Abstract
The present study was conducted to evaluate rheological properties of the vaginal fluid in dairy cows. Thixotropy and flow behavior were evaluated. Vaginal fluid samples were collected in 8 cows at the beginning of a natural estrus and then every 8 h for 24 h. Vaginal samples were also collected from 208 cows at the time of insemination within 12 to 24 h interval after the onset of a natural estrus. Time-dependent variations were registered during the estrus. The limit shear stress for flow production (T(o)), the shear stress of equilibrium (T(e)) and the consistency index (K) decreased at 8 and 16 h and markedly increased 24 h after the beginning of estrus. At the time of insemination, structural variation was registered and the fluids were considered to be thixotropic in samples of 181 cows (87%); in the remaining samples (27 cows), structural variation was not registered and the fluids were considered to be nonthixotropic. For flow behavior values, 178 samples (85.6%) presented non-Newtonian behavior, while 30 behaved as Newtonian fluids. The mean values of the T(o) and the T(e) were 6.1 ± 0.69 and 19 ± 06.9 pascals, respectively. Consistency index (K) mean was 364.9 ± 41.4 milipascals per second(n). Our data show an increase of fluidity at the middle of the estrus period in the cow and a wide variation of theological measurements of vaginal fluid at the time of insemination.
Original language | English |
---|---|
Pages (from-to) | 57-63 |
Journal | Theriogenology |
Volume | 46 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Jan 1996 |
Keywords
- dairy cows
- flow behavior
- thixotropy
- vaginal fluid