Combined Effects of Human Chorionic Gonadotropin and Intravaginal Progesterone Device Treatment in the Early Luteal Phase After Artificial Insemination on Conception Rate in Lactating Dairy Cows
Ryotaro Miura,
Taiki Izumi,
Yuriko Wada,
Yujiro Hagita,
Kosuke Iga,
Natsumi Sobu,
Akiya Hirase,
Osamu Yoneyama,
Yo-ichi Miyake,
Tsuyoshi Tajima,
Tadaharu Ajito,
Shingo Haneda,
Motozumi Matsui
Affiliations
Ryotaro Miura
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Kyonan, Musashino 180-8602, Japan
Taiki Izumi
Tokachi NOSAI, Kawanishi, Obihiro 089-1182, Japan
Yuriko Wada
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Kyonan, Musashino 180-8602, Japan
Yujiro Hagita
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Kyonan, Musashino 180-8602, Japan
Kosuke Iga
Division of Advanced Feeding Technology Research, Institute of Livestock and Grassland Science, NARO, Tsukuba 305-0901, Japan
Natsumi Sobu
Tokachi NOSAI, Kawanishi, Obihiro 089-1182, Japan
Akiya Hirase
Tokachi NOSAI, Kawanishi, Obihiro 089-1182, Japan
Osamu Yoneyama
Toyonishi Livestock Clinic, Toyonishi, Obihiro 089-1183, Japan
Yo-ichi Miyake
Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro 080-8555, Japan
Tsuyoshi Tajima
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Kyonan, Musashino 180-8602, Japan
Tadaharu Ajito
Department of Veterinary Medicine, Nippon Veterinary and Life Science University, Kyonan, Musashino 180-8602, Japan
Shingo Haneda
Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro 080-8555, Japan
Motozumi Matsui
Department of Clinical Veterinary Science, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro 080-8555, Japan
The combined effects of human chorionic gonadotropin (hCG) treatment on Day 5 (Day 0 = the day of artificial insemination: AI) and intravaginal progesterone device (IVPD) treatment from Day 5 to 19 on the conception rate and plasma sex steroid hormone were examined in lactating dairy cows. In Experiment 1, cows were divided into a non-treatment group (n = 181), untreated; an IVPD group (n = 74), with an IVPD inserted into the vagina from Day 5 to 19; and an hCG + IVPD group (n = 87), with 3000 IU hCG administered intramuscularly on Day 5 and an IVPD inserted into the vagina from Day 5 to 19. The conception rates of the hCG + IVPD group, which underwent ≤3 AIs (52.8%) and >3 AIs (73.3%), and the IVPD group, which underwent >3 AIs (63.0%), were significantly higher than that of the non-treatment group, which underwent ≤3 AIs (34.2%). In Experiment 2, blood samples were collected from the non-treatment group (n = 6), the IVPD group (n = 6), and the hCG + IVPD group (n = 7) on days 5, 8, 12, and 15 from estrus to measure plasma progesterone (P4) and total estrogen (E) concentrations. The plasma P4 concentration of the hCG + IVPD group tended to be higher than that of the non-treatment group on Day 15; however, plasma E concentrations were not different among groups. These results suggest that the conception rate was improved by hCG + IVPD treatment regardless of AI number because of higher plasma P4 concentrations later in the estrous cycle.
