Dipsticks offer early warning of sow urinary-tract infections
Minimizing urinary-tract infections is an important step — not only in securing a sow’s overall health but also its productivity and, ultimately, its longevity.
Yet, the issue too often goes unnoticed and, like most cases in swine health, early intervention leads to a higher likelihood of success.
Applying a quick, easy and inexpensive a dipstick test is the first step, but ensuring its accuracy is essential.
Jewell Bremer, veterinary student at North Carolina State University, recently evaluated the accuracy of the urinary dipstick tests, as well as how urinary tract health impacts sow reproductive performance and mortality.1
“Previous research tells us that urinary tract infections associated with post-parturient swine urogenital disease decrease the farrowing rate and increase abortion and sow mortality2,” Bremer noted.
Comparing two tests
The study involved 292 late-term sows from four commercial farms within the same production company. Urine samples were collected via free-catch and/or the tampon method.3 A total of 141 urine samples were tested to compare laboratory pathology results to dipstick-test results.
Urinalysis included: glucose, blood, ketones, protein, nitrites, leukocytes, bilirubin, urobilinogen, specific gravity and pH. Abnormalities involved pH beyond the 5.5 to 7.0 range and specific gravity below 1.010.
Figure 1. Urinary profile examples quantifying positive reactions on dipstick urinalysis
Table 1. Summary of on farm urine dipstick versus in-lab urinalysis results confirming consistency
|Glucose||98.58%||0.970||No significant difference|
|Ketones||94.33%||0.074||No significant difference|
|Protein||53.90%||0.103||No significant difference|
|Specific gravity||85.82%||0.607||No significant difference|
Finding the two testing options were statistically comparable, urine samples from an additional 151 sows were tested using only the dipstick method.
A sow left the study once it was successfully weaned, returned to estrus and re-bred. Any sow that failed to complete any of those steps was characterized as having an “abnormal event,” Bremer told Pig Health Today.
“The dipstick test is a reliable tool that can be used on-farm to assess sow renal function and hydration status quickly and accurately,” Bremer said. “It can identify sows that may be suffering and allow treatment intervention, before the infection worsens and prognosis becomes poor.”
Specifically, the dipstick test can signal if a sow is dehydrated or if there is protein in its urine, providing insight into renal function. “We know that when the kidneys are working well, we will not find protein in the urine,” she added.
More specifically, finding protein in the urine prior to farrowing signals at-risk sows based on the following outcomes:
- 65% died or were euthanized.
- 60% had increased stillborn or mummified piglets.
- 25% were not re-bred after weaning.
Also, 25% of the sows that died were hyposthenuric, which means they had low specific-gravity urine — a signal that the animals’ kidneys may have been unable to concentrate the urine normally.
Not only is the dipstick an easy and more immediate urine test, it’s also significantly more cost-effective than a laboratory test. Bremer noted the following:
- A traditional lab-based urinalysis costs ~$15.50 per sow and takes 2-3 days for results.
- A urine dipstick test costs 13 cents per sow and takes 2 minutes for results.
“These dipsticks give the power back to the farmer and places the focus on individual sow health,” Bremer said. “I would like to see dipstick tests used for sows that appear not to be doing well as another step in determining what’s going on.”
For example, she pointed to clinical signs that can help identify a sow with a urinary-tract infection, such as foul-smelling urine, red-brown-colored urine, the animal being unwilling to stand or going off feed.
Bremer said more research is needed to better understand the impact that renal and hydration status have on sow productivity as well as the root causes of abnormal urinalysis and to identify possible interventions.
1Bremer J, et al. Validation of a urine dipstick as a tool to assess the potential impact of urinary tract health on reproductive performance and sow mortality. Student Research Poster, 49th Am Assoc Swine Vet Annual Meeting. 2018.
2Glock XTP, Bilkei G. The effect of postparturient urogential diseases on the lifetime reproductive performance of sows. Can Vet J 2005;46:1103–1107.
3Nickel M, et al. Development and validation of ante-mortem urine collection techniques for gilts and sows. Student Seminar,48thAm Assoc Swine Vet Annual Meeting. 2017;63.