# Liver Biopsy Technique for Analysis of Hepatic Content during Pregnancy and Early Lactation in Dairy Goats

## TL;DR

This study introduces a safe liver biopsy method for dairy goats to analyze liver content during pregnancy and early lactation.

## Contribution

A new liver biopsy technique for dairy goats is described, enabling safe hepatic triglyceride and glycogen analysis.

## Key findings

- Liver biopsies did not affect dry matter intake, body weight, or milk yield in dairy goats.
- High milk production was associated with lower hepatic triglyceride levels.
- Glycogen levels decreased 15 days after calving compared to pre-calving levels.

## Abstract

Liver biopsy is a minimally invasive technique for liver evaluation, but its use is limited in dairy goats. Here, our main goal was to describe a liver biopsy method suitable for goat herds. The liver biopsy technique allows for the taking of liver samples to measure hepatic triglycerides and glycogen while preserving animal health and welfare. We evaluated the major factors that may cause changes in hepatic content in dairy goats, such as the peripartum period, number of fetuses, diet, supplementation, and milk production. The level of milk production and days relative to parturition influence hepatic triglyceride levels and glycogen content in dairy goats.

Biopsy techniques in dairy goats are currently limited. This study aimed to describe a liver biopsy technique in dairy goats and to evaluate liver triglyceride levels and glycogen content. Sixty-nine dairy goats in the final stage of pregnancy and early lactation period were selected. Fifty goats were selected randomly for hepatic biopsy (HB) according to gestational period and were characterized according to fetus number (single: n = 16, multiple: n = 34), supplementation with propylene glycol (diet: n = 23, diet+PG: n = 27), and milk production levels (high: 3.0 ± 0.4 L/day, n = 15; low: 1.4 ± 0.4 L/day, n = 26). Liver tissue samples were obtained through biopsy on days −30, −20, −15, −10, −5, and 15 days after calving. Hepatic triglyceride and glycogen were quantified. The results were analyzed using the F-test at a 5% significance level and a comparison of means using the Tukey test. The liver biopsies did not influence dry matter intake, body weight, or milk yield. Hepatic glycogen concentration was lower 15 days after calving than it was prior to calving, except on day −20. Goats that generated high levels of milk production had lower triglyceride levels than goats that generated low levels of milk production. The biopsy technique is a safe method for obtaining tissue and evaluating liver content in dairy goats. The milk production level and days relative to parturition influence the hepatic triglyceride and glycogen content in dairy goats.