@article{KawashimaKidaSchweigertetal.2009,
  author    = {Kawashima, Chiho and Kida, Katsuya and Schweigert, Florian J. and Miyamoto, Akio},
  title     = {Relationship between plasma beta-carotene concentrations during the peripartum period and ovulation in the first follicular wave postpartum in dairy cows},
  issn      = {0378-4320},
  doi       = {10.1016/j.anireprosci.2008.02.008},
  year      = {2009},
  abstract  = {beta-Carotene functions independently of vitamin A in the reproductive performance of dairy cows. The concentrations of beta-carotene in plasma decrease during the dry period, and reach a nadir in about the first week postpartum. This coincides with a negative energy balance, which affects the onset of the first ovulation in early postpartum cows. Thus, we hypothesised that plasma beta-carotene concentrations during the peripartum period may affect ovulation in the first follicular wave postpartum in dairy cows. The aim of the present study was to investigate changes in the profiles of plasma beta-carotene concentrations during the peripartum period in ovulatory and anovulatory cows during the first follicular wave postpartum. We used 22 multiparous Holstein cows, which were fed a total mixed ration consisting of grass, corn silage and concentrate, and collected blood samples for beta-carotene and progesterone analysis from week 3 prepartum to week 3 postpartum when the period of day 0-6 after parturition was regarded as the parturient week (week 0). The first ovulation was confirmed using the profile of plasma progesterone concentrations and colour Doppler ultrasound. Thirteen cows ovulated during the first postpartum follicular wave. Parity, the dry-off period, calving interval, mastitis episodes, and actual 305 days' milk yield during the previous lactation, and milk composition in the last month during the previous lactation in this study did not differ between ovulatory and anovulatory cows. Differences in the plasma beta-carotene profile were observed between ovulatory and anovulatory cows. Plasma P-carotene concentrations at week 3 prepartum were greater in ovulatory cows (2.97 +/- 0.24mg/L) than in anovulatory cows (1.53 +/- 0.14mg/L; P < 0.001), after that its concentrations in ovulatory cows decreased and reached the lowest level at week I postpartum, although its concentrations in anovulatory cows remained unchanged. No differences in plasma P-carotene concentrations between the two groups were observed postpartum. The present study indicates for the first time that the lower P-carotene concentrations in plasma during the prepartum period is associated with anovulation during the first follicular wave postpartum.},
  language  = {en}
}
@article{KawashimaItoNagashimaetal.2016,
  author    = {Kawashima, Chiho and Ito, Nozomi and Nagashima, Shuntarou and Matsui, Motozumi and Sawada, Kumiko and Schweigert, Florian J. and Miyamoto, Akio and Kida, Katsuya},
  title     = {Influence of hepatic load from far-off dry period to early postpartum period on the first postpartum ovulation and accompanying subsequent fertility in dairy cows},
  series = {The journal of reproduction and development : official journal of the Japanese Society of Animal Reproduction},
  volume    = {62},
  journal   = {The journal of reproduction and development : official journal of the Japanese Society of Animal Reproduction},
  publisher = {Utha State University},
  address   = {Tsukuba},
  issn      = {0916-8818},
  pages     = {289 -- 295},
  year      = {2016},
  abstract  = {The aim of the present study was to investigate nutritional and metabolic parameters during the dry and early postpartum periods of ovulatory and anovulatory cows, as well as their postpartum reproductive performance. Blood samples from 20 multiparous Holstein cows were collected once a week from the far-off dry period to 3 weeks postpartum. Early postpartum (0-3 weeks) ovulation was confirmed using plasma progesterone concentration profiles, and cows were considered ovulatory if they had resumed luteal activity by this point (n = 9), whereas cows that had not were considered anovulatory (n = 11). Data from the ovulatory and anovulatory cows were analyzed separately for the far-off dry period (7-4 weeks prepartum), the close-up dry period (3-1 weeks prepartum), and the early postpartum period (0-3 weeks). Serum gamma-glutamyl transpeptidase activity (far-off, P = 0.065; close-up, P = 0.051; and early postpartum, P = 0.030) and aspartate aminotransferase (close-up, P = 0.050 and early postpartum, P = 0.087) activities were higher in anovulatory than in ovulatory cows. The days open period was longer (P = 0.019) in anovulatory than in ovulatory cows, and the number of artificial inseminations per conception (P = 0.025) was greater. In conclusion, we found that continuously high gamma-glutamyl transpeptidase activities in serum, which may be induced by liver disorders, prevent subsequent ovulation and affect subsequent fertility, even if cows obtain sufficient ovulation-related energy and beta-carotene.},
  language  = {en}
}