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Sirvi Autor "Sematovica, I." järgi

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  • Pisipilt
    Kirje
    Control of subacute ruminal acidosis in high-yielding dairy cow herd by measuring the rumen wall thickness
    (Estonian University of Life Sciences, 2024) Sematovica, I.; Malniece, A.; Duritis, I.
    The study aimed to investigate whether the rumen wall thickness (RWT) follows with the data from the collar sensor system and how deeply it depends on feeding management used in the high-yielding dairy cow farm, as well as what benefit it could bring to diagnose subacute rumen acidosis (SARA) in cows. The data obtained from the collar sensors about chewing activity were analysed in relation to milk recording results, the rumen wall thickness (RWT) and the context of the composition of feed easily digestible carbohydrate changes during the intensive lactation phase. The dynamic of RWT was evaluated concerning milk amount and quality, its relation to fertility, and the size of the cows, which were taken into account. The results showed that the sensor system provides information about cow behaviour but does not provide direct information about the SARA problem in the herd. The RWT was related to the changes in feed easily digestible carbohydrate content and chewing activity. In conclusion, the sensor system allows monitoring of feed ingestion, but overall data about productivity and milk composition are necessary to make conclusions and induce ideas about corrections. Additional RWT measures are necessary to monitor rumen health and SARA presence timely, so monitoring the RWT may lead to a longer productive life for the cow.
  • Pisipilt
    Kirje
    The cow reproductive perspective in relation to the colostrum quality and udder health in early lactation
    (Estonian University of Life Sciences, 2025) Lusis, I.; Sematovica, I.; Ostrovska, M.
    The study aimed to evaluate cow reproductive performance in relation to colostrum quality measured using a digital Brix refractometer and udder health in early lactation. A dataset of 676 cows was collected from one commercial dairy farm in Latvia over 36 months in 2022–2024. Colostrum Brix% was associated with the year and season of the year. The colostrum quality, as measured by the Digital Brix refractometer, was acceptably high, ranging from 23 to 30 in all cows during the study. The main individual factors associated with colostrum Brix% were the number of lactations, the sex of the calf, and lactose content in the first milk recording after calving. No association was detected between colostrum Brix% and the length of the dry period or the last milk recording data. Neither somatic cell count nor colostrum Brix% was associated with reproductive performance, service period, or the number of inseminations.
  • Pisipilt
    Kirje
    Embryo transfer results in endangered cow breeds in Latvia
    (2020) Sematovica, I.; Ponomarjova, O.; Kanska, I.; Vanaga, A.; Martinsons, T.
    Since 2017 multiple ovulation (MO) and embryo transfer (ET) were used to save endangered cow breeds in Latvia. The aim of this work was to analyse results to establish factors influenced recipients’ pregnancy obtained up to now. Recipients age, induced (IRC) or native reproductive cycle (NRC), level of estradiol (E2) and progesterone (P4) in recipients’ blood on ET day, stage and quality of embryo, fresh or thawed embryo usage and person provided ET were taken into account. Repeated artificial insemination (AI) had been provided in 19 (22.1%) recipients before ET. Pregnancy was accepted in 23 out of 76 recipients (30.3%) until now. Higher pregnancy results were obtained using fresh embryos (19 out of 53 (35.8%)) vs thawed embryos (4 out of 23 (17.4%)), (P < 0.05). The IRC was more productive than NRC (P < 0.05). The development stage, quality of embryos, E2 level were significant factors to reach pregnancy (P < 0.05) but recipients age, P4 level and person provided ET did not influence the pregnancy rate in the present study (P > 0.05). More successful pregnancies were reached using embryos obtained from donors which had a higher glucose and cholesterol level in blood (P = 0.05). In conclusion, our newly educated MOET team should gain their experience and results could be improved using IRC in recipients, fresh embryos, and more attention could be paid to the donorcows management in order to reach more qualitative embryos. Somatic cell count in the donors’ milk could be one of the indicator to avoid unsuccessful embryo obtaining.