title: Relationship of ruminal temperature with parturition and estrus of beef cows.
abstract: Spring-calving Angus cows (n = 30) were used to evaluate changes in ruminal temperature (RuT) related to parturition and estrus. Cows were synchronized and artificially inseminated with semen from a single sire. Temperature boluses were placed in the rumen at 7.0 ± 0.2 mo of gestation. Boluses were programmed to transmit RuT every 15 min. Cows (BW = 623 ± 44 kg, BCS = 4.9 ± 0.4) calved during 3 wk, and estrus was synchronized at 77 ± 7 d after calving with PGF(2α). Cows were observed every 12 h to detect estrus. Daily average ambient temperatures ranged from 2 to 22 °C during parturition (February to March) and 17 to 25 °C during estrus (May to June). Ruminal temperature from 7 d before to 3 d after parturition and 2 d before to 2 d after visual detection of estrus was analyzed using the MIXED procedure. Ruminal temperatures <37.72 °C were attributed to water consumption and excluded from analyses. Day did not influence (P = 0.36) RuT from d -2 to -7 before parturition (38.94 ± 0.05 °C). Ruminal temperature decreased (P < 0.001) from d -2 to d -1 before parturition (38.88 ± 0.05 to 38.55 ± 0.05 °C, respectively). Ruminal temperature was not influenced (P = 0.23) by day from 1 d before to 3 d after parturition (38.49 ± 0.05 °C). Ruminal temperature at 0 to 8 h after detection of estrus (38.98 ± 0.09 °C) was greater (P < 0.001) compared with RuT at the same daily hour of the day before (38.37 ± 0.11 °C) or the day after estrus (38.30 ± 0.09 °C). Ambient temperature did not influence (P > 0.30) RuT at parturition or estrus. Ruminal temperature decreased the day before parturition and increased at estrus in spring-calving beef cows and has potential use as a predictor of parturition and estrus.
authors.affiliation: Department of Animal Science, Oklahoma Agricultural Experiment Station, Oklahoma State University, Stillwater 74078-0425, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Cooper-Prado
authors.forename: N M
authors.initials: NM
authors.lastname: Long
authors.forename: E C
authors.initials: EC
authors.lastname: Wright
authors.forename: C L
authors.initials: CL
authors.lastname: Goad
authors.forename: R P
authors.initials: RP
authors.lastname: Wettemann
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D001831:Body Temperature; D002417:Cattle / Q000502:physiology*; D004971:Estrus; D005260:Female; D036801:Parturition; D058998:Remote Sensing Technology; D012417:Rumen / Q000502:physiology*