and were combined with adjuvant. The control group was given placebo vaccine (C ) prepared from sterile saline and adjuvant. Sows and gilts were randomly assigned to one of the three groups and were vaccinated intramuscularly at four weeks before farrowing and one week before farrowing. Barn staff recorded the identification of pigs that died and whether they showed signs of S. suis disease prior to death. The antibody titre in the colostrums of the sows that were vaccinated with vaccine A (titre of 3581) or vaccine B (titre of 1807) was significantly (P < 0.01) greater than the titre in the colostrums of the control sows (titre of 109). Likewise, piglets nursing sows vaccinated with A or B vaccines had greater antibody titres than piglets nursing control sows. The number of piglets born alive was not different among groups A, B or C, but more pigs in control group C died of S. suis disease than in vaccine groups A or B. In conclusion, both vaccine A and vaccine B reduced death from S. suis disease in litters from sows or gilts vaccinated with either of them. Both the vaccinated sows and their piglets had more antibody than controls.

Airflow pattern and contaminant distribution in swine barns

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Proper distribution of air in a ventilated barn is important in order to achieve satisfactory temperature and air quality in a swine barn. To design an effective contaminant control system in a conventional-flow type of swine barn, an understanding of airflow is most important. In this project, the FLUENT computer model was used to simulate the airflow pattern and ammonia concentration in a grower-finisher room. The predicted airflow was a three-dimensional patter. The three-dimensional flow structure, the contaminant concentration and temperature at the human breathing line (1.6 m above the flow) were highly affected by the combined jets, which were composed of a ceiling inlet, and the recirculation slot jet. The placement of the ceiling inlet and the recirculation duct affected airflow patterns, but had only a slight effect on the distribution of velocity, temperature and ammonia concentration along the human breathing line. Increasing the flow rate of cleaned recirculation airflow resulted in a lower ammonia contaminant level along the human breathing line. However, higher flow rates of cleaned recirculation air meant there would be higher fan operation and air cleaning costs. The optimum ratio of the ventilation rate tot eh cleaned recirculation rate appeared to be approximately 1:4.

Feeding the high producing sow: Estimating energy and protein requirements of the high producing sow

Posted in: Prairie Swine Centre by admin on January 1, 1994 | No Comments

A new mathematical model of particle size distribution

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Particle size distribution describes an important characteristic of airborne swine barn dust. Dust is an important component of air quality, and thus new control strategies will come from a better understanding of the particle sizes present in swine barns. This area of science uses mathematical models to aid in predicting particle size distributions under various conditions. This paper deals with the ability of the current models to accurately predict important swine barn dust characteristics, specifically particle size distribution.