Manitoba Agriculture, Food and Rural Initiatives
Post Weaning Mortality in Manitoba Swine
By: Cate Dewey, Tom Johnston, Lori Oldford, Terry Whiting
The following is a report summarizing the simple associations found in the post weaning mortality study conducted in Manitoba in 1999.
Introduction
Funding Agencies:
This project is jointly funded by Manitoba Pork Council, Agri-Food Research and Development Initiative (ARDI), and Manitoba Veterinary Services Branch. Cate Dewey is employed by the University of Guelph.
Acknowledgments:
We greatly appreciate the cooperation of the swine producers and veterinarians in Manitoba who gave freely of their time for the completion of this study. We sincerely hope that the findings of this project are of interest and benefit to you. Dr. Grant Spearman and the pathologists and Dr. Gopi Nayar from the Manitoba Veterinary Services Branch deserve a great deal of thanks for the evaluation of the pigs submitted by these producers and veterinarians both historically and during this project.
Purpose:
The purposes of the study were to determine the association between nursery pig mortality and infectious diseases, management factors and circovirus.
Case versus control herds:
The project was conducted as a case control study. Case herds were those which experienced high nursery pig mortality within the past 18 months. High mortality was defined as more than 3% or a single episode where the mortality spiked above the normal herd level. Control herds were those with acceptable nursery pig mortality which for most herds was less than 3%. The herds were placed into the case and control categories by the referring veterinarian.
Farm Visits
A convenience sample of farms was selected based on recommendations by herd health veterinarians. To be included in the study the producer had to be willing to cooperate and keep records of the numbers of pigs moved into the nursery and the number of pigs that died during the nursery phase. There were 61 farms were visited between May 1 and June 30, 1999.
The producer completed a detailed survey which described the management and disease status of the herd. These were collected by Tom Johnston in a face-to-face interview. Each unit submitted three nursery pigs for complete post-mortem evaluation. All pigs were evaluated grossly and a panel of PCR tests was conducted to evaluate the presence of PRRS, circovirus, Mycoplasma hyopneumonia and swine influenza virus. Other tests such as microbiologic testing, histology, serology, and virus isolation were conducted when the pathologist believed the tests would assist with the diagnosis.
On 45% of the production units, the numbers of 5 week old nursery pigs experiencing obvious clinical problems was recorded.
Production Records
Data collected on the movement of pigs into the nursery and the nursery barn mortality varied by farm. These data were collected on farms by week, month or year or nursery fill on , 4, 15, and 8 farms respectively. There were 7 with data recorded by complete nursery barn fill. However, on 15 farms, the data was merely an estimate of the previous year’s performance.
On average, pigs remained in the nursery barn for 7 weeks. For each farm, the nursery barn mortality was converted to a 7-week adjusted mortality. The observed mortality was divided by the number of weeks that pigs were in the nursery and then multiplied by seven. This conversion assumed a consistent mortality over the entire nursery period. Although this assumption may not be accurate, the adjusted 7-week mortality was necessary for us to compare the nursery mortality across farms.
Infectious diseases:
Disease status was determined at the farm level. This was based on producer recollection, historical laboratory data, vaccination protocol, current clinical problems, and autopsy findings on the three pigs submitted during the study. If the producer believed that the herd was free of a specific disease agent but the agent had been identified on that farm by the Manitoba Veterinary Laboratory Services (MVLS) then the herd was considered positive.
Results
There were 28 case herds and 33 control herds included in the study. The case herds tended to have more sows (719) than control herds (522). There were approximately the same number of farrow-to-finish, farrow-to-feeder and off-site nursery herds in the case and control groups. The herd sizes as measured by pigs weaned per week dd not differ by case status. However, the case herds had been established for a longer time (12.9 years) than control herds (7.9 years) (P<0.05).
The relationships that were significant at P<0.10 and at P<0.05 are noted. Because of the relatively small sample size, relationships that were significant at P<0.10 and at P<0.05 were noted. Where the p-value is not indicated it is assumed to be <0.05.
Production losses in the nursery barn
The production data on 23 case herds and 21 control herds indicate that the number of pigs weaned per week and the length of time pigs stay in the nursery did not differ by herd status. However, the average mortality rate in the case herds (4.4%) was higher than the mortality rate in the control herds (1.6%) (P=0.00003). (Table 1). Case herds also had a higher proportion of poor doing pigs (3.7%) at the end of the nursery fill compared to control herds (1.7%) (P<0.05).
Abnormal clinical signs observed during 1999 herd visit
Clinical signs of disease were measured in four ways: producers were asked if they had observed specific clinical signs in nursery pigs either in the past or presently or if they had seen specific clinical signs during previous PRRS or PMWS outbreaks, the researchers observed the clinically ill pigs during the herd visit, and then the clinical problems identified in the three pigs submitted for post mortem evaluation were recorded. Clinical signs of disease were observed by Tom Johnston on 14 case and 9 control farms.
Pigs from case and control herds did not have a difference in the prevalence of general clinical signs. Joint injuries, lameness, and abscess are causing either past or current problems in 1/4 to 1/3 of the nursery units. Marked increases in culling or death occurred in 18% of the units.
PRRS
Half of the farms (68% case; 42% control) were positive for PRRS. Of these farms, case herds had been fewer months since the original diagnosis (26 mos) than control herds (41 mos) and they had been fewer months since the latest outbreak (16 mos) compared to control herds (24 mos) (P<0.05).
The clinical problems due to PRRS included sows off feed and stillbirths in 42% of farms, weak born pigs and high preweaning mortality in 50% of herds, and nursery pig mortality in 74% of case herds and 43% of control herds. Case herds had more nursery pig respiratory problems and diarrhea (74%; 63%) than control herds (36%; 14%)(P<0.05).
Only 43% of case herds and 21% of control herds used a PRRS vaccine and only 36% of control herds and 21% of case herds used the vaccine continuously. Vaccine is used in replacement gilts, open sows and lactating sows in 83, 33, and 50% of case herds respectively and 57%, 14%, and 57% of control herds.
Clinical evaluation of pigs
Clinical evaluation was conducted on only 45% of the farms due to biosecurity concerns. These herds included 13 cases and 9 controls. The most common clinical signs were difficulty breathing (puffing), pale skin, wasting and scouring (Table 2). Jaundice and coughing were rarely observed. The proportion of pale pigs in case herds (8%) tended to be higher than on control farms (4%) (P=0.06). The proportion of other clinical signs did not differ by herd category.
Of the pigs submitted for postmortem, case herd pigs were more likely to be coughing (33%) than control herd pigs (10%) (P<0.05).
Post weaning multisystemic wasting syndrome
PMWS had only been diagnosed in 2 case herds of all of the herds in the project. However, more case herds had had a diagnosis of circovirus (71%) than control herds (42%). The diagnosis was typically made by the diagnostic laboratory. Producers who believed the circovirus had caused problems identified sows off feed, (30%), increased culling (30%), diarrhea (20%), respiratory problems (41%), jaundice (15% of case herds, 0% of control herds), fading pigs (40%), pigs death (20%), increased culling and/or light pigs (38%), pale pigs (10%), low farrowing rate (5%), and sneezing (7%).
Two of the 28 case herds and none of the control herds believed that their pigs had experienced the post weaning multisystemic wasting syndrome. The diagnosis of PMWS was made by the producer due to clinical signs rather than by veterinary or laboratory diagnosis. None of the farms in the study believed that they currently were experiencing problems due to PMWS. The range of clinical signs of PMWS can be experienced by pigs due to poor management or infectious diseases.
Prevalence of disease
Producers were questioned about the disease status of their herds by etiologic agent and then information recorded in the MVLS data bank was reviewed to add to the producer recall. More case herds were positive for circovirus, enterotoxigenic E coli (Ecoli diarrhea), M hyopneumonia (enzootic pneumonia), and TGE than case herds (p<0.05) (Table 3). Case herds also tended to be more likely to have K88 Ecoli causing post weaning problems (p<0.10). Few farms were positive for A pleuropneumonia (formerly called Haemophilus pleuropneumonia), A suis, edema disease, swine dysentery or swine influenza. More case herds had nursery pigs that showed clinical signs of Ecoli K88 sudden death, enzootic pneumonia, Haemophilus parasuis (Glasser’s disease), salmonella, swine influenza, and rotavirus than control herds. The current problems in the nurseries that differed included a higher prevalence of K88 Ecoli, Staph hyicus, swine influenza and Rotavirus diarrhea in the case herds than the control herds P<0.05). Nursing pigs in case herds experienced more problems with circovirus, Ecoli diarrhea, enzootic pneumonia, Strep suis, and rotavirus in nursing pigs than in control herds.
For the three pigs submitted for post mortem evaluation, case herds were more likely to have a PCR positive circovirus test and less likely to be culture positive for E coli or salmonella than control herds (P<0.05). Common disease organisms found in at least 30% of the farms included Chlamydia, Ecoli, H parasuis, and Strep suis. The proportion of pigs with Interstitial pneumonia, colitis, and Ecoli was higher than on control herds.
On the histologic evaluation of the three pigs submitted per herd, case herds tended to have more interstitial pneumonia, colitis, enteric colibacillosis, and fewer normal pigs than control herds (P<0.10). There was only one pig with a diagnosis of PMWS and this pig came from a case herd.
Vaccination
Rotavirus vaccine was given to sows in 21% of case herds and 32% of control herds. More case herds vaccinate sows against PRRS (43%) than control herds (12%) but more control herds vaccinate nursery pigs against mycoplasma (16%) than control herds (0%) (P<0.05). Half of the herds vaccinate sows against Ecoli, 1/3 vaccinate for rotavirus and no herds used PRRS vaccine in nursing or nursery pigs. Case herds were more likely to vaccinate sows against PRRS than control herds (P<0.01).
Nursing pigs were vaccinated for mycoplasma on 5 case farms and for pasteurella on one control farm. Erysipelas was given to nursery pigs on 62% of case herds and 33% of control herds and Glassers was given to nursery pigs on one case herd and one control herd.
Case herds used the mycoplasma vaccine at a younger age than control herds (P<0.05). Other vaccines used in nursery pigs included erysipelas, pasturella and Bordetella, and H parasuis (Glasser’s disease). No farms used PRRS vaccine in nursing or nursery pigs.
Veterinary and diagnostic laboratory service
Case herds had fewer herd visits during the previous 12 month period (3.6) than control herds (6.06) (P<0.01) (Table 4). However, case herds had more veterinary laboratory submissions (7.14) during the previous year than control herds (6.06) (P<0.05). As previously mentioned, more case herds (18%) had more than six laboratory submissions in the previous 12 months than control herds (3%).
Management Factors
Nursing pig
Most piglet processing was conducted at the same piglet age in case and control herds; 1.7 days for iron and antibiotics, 4.5 days for castration, and 8 days for the second iron injection. However, case herds will foster older pigs (8.5 days) than control herds (4.7 days). Fewer control herds (42%) use routine antibiotics than case herds (68%). More control herds cross foster between farrowing rooms (82%) than case herds (61%).
The pig at weaning
Case and control herds weaned pigs at the same ages (19.5 and 19.2 days respectively) and on average did not wean below 16 days. However, case herds had a higher maximum age at weaning (25.3 days) than control herds (22.1 days) (P<0.05). Case herds also had a lower minimum weight at weaning of 4.1 kg compared to 4.6 kg in control herds (P<0.05).
In 83% of case and control herds, light weight pigs at weaning are moved into the nursery. The rest are moved into a room not ready to be weaned or put onto piggy decks. Only 3 of the case herds chose to euthanise these pigs. However for poor doing pigs, only half the farms move them into the nursery. The other farms either euthanise the pigs or move them into another farrowing room or onto piggy decks. These decisions did not differ by case herd status.
Half of the herds weaned once a week and 1/3 weaned twice a week. Most nurseries were filled from one sow herd but more case herds (18%) accepted pigs from more than two sows herds than control herds (3%) (P<0.05). In 45% of control herds, pigs are kept in litter groups in the nursery pens compared to 14% of case herds (P<0.05).
Light weight pigs at weaning are typically moved into the nursery (83%), although a few are euthanized (10%), and some are moved into a "younger" farrowing room (25%) or put onto piggy decks (15%). Poor doing pigs are also moved into the nursery (60%), euthanised (35%), moved into another farrowing room (25%) or put on piggy decks (25%).
Pig flow
A higher proportion of case herds obtain their nursery pigs from more than two sow herds than control herds (P<0.05). Control herds are more likely to move pigs from one litter into one nursery pen than case herds (P<0.05). Case herds are move likely to fill a nursery pen with pigs from one or more farrowing rooms than control farms.
Most nursery units were managed all-in / all-out by room, however 12% of the control units were all-in / all-out by barn and one unit was all-in / all-out by site. The control units were empty for 2.3 days between batches whereas the case units were only empty for 1.5 days (P<0.05).
The control nursery units were both filled and emptied in a shorter time period than the case units. It took 20 versus 11 days to fill a nursery site an 12 versus 7 days to fill a barn. Similarly, it took 12 days versus 1.2 days to empty the barn and 2.3 days versus 1.3 days to empty the room. In contrast to this, 18% of the rooms on control farms were never emptied, compared to 7% of the rooms in the case farms.
Most units managed nursery rooms all-in, all-out regardless of case category. On average it took case herds longer to fill the nursery site (20.5 days) and nursery barn (12 days) than the control herds (11.5 days and 6.75 days respectively). (P<0.05). It also took case herds longer to completely empty the barn and the room (12 days and 1.2 days) than control herds (1.2 days and 1.3 days) (P<0.05). Control herds left the barn completely empty for a longer time period (2.3 days) before refilling the barn than control herds (1.5 days) (P<0.01).
Nursery facility
The facility design of nursery barns is similar for case and control farms. The nursery units typically house 3500 pigs per year, are on one site, have 1.5 buildings per site, with 6.5 rooms per building and 14 (control) or 16 pens per room. There are 5.5 weeks of production per site and 3.5 weeks per building. On average, there were 22.5 pigs per pen, half of the units used tenderfoot flooring, 1/3 used plastic slats, and 20% of the farms had a solid concrete section on the floors. No herds in this study used bedding.
The differences in facility included weeks of production per room and space per room. However, the case herds have more weeks of production per room (1.2) than the control herds (0.96) (P<0.05). Control herds provided 3.14 sq feet per pig compared to 2.83 sq feet in case herds (P<0.10).
. There were approximately five pigs per feeder space and 17 pigs per waterer. Feed and water delivery systems did not differ between case and control herds. Half of the units used feeders and 1/3 floor fed their pigs. Chlorinated water was used in 25% and 37% of case and control herds respectively. Only 1/4 of the herds used bowl drinkers, most herds used single nipple waterers and provided one waterer per 17 pigs.
The use of husbandry techniques to assist problem pigs did not differ between case and control herds. Feeding boards, gruel feeding, electrolytes, water medication, and injection of antibiotics were routinely used in 33%, 10%, 35%, 28%, and 18% of herds respectively. These techniques were used on an as-needed basis in 20%, 18%, 22%, 50%, and 68% of herds respectively. The only difference was seen in zone heating which was always used in 25% of case herds but only in 6% of control units. In 60% to 90% of farms, zone heating and heated floors were never used in these nursery units.
Most farms sorted pigs by size into the nursery barn and approximately half of the pigs were sorted by sex. More case herds routinely used sick pens (61%) than control herds (33%), and fewer case herds never used sick pens (14%) than control herds (42%) (P<0.05).
Case herds tended to have weeks of production per nursery room (1.16 versus 0.96 weeks), fewer square feet per pig (2.83 ft2 versus 3.14 ft2), and accepted a higher maximum number of pigs per pen (25.8 pigs versus 23.6 pigs) than control herds (P<0.10).
Pig leaving the nursery
Pigs stay 68 days in the nursery, with the highest 25% of herds being 65 days and the lowest 25% of herds being 60 days. However, pigs from control herds weigh more out of the nursery (29.8 kg) than those from case herds (26 kg). Similarly, the average minimum weight of pigs out of case herds was lower (22 kg) than control herds (25.2 kg) (P<0.05).
The length of the nursery stay in case herds (67 days) did not differ from that of the control herds (69 days). Pigs from case herds tend to be lighter when leaving the nursery (26 kg) than those from control herds (29.8 kg) (P<0.10). Case herds have a lower minimum weight for pigs leaving the nursery (21.8 kg) than control herds (25.2 kg) (P<0.05). As previously mentioned, case herds have more poor doing pigs (2.7%) at the end of the nursery fill than control herds (1.5%) (P<0.05).
Pigs were weaned at 19 days but 25% of the herds weaned at 18 days or lower and 25% weaned at 21 days or higher. Case herds accepted a higher maximum weaning age (23.3 days) than control herds (21.1 days) (P<0.01). Pigs averaged 6.1 kg at weaning however, case herds accepted a lower minimum weaning weight (4.1 kg) than control herds (4.6 kg) (P<0.10).
Problem pigs
There are more poor doing pigs at the end of the nursery fill in case herds (2.7%) than in control herds (1.5%) (P<0.05). Similarly, the standard deviation for the average number of poor doing pigs was higher in case herds (2.1%) than in control herds (1.1%) indicating that there is a wider range of problems in case herds than in control herds.
Coming out of the nursery, case herds are more likely to move the pigs in with younger pigs (32%) than control herds (13%). Poor doing pigs in case herds are more often euthanised (50%) or kept in the same room (25%) than those in control herds (13%, 31%). Control herds are more likely to use a sick room (25%) than case herds (11%). (P<0.10).
Biosecurity
Case herds were geographically closer to other pig farms (2.63 km) than control herds (4.55 km)(P<0.05) and case herds had more farms within a 2 mile radius (4.11 farms) than control herds (1.12 farms)(P<0.05). All other measures used to enhance biosecurity were similar between case and control herds. Half of the herds purchased gilts from one source and most herds purchased boars from one source. Only 10 herds purchased gilts or boars from more than one source. Artificial insemination was used by all by 4 herds.
Most herds provided boots and coveralls for visitors and many herds had showers. Sixty percent of case herds and 80% of control herds provide a shower. Showers were used by all employees in approximately half of the farms. Most herds provided boots and coveralls. Most farms have a dead stock truck pick up pigs at the end of the lane. Dead stock was buried on 7 farms and composted on 2 farms.
Nutrition
The survey was conducted on 28 case herds and 33 control herds. There was nutrition information available from 25 case and 28 control herds. The diets fed to the nursery pigs were similar in case and control farms (Tables 5-7). The most significant differences were the length of time the pigs were fed each diet. Control herds kept nursery pigs on high-level, earlier feeds longer than case herds. The first diet was fed for 13.8 days in control herds but only 10.9 days in case herds (P=0.03) this resulted in 25 day old pigs in control herds and 22 day old pigs in case herds (P=0.04). The second diet was fed until pigs were 39 days o f age in control herds but until 33 days in case herds (P=0.07).
More control herds used spray dried plasma in the first nursery feed (97%) (P=0.001) and the second nursery feed (34%) (P=0.07) than case herds (61%; 13%).
The energy level was higher in the third nursery diet fed on case herds (3364) than on control herds (P=0.08).
In-feed antibiotics
Control herds were more likely to include lincomycin, and less likely to include chlortetracycline or penicillin in the creep diet than case herds. Control herds were more likely to use spectinomycin and less likely to use chlortetracycline in the third nursery diet.
Conclusions
Although these are still preliminary results from simple associations, there are indeed some interesting observations. The case herds do have a higher nursery pig mortality than the control herds and have a higher proportion of poor doing pigs at the end of the nursery phase.
The most obvious differences between the case and the control herds was the prevalence of clinical problems and disease agents. The case herds tended to be longer established herds situated closer to other pig farms and with more pigs farms within a 2 mile radius than the control herds. These all could lead to an increased likelihood of acquiring a disease agent.
Clinically, case herds have mover pale pigs, diarrhea and respiratory problems due to PRRS, and more coughing. Case herds are more likely to be positive for or observe clinical signs due to enterotoxigenic Ecoli, M hyopneumonia, TGE, K88 Ecoli causing nursery pigs losses, salmonella sp, swine influenza, rotavirus, circovirus, and Staph hyicus.
Case herds are more likely to vaccinate sows against PRRS and nursery pigs against M hyopneumonia and vaccinate younger pigs against M hyopneumonia than control herds.
It is interesting to note that most of the case herds (71%) and many of the control herds (46%) had a diagnosis of circovirus from the MLVS laboratory submissions. This may be due to the fact that case herds have a higher prevalence of the virus or that case herds submitted more samples to the diagnostic laboratory than control herds. Indeed, 5 case herds had more than 6 laboratory submission in the previous 12 month time period whereas only 1 control herds had this number of submissions (P<0.05). As mentioned above, of the three pigs submitted for post mortem as part of this study, 11 of 27 case herds had circovirus positive pigs, whereas only 2 of 30 control herds had circovirus positive pigs. It appears both in this province and in Ontario (Cottrell, 1999) that circovirus is widespread and can be found in herds that are not experiencing clinical signs due to PMWS.
Only two of the 28 case herds and none of the 33 control herds had experienced PMWS. The diagnoses for these two case herds was made by the producers due to clinical signs observed. However, during this study, one herd experiencing clinical problems in then nursery was identified as a PMWS positive herd with a positive circovirus identification.
There were several management factors identified by this survey that could lead to increased nursery pig problems in case herds when compared to control herds. These include fostering older pigs in the nursing phase of life, accepting a lower minimum weight and a higher maximum age for pigs to move into the nursery, sourcing nursery pigs from more than two sows herds and filling nursery pens with all pigs from the farrowing room or multiple farrowing rooms rather than keeping litters together. Similarly, case herds took longer to fill and to empty nursery barns which means that there is more mixing of pigs and a wider age range of pigs and more weeks of production within the barn. Case herds also did not have a much down time between fills as control herds. Case herds also provided fewer square feet per pig and accepted a higher maximum number of pigs per pen. As could be expected, pigs from case herds tended to be lighter when leaving the nursery.
Table 1: Number of pigs weaned per week, time spent in the nursery and
adjusted 7 week mortality rate.
|
Case Herds |
Control Herds |
Significance |
||||
|
Number of Farms |
28 |
33 |
Not significant |
|||
|
|
|
Avg |
SD |
Avg |
SD |
|
|
Pigs weaned |
Average |
359 |
274 |
409 |
577 |
NS |
|
Largest 25% |
510 |
X |
360 |
X |
|
|
|
Smallest 25% |
170 |
X |
150 |
X |
|
|
|
Time in the nursery barn |
Average |
6.8 |
1.5 |
7.3 |
2.4 |
NS |
|
Percent of pigs that are "light" at weaning |
Average |
10.1 |
9.1 |
7.9 |
8.0 |
|
|
Largest 25% |
10 |
X |
11.3 |
X |
|
|
|
Smallest 25% |
4 |
X |
2 |
X |
|
|
|
% of pigs that are poor doers at weaning |
Average |
3.7* |
5.0 |
1.6* |
1.7 |
P=0.01 |
|
Largest 25% |
4 |
X |
2 |
X |
|
|
|
Smallest 25% |
1.5 |
X |
0.5 |
X |
|
|
|
Number of Farms |
24 |
24 |
|
|||
|
7 - week mortality rate |
Average |
4.6 |
|
1.6 |
|
P=0.00003 |
|
Largest 25% |
6.3 |
X |
2.3 |
X |
|
|
|
Smallest 25% |
1.8 |
X |
0.8 |
X |
|
|
* indicates within row differences of P<0.05 |
||||||
Table 2: Clinical signs observed in nursery pigs during farm visit in post weaning mortality in Manitoba swine study, 1999
|
|
|
Case Herds | Control Herds | Significance |
|
Number of farms |
13 |
9 |
|
|
|
Prevalence of clinical signs |
Coughing |
0.4% |
0% |
NS |
|
Puffing |
23% |
18% |
NS |
|
|
Pale |
8%** |
4%** |
P=0.06 |
|
|
Jaundiced |
0% |
0.2% |
NS |
|
|
Scouring |
5% |
0.1% |
NS |
|
|
Wasting |
5% |
3% |
NS |
|
** indicates within row differences of P<0.10 (listed in text as "tended to differ") |
||||
Table 3: Proportion of herds positive for specific infectious disease agents and in which clinical signs occur in nursery pigs (either in the past or currently) for 61 farms that participated in the post weaning mortality in Manitoba swine study, 1999
| Disease |
Case (28 herds) |
Control (33 herds) |
||||
| Positive |
Clinical Signs |
Positive |
Clinical Signs |
|||
| Past | Current | Past | Current | |||
| A pleuropneumonia |
8 |
0 |
4.2 |
6 |
3.2 |
0 |
| A suis |
13 |
4.4 |
0 |
13 |
6.6 |
3.3 |
| Atrophic rhinitis |
20* |
4.0 |
0 |
6 |
3.0 |
0 |
| Circovirus |
71* |
0 |
0 |
46 |
0 |
0 |
| Ecoli diarrhea |
100** |
32 |
18 |
79 |
18.5 |
18 |
| Ecoli K88:sudden death |
50* |
27 |
35* |
22 |
12.5 |
12.5 |
| Ecoli: edema disease |
4.3 |
0 |
0 |
10 |
0 |
0 |
| M hyopneumonia |
61* |
21** |
14 |
25 |
6.3 |
6.3 |
| Staph hyicus (greasy pig) |
82 |
49 |
29 |
76 |
21 |
9.1 |
| H parasuis (glassers) |
64 |
36* |
25* |
78 |
28 |
18.8 |
| PRRS |
68 |
50 |
50 |
42 |
18 |
18 |
| Salmonella |
36 |
18* |
11 |
19 |
3.2 |
3.2 |
| Strep suis |
100 |
61 |
36 |
82 |
46 |
21.2 |
| Swine dysentry |
7 |
0 |
0 |
0 |
0 |
0 |
| Swine influenza |
11 |
3.6 |
11* |
21 |
9.1 |
0 |
| Rotavirus diarrhea |
44 |
27* |
11 |
32 |
6.5 |
6.5 |
| TGE |
11* |
7.4 |
0 |
13 |
9.4 |
0 |
* proportions differ at P < 0.05 ** indicates within row (column type) differences of P<0.10 (listed in text as "tended to differ") |
||||||
Table 4: Use of veterinary and diagnostic laboratory assistance in the past 12 months
|
Case n = 28 |
Control n = 33 |
||||
|
AVG |
SD |
AVG |
SD |
||
| Veterinary herd visits in last 12 months | No herd visits in last 12 months |
3.6 |
1 |
6.1 |
2 |
| Visits per 1000 weaned pigs per month |
.427 |
.424 |
.420 |
.380 |
|
|
% |
n + |
% |
n+ |
||
| 1-2 visits |
32.1 |
9 |
39.4 |
13 |
|
| 3-6 visits |
35.7 |
10 |
30.3 |
10 |
|
| > 6 visits |
28.6 |
8 |
24.2 |
8 |
|
|
AVG |
SD |
AVG |
SD |
||
| Submissions to Veterinary Laboratory Services | No submissions in last 12 months |
7.1* |
2 |
6.1* |
2 |
| Submissions per weaned pig per month |
.32 |
.38 |
.34 |
.31 |
|
|
% |
n + |
% |
n + |
||
| 1-2 submissions |
42.9 |
12 |
48.5 |
16 |
|
| 3-6 submissions |
32.1 |
9 |
42.4 |
14 |
|
| > 6 submissions |
17.9 |
5 |
3.0 |
1 |
|
Table 5: Creep feed / first nursery feed used for nursery pigs
| Case | Control | P | ||||
| AVG | SD | AVG | SD | |||
| Age when start the feed | 11.6 | 4.0 | 10.9 | 3.3 | ||
| Age when finish the feed | 22.4 | 3.2 | 24.7 | 5.3 | 0.04 | |
| Days fed this feed | 10.9 | 4.4 | 13.8 | 6.1 | 0.03 | |
| Protein | 20.6 | 4.13 | 21.4 | 0.79 | ||
| Lysine | 1.51 | 0.33 | 1.59 | 0.11 | ||
| Energy | 3353 | 677 | 3477 | 103 | ||
| % | n | % | n | |||
| Complete feed | 93 | 26 | 97 | 32 | -- | |
| Mixed on farm | 3.5 | 1 | 3 | 1 | -- | |
| Pelleted | 86 | 24 | 94 | 31 | -- | |
| Spray dried plasma | 61 | 14 | 97 | 32 | 0.001 | |
| Medications | Carbadox | 7 | 2 | 4 | 1 | -- |
| Chlortetracycline | 50 | 14 | 4 | 1 | 0.002 | |
| Lincomycin | 36 | 10 | 79 | 22 | 0.002 | |
| Penicillin | 39 | 11 | 29 | 8 | 0.0001 | |
| Spectinomycin | 32 | 9 | 54 | 15 | 0.17 | |
| Sulphamethazine | 36 | 10 | 25 | 7 | -- | |
| Tiamulin | 18 | 5 | 11 | 3 | – | |
| Combination | 82 | 23 | 54 | 15 | ||
Table 6: Second nursery feed used for pigs
| Case | Control | P | ||||
| AVG | SD | AVG | SD | |||
| Age when start the feed | 22.4 | 3.2 | 24.7 | 5.3 | 0.04 | |
| Age when finish the feed | 33.1 | 11.8 | 39.6 | 14.2 | 0.07 | |
| Days fed this feed | 10.9 | 10.3 | 15.4 | 11.4 | 0.13 | |
| Protein | 19.3 | 4.0 | 20.2 | 0.8 | ||
| Lysine | 1.39 | 0.33 | 1.41 | 0.19 | ||
| Energy | 3267 | 689 | 3378 | 131 | ||
| % | n | % | n | |||
| Complete feed | 68 | 19 | 58 | 19 | -- | |
| Mixed on farm | 29 | 8 | 42 | 14 | -- | |
| Pelleted | 64 | 18 | 58 | 19 | -- | |
| Spray dried plasma | 13 | 3 | 34 | 11 | 0.07 | |
| Medications | Carbadox | 7 | 2 | 13 | 4 | |
| Chlortetracycline | 41 | 11 | 30 | 9 | ||
| Lincomycin | 26 | 7 | 43 | 13 | 0.13 | |
| Oxytetracycline | 4 | 1 | 0 | 0 | ||
| Penicillin | 41 | 11 | 20 | 6 | 0.14 | |
| Sulpha | 33 | 9 | 13 | 4 | ||
| Tiamulin | 4 | 1 | 13 | 4 | ||
| Combinations | 63 | 17 | 57 | 17 | ||
Table 7: Third nursery phase diet used
| Case | Control | |||||
| AVG | SD | AVG | SD | P | ||
| Age when start the feed | 29.0 | 4.9 | 38.8 | 12.7 | 0.001 | |
| Age when finish the feed | 48.4 | 14.1 | 58.9 | 21.1 | 0.14 | |
| Days fed this feed | 21.4 | 13.9 | 20.0 | 12.7 | -- | |
| Protein | 19.1 | 1.1 | 19.4 | 0.8 | ||
| Lysine | 1.31 | 0.12 | 1.27 | 0.14 | ||
| Energy | 3364 | 92 | 3304 | 12 | 0.08 | |
| % | n | % | n | |||
| Complete feed | 48 | 11 | 52 | 16 | ||
| Mixed on farm | 52 | 12 | 48 | 15 | ||
| Pelleted | 48 | 11 | 48 | 15 | ||
| Spray dried plasma | 0 | 0 | 3 | 1 | ||
| Medications | Carbadox | 28 | 5 | 23 | 6 | -- |
| Chlortetracycline | 61 | 11 | 27 | 7 | 0.03 | |
| Lincomycin | 11 | 2 | 31 | 8 | -- | |
| Oxytetracycline | 0 | 0 | 7 | 2 | -- | |
| Penicillin | 39 | 7 | 23 | 6 | -- | |
| Spectinomycin | 0 | 0 | 23 | 6 | 0.06 | |
| Sulpha | 33 | 6 | 15 | 4 | -- | |
| Tiamulin | 6 | 1 | 4 | 1 | – | |
| Combinations | 50 | 9 | 50 | 13 | ||
