Mechanical transmission of porcine reproductive and respiratory syndrome virus throughout a coordinated sequence of events during cold weather

Posted in: Air Filtration, Pork Insight Articles by admin on August 27, 2002 | No Comments

A field based model was used to assess the mechanical transmission of PRRS . The model involved a replica of a common farm workers behavior during cold weather, below 0^o C. The model used common fomites (boots and containers), vehicle sanitation, transport and the movement of the workers to track the spreading of PRRS. A strain of PRRS was put into carriers that were made up of water and snow and then put on the undercarriage of a truck. The truck then drove 50km to a truck was where the drivers boot came into contact with the carriers. Then the truck was driven another 50km to a simulated farm where the drive walked around and mechanically spread the virus in the anteroom. From there, common containers made contact with the floor drippings. Then all the pieces that came into contact with the carriers were sampled to track the spreading of the virus. This was replicated ten times. At several sampling points PRRS virus nucleic acid was detected in 8 of 10 replicates. In each of the 8 samples that did test PRRS positive infectious PRRS was detected on the surfaces of containers. All the control (non-inoculated) tests found no sign of PRRS. Leading researcher to believe that  mechanical transmission of PRRS can occur during coordinated sequence of events is cold weather.

PRRS virus area spread and aerobiology

Posted in: Air Filtration, Pork Insight Articles by admin on August 23, 2002 | No Comments

The disease PRRS has long been a problem faced by pork producers. The disease reduces productivity of the swine herd, and costs are spent on preventing and treating the disease, both of these factors cut into producer profits. The elimination of PRRS from a swine herd is only a temporary solution as the disease is almost always is able to penetrates swine dense areas, even with tightening and improving bio-security measures. Despite the impact of the disease, little is known about how it is spread and how it can be prevented. Aerosol transmission is said to be the way the disease travels, but this has never been backed with any empirical evidence. This paper attempts to show how breaking down the spread of the PRRS virus into smaller parts can make it easier to understand. It is suggested that to understand PRRS movement, we must first learn: Number of organisms aerosolzed by an infected pig over units of time, the rate of inactivation of airborne organisms under specific environmental conditions: temperature, light, relative humidity, dust, etc, the rate of dispersion of infectious particulates and direction of air flow, and the number of viable organisms required to infect the next susceptible pig. These factors are quantitative values making estimations possible although some of the data required must still be obtained. This information can be crucial, if a disease begins to spread predictions can be made about its range and preventive actions  can be taken.

Measurement and Analysis of Dust Spatial Distribution in a Mechanically Ventilated Pig Building

Posted in: Environment by admin on July 28, 2002 | No Comments

Dust has been implicated as a major contributor to the increased incidence of respiratory disorders among pig workers. Unlike gaseous contaminants, dust is not uniformly distributed within pig buildings. Dust spatial distribution is an important variable in the understanding of dust transportation and the implementation of appropriate control strategies. There is a lack of data on dust spatial distribution in livestock con”nement buildings because of a lack of adequate sampling techniques. In this project, a multi-point sampler was used to measure the dust spatial distribution in a mechanically ventilated pig building. Experimental results show that there was a high variation in the dust spatial distribution within the mechanically ventilated pig building. Ventilation rate and diurnal change of weather a!ect the dust spatial distribution. It was shown that dust source control such as oil sprinkling at regular frequencies was an e!ective measure to control the dust levels. Room air cleaning such as dedusters can be used to reduce dust concentration and change dust spatial distribution.

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AVERSION OF PIGS AND DOMESTIC FOWL TO ATMOSPHERIC AMMONIA

Posted in: Welfare by admin on January 1, 2002 | No Comments

Survival Rate May be Heritable

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An average 7% of piglets are stillborn and around 13% of live born piglets die before weaning, according to Dutch researchers, who add that genetics may be partly to blame. Half the variation in backfat is heritable, for example, and easy to measure. Survivability is more complicated. In 1993, the breeding company Topigs began collecting data to find if genetic differences in survival exist between families. The protocol includes individual identification of all piglets at birth, even stillborns. All piglets are weighed and cross fostering registered. The current data set includes records of 600,000 piglets. An analysis showed heritability of survival on a piglet basis was around 0.02, which can be considered very low.However, given the fact the chance variation is very high a

Day-time time budgets of pregnant mares housed in tie stalls: a comparison of draft versus light mares

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Large differences in the amount of time a confined animal engages in behavioural activities (time budgets) compared to feral or wild conspecifics has been used as a measure of poor welfare. In the present study, day-time (08.30-05.30 h) time budgets were generated from 55 light and 55 draft late pregnancy mares housed in tie stalls from ten pregnant mares’ urine (PMU) farms using continuous video recording. Equal numbers of light and draft mares were filmed on each farm during the months of February and early March. The actions recorded included eating, drinking, resting (standing and recumbent), standing active, and interactions between horses (aggressive and non-aggressive). In addition to this, the presence and duration of stereotypic behaviours such a cribbing, head bobbing, weaving, and wood/bar chewing were recorded. Light mares spent significantly more time feeding and significantly less time standing active and standing resting. However, the time budget of both groups fell within the range of previously published activity budgets of feral horses. Therefore, the differences noted may not be clinically relevant. Three light and two draft mares performed repetitive behaviours at a level that is considered stereotypic. However, there was no difference in the number of horses performing stereotypies between light and draft mares. Because of the overall low prevalence of stereotypies and the fact that time budgets were similar to free-range horses, we believe that the management practice of keeping large number of pregnant mares in tie stalls is rational and that the welfare of mares is sound.

The provision of drinking water to veal calves: II. Behavior, physiology, and abomasal damage.

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This study examined the impact that the addition of roughage in the form of wheat straw or beet pulp to the standard diet of milk replacer to veal calves. This study examined the impacts forage inclusion in the diet would have on stress and welfare. The control animals were only fed milk replacer. The control calves performed more abnormal oral behaviours around meal times. Initially calves fed solid fed, demonstrated more chewing behaviours but the control calves were chewing at the same level as calves given straw by week 13 and those given beet pulp by week 17. The frequency of cross-suckling was low, it was most commonly observed at meal times. However, the provision of roughage did not affect the performance of cross-suckling. Offering roughage did not impact self-grooming and was not related to rumen hairballs. The control animals spent more time in contact with the milk bucket, while wheat straw fed calves spent more time in contact with the feed trough. There were not any significant differences in the cortisol levels amongst the treatments. The beet pulp fed calves had higher white blood cell count, neutrophil/lymphocyte ratio and sodium levels and lower platelet counts, which may be due to the increase in iron intake. Calves that consumed either form of solid feed had a higher incidence of abomasal ulcers and erosion, but the effects were more prominent in the calves fed straw. Therefore, the two forms of roughage were able to satisfy the calves’ behavioural needs, but it still damaged the digestive tract. Therefore, more research is needed to discover a roughage source that improves the welfare of the animal without harming the digestive tract.

Behavioural, health and cortisol responses of young calves to tail docking using a rubber ring or docking iron.

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In some areas of the world, tail docking dairy cattle is a common procedure. The typical method is to use a rubber ring. The belief is that this procedure improves hygiene and reduces the risk of mastitis; however, this is not supported by scientific research. The current study was conducted to compare the responses of calves that were either tail docked using a rubber ring or a docking iron. A control group was also included, which were exposed to same restraint, but were not tail docked. The results indicated that tail grooming increased up to five days after the rubber ring was applied. The calves with the rubber ring also had a higher frequency and shorter bouts of standing and lying than the calves that were docked with an iron and the control group. Other than one hour after the rubber ring was applied, where these calves had a significantly higher cortisol concentration than the control group, cortisol responses and other behavioural responses of pain (including vocalizations) did not differ among the groups. There were no differences in behaviour between the control group and iron-docked group. Milk intake, weight gain, body temperature and feces score (degree of diarrhoea/blood) did not differ among the groups. In conclusion, using rubber rings for tail docking did not result in a greater behavioural and physiological response than docking with a docking iron. The authors point out that the long-term effects need to be investigated.

Uterine capacity in the pig reflects a combination of uterine environment and conceptus genotype effects

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Weaning Weight Variation and New Approaches to Feeding Gestating Sows

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Gestation feeding programs should ensure that sows are at the proper body condition score at farrowing, reproductive performance is maximized, and nutrient requirements are met at the lowest cost. Back fat is the most important aspect of condition. Too little back fat reserves can reduce reproductive performance and increase sow mortality. Girth measurement can be used as a predictor of weight so individual sows can be fed accordingly. There are several machines available to measure back fat. Equations are then used to determine the amount of energy requirements for maintenance, maternal gain, and uterine gain. Each week, the sows back fat should be scanned and their feeders should be adjusted accordingly. Sows falling behind should be given 0.5 kg more per day of feed. On day 100, sows should be given 1 kg more feed per day for 2 weeks. Feeding according to body condition during the first 30 days of gestation is critical for minimizing embryo mortality. There is little known about feeding on days 30 to 75, but it is thought that high feed intake increased the number of secondary muscle fibers and improved growth rate and feed efficiency of the offspring during the growing period. Days 75 to 100 are important for mammary development and the sows should not be overfed to avoid over conditioning and decreasing milk yield. Feed should be increased by 1 to 2 kg from days 100 to 112 to prevent the sow’s body from deteriorating. From days 112 to 114, 2 kg or more should be fed per day to prevent the sow from going off feed.