The effects of rumen-protected choline and l-carnitine supplementation in the transition period on reproduction, production, and some metabolic diseases of dairy cattle

Abstract

This experiment was designed to examine the effects of l-carnitine and choline on production parameters, reproduction indices, as well as ketosis and fatty liver indicators in pre- and post-partum Holstein cows. A number of 120 dairy cows were randomly allocated to four treatment groups: protected choline (60 gm/day per cow), l-carnitine (50 gm/day per cow), choline + l-carnitine (60 + 50 gm/day per cow), and control group (without supplement). Treatments were given from one week before calving to four weeks after calving. Milk and blood samples were collected at the time of calving till four successive weeks. Results showed that combined choline and l-carnitine supplementation increased milk fat % (3.93 ± 0.11), but decreased solids-non-fat % (8.04 ± 0.10) and lactose % (3.92 ± 0.05). Reproduction indices – including service/conception rate (1.24 ± 0.40), calving to first visible oestrus (53.36 ± 8.20), calving to first service (59.07 ± 4.20 days), and days open (63.36 ± 8.10 days) – were improved for combined choline and l-carnitine group. A significantly lower level of aspartate aminotransferase (50.16 ± 5.96) and a higher level of beta hydroxy butyrate acid (0.31 ± 0.10) were observed in blood serum when combined choline and l-carnitine was supplemented. In conclusion, concomitant administration of choline and l-carnitine improved reproduction indices as well as the liver health index in Holstein cows.

Keywords

• Choline
• l-carnitine
• (re)production
• transition period
• dairy cattle