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. Mammary gland biopsies were performed using a disposable biopsy punch. The technique was also performed on multiparous cows on other independent research trials. RESULTS: One-hundred and thirteen animals healed from the 10-week biopsies with no complications. Of the 36 animals that received repeated biopsies, one developed mastitis due to premature suture removal and one had recurring mastitis in all quarters. Thirty-three animals underwent all biopsies during gestation. Thirty of the original 36 are currently in lactation and still undergoing repeated biopsies. The method has also been successfully replicated on multiparous cows in separate studies. DISCUSSION AND CONCLUSION: The described technique is a safe, reliable method for cattle mammary gland biopsies beginning at eight weeks of age and can be utilized to obtain repeated tissue collection from individual animals. The technique is also straightforward to perform and utilizes simple tools while providing acceptable amounts of tissue for most applications, with low risk for infection and long-term tissue damage.

The antidepressant fluoxetine (Prozac®) modulates serotonin signaling to alter maternal peripartum calcium homeostasis.

Antidepressant use is two-fold greater in women compared to men; however, most studies have been performed in male subjects. We aimed to understand the impact of selective serotonin reuptake inhibitors (SSRI, most used antidepressants) on calcium homeostasis and steroid metabolism during the peripartum period. Pregnant sheep (n = 10/group) were treated with vehicle or fluoxetine (most common SSRI) during the last month of gestation. Fluoxetine treatment decreased circulating calcium prior to parturition (8.7 ± 0.1 mg/dL vs 8.2 ± 0.1 mg/dL; P = 0.07). In the control group, total calcium decreased after parturition corresponding to the onset of lactogenesis followed by increase in calcium by day 2 postpartum. Interestingly, this normal transient decrease in circulating calcium was absent in fluoxetine-treated ewes. The steroids cortisol and progesterone were not altered by fluoxetine treatment whereas estradiol was decreased after the onset of treatment (12.4 ± 1.3 vs 9.1 ± 1.2 pg/mL, P = 0.05) and prior to parturition (38.1 ± 8.1 vs 22.3 ± 4.2 pg/mL, P = 0.03). Our hypothesis was supported that fluoxetine treatment alters circulating concentrations of calcium in the peripartum period; however, we surprisingly observed a decrease in estradiol concentrations contrary to reports in in vitro studies.

Longitudinal analysis of bovine mammary gland development.

Many studies on bovine mammary glands focus on one stage of development. Often missing in those studies are repeated measures of development from the same animals. As milk production is directly affected by amount of parenchymal tissue within the udder, understanding mammary gland growth along with visualization of its structures during development is essential. Therefore, analysis of ultrasound and histology data from the same animals would result in better understanding of mammary development over time. Thus, this research aimed to describe mammary gland development using non-invasive and invasive tools to delineate growth rate of glandular tissue responsible for potential future milk production. Mammary gland ultrasound images, biopsy samples, and blood samples were collected from 36 heifer dairy calves beginning at 10 weeks of age, and evaluated at 26, 39, and 52 weeks. Parenchyma was quantified at 10 weeks of age using ultrasound imaging and histological evaluation, and average echogenicity was utilized to quantify parenchyma at later stages of development. A significant negative correlation was detected between average echogenicity of parenchyma at 10 weeks and total adipose as a percent of histological whole tissue at 52 weeks. Additionally, a negative correlation between average daily gain at 10 and 26 weeks and maximum echogenicity at 52 weeks was present. These results suggest average daily gain and mammary gland development prior to 39 weeks of age is associated with development of the mammary gland after 39 weeks. These findings could be predictors of future milk production, however this must be further explored.