Risk factors for equine trypanosomosis and hematological analysis of horses in Paraguay.

Animal trypanosomosis, caused by Trypanozoon trypanosomes (Trypanosoma evansi and T. equiperdum), and Trypanosoma vivax, is endemic to South American countries and has a negative impact on the livestock industry. However, the risk factors for trypanosomosis in Paraguay remain unknown. This study aimed to determine the risk factors for equine trypanosomosis in Paraguay based on a PCR-based molecular survey and individual horse sampling data. In this study, 739 blood samples were collected from horses in 16 departments of Paraguay between August 2019 and November 2020. To elucidate the risk factors for trypanosome infection, the relationship between trypanosome infection status detected by PCR and the location, sex, age, breed of horses, and season of sample collection was analyzed. There were no significant differences in trypanosome prevalence in horses between the eastern and western regions, ages, or breeds of horses in Paraguay. Sex and season were identified as risk factors for trypanosome infection in horses in Paraguay in the current study. These results suggest that the rainy-summer season, when vectors increase in number and their blood-sucking activity, could be the most important risk factor for trypanosome infection in Paraguay horses. Preventive measures and treatments should be developed to address these factors.

Evaluation of Wearable Cameras for Monitoring and Analyzing Calf Behavior: A Preliminary Study.

Understanding cattle behavior is important for discerning their health and management status. However, manual observations of cattle are time-consuming and labor-intensive. Moreover, during manual observations, the presence or position of a human observer may alter the normal behavior of the cattle. Wearable cameras are small and lightweight; therefore, they do not disturb cattle behavior when attached to their bodies. Thus, this study aimed to evaluate the suitability of wearable cameras for monitoring and analyzing cattle behavior. From December 18 to 27, 2017, this study used four 2-month-old, group-housed Holstein calves at the Field Science Center of the Obihiro University of Agriculture and Veterinary Medicine, Japan. Calf behavior was recorded every 30 s using a wearable camera (HX-A1H, Panasonic, Japan) from 10:00 to 15:30 and observed directly from 11:00 to 12:00 and 14:00 to 15:00. In addition, the same observer viewed the camera recordings corresponding to the direct observation periods, and the results were compared. The correlation coefficients of all behavioral data from direct and wearable camera video observations were significant (p < 0.01). We conclude that wearable cameras are suitable for observing calf behavior, particularly their posture (standing or lying), as well as their ruminating and feeding behaviors.

Successful embryo transfer from Hokkaido native pony after artificial insemination with frozen semen.

There has been no report of equine embryo transfer in Japan for the last 24 years. Our objective was to establish an effective protocol for embryo transfer in domestic horse. A Hokkaido native pony was bred by deep-horn artificial insemination with frozen semen from a Connemara pony. Embryo collection was performed using a non-surgical method on day 7. Two embryos were obtained from three flushes (67% recovery) and were transferred fresh into crossbred recipient mares. Both recipient mares were diagnosed pregnant (100% pregnancy rate) 5 days after embryo transfer and had normal progesterone levels until the end of the observation on day 35 of gestation. This is the first successful embryo transfer in Japan by artificial insemination using frozen semen. Embryo transfer technology could be extremely useful in improving the productivity of Japanese domestic and special riding horses.