Comparing the efficacy of serotonin and EGTA on postpartum hypocalcemia.

Inducing a transient state of hypocalcemia prepartum mobilizes stored calcium (Ca) before the abrupt demand for Ca at parturition thus more tightly regulating postpartum hypocalcemia. Prepartum transient hypocalcemia can be achieved through intravenous infusions of either the precursor to serotonin, 5-hydroxy-tryptophan (5HTP) or a Ca chelating agent, ethylene-glycol-tetraacetic acid (EGTA). This study aimed to compare the ability of 5HTP and EGTA treatments to prevent postpartum hypocalcemia.

Effects of induced subclinical hypocalcemia in early-lactation Holstein cows without milking during infusion on parathyroid hormone and serotonin concentrations.

The transition to lactation demands a substantial amount of calcium (Ca) to support colostrum and milk production. Extensive research has been focused on elucidating the interplay between the traditional Ca-parathyroid hormone-vitamin D axis and mammary-derived factors, such as serotonin (5-HT) and parathyroid-hormone-like hormone (PTHLH), in regulating Ca metabolism during the transition period. Here, we investigate the impact of induced subclinical hypocalcemia (SCH) on 5-HT and parathyroid hormone (PTH) concentrations in early-lactation dairy cows under conditions of 24-h milk stasis.

Monitoring mammary gland development in preweaning dairy heifers using ultrasound imaging.

Existing literature on the long-term effects of nutritional manipulation on milk production is incomplete and inconsistent as animals are typically culled before lactation. In addition, longitudinal studies are rarely conducted due to high costs and constraints related to tissue sampling; therefore, additional research is necessary to better understand the effect of early nutrition and growth on subsequent growth and milk production. Thirty Holstein heifer calves were pair-fed high (H; 27% CP and 20% fat) or low (L; 22% CP and 15%) milk replacers.

Ultrasound-assisted minimally invasive technique for tissue collection from bovine mammary glands.

Background And Aims: The objective of this case report was to describe an ultrasound-guided, minimally invasive method for longitudinal mammary gland tissue collection from the bovine species.

Materials And Methods: Biopsies were performed on 14 8-week-old calves and 113 10-week-old calves. A subset of 36 animals had repeated mammary gland biopsies through the first lactation.

Hormonal profiles and biomarkers leading to parturition in cattle†.

This study aimed to understand the physiological mechanisms regulating parturition and to identify potential biomarkers to predict onset of birth. Additionally, we compared hormone profiles between cows with shorter and longer gestation lengths. Twenty-eight days before due date until 3d postpartum, cows (n = 18) were blood-sampled daily.