A new technique for repeated biopsies of the mammary gland in dairy cows allotted to Latin-square design studies
Citation
de Lima, L. S., Martineau, E., De Marchi, F.E., Palin, M.F., dos Santos, G.T. and Petit, H.V. (2016) A new technique for repeated biopsies of the mammary gland in dairy cows allotted to Latin-square design studies. Canadian Journal of Veterinary Research 80(3): 225-229. PMCID: PMC4924557
Plain language summary
In nutritional studies with dairy cows, repeated biopsies are often needed. However, sampling of mammary tissue in dairy cows through biopsy has long been considered a difficult task due to its effects on milk production and mammary health. Indeed, when biopsies of the mammary gland are taken repeatedly, bleeding and mastitis may occur, whic may affect milk production in subsequent periods of the experiment and alter the response to treatments. The objective of this study was to develop a new biopsy technique that can be used frequently on lactating dairy cows and that provides enough material to perform different laboratory analyses from mammary tissue. The biopsy instrument consisted of 3 main pieces: a stainless steel trocar and cannula, and a 30-mL syringe used to create a vacuum. The trocar was inserted through the gland capsule with a gentle, manually driven circular motion and samples were withdrawn using the vacuum created by the syringe. This new biopsy technique helped to avoid excessive bleeding and accelerated healing of the mammary gland. This technique successfully allows tissue sampling of the mammary gland to be repeated every 3 weeks (up to 4 times) in lactating dairy cows. Although secondary complications are always a risk with any procedure, this biopsy technique was carried out without complications to the health of animals and there was no incidence of mastitis during the lactation.
Abstract
The objective of this study was to develop a technique for carrying out repeated biopsies of the mammary gland of lactating dairy cows that provides enough material to monitor enzyme activities and gene expression in mammary secretory tissue. A total of 16 Holstein cows were subjected to 4 mammary biopsies each at 3-week intervals for a total of 64 biopsies. A 0.75-cm incision was made through the skin and subcutaneous tissue of the mammary gland and a trocar and cannula were inserted using a circular motion. The trocar was withdrawn and a syringe was plugged into the base of the cannula to create a vacuum for sampling mammary tissue. To reduce bleeding, hand pressure was put on the surgery site after biopsy and skin closure and ice was applied for at least 2 h after the biopsy using a cow bra. The entire procedure took an average of 25 min. Two attempts were usually enough to obtain 800 mg of tissue. Visual examination of milk samples 10 d after the biopsy indicated no trace of blood, except in samples from 2 cows. All wounds healed without infection and subcutaneous hematomas resorbed within 7 d. There was no incidence of mastitis throughout the lactation. This technique provides a new tool for biopsy of the mammary gland condary complications leading to illness or death are always a risk with any procedure, this biopsyrepeated at short intervals with the main effect being a decrease in milk production. Although se technique was carried out without complications to the health of animals and with no incidence of mastitis during the lactation.