REPRODUCTIVE PERFORMANCE OF DAIRY COWS SUPPLEMENTED WITH A LOW DOSE OF OMEGA-3 FATTY ACIDS

In recent decades, supplementation of dairy cows with different sources of omega-3 fatty acids (FA) has increased with the aim of improving reproductive performance. These results have been reported by several authors (Royo et al. 2021, Gulliver et al. 2012, Santos et al. 2008; Ambrose et al 2006). However, due to the increasing costs of raw materials used in animal feed, we believe it is important to know if the beneficial effect on reproductive performance is maintained using a low dose (250 g HI-FLAX® per cow per day).

In order to evaluate the effect of TMR supplementation with omega-3 bypass FA (Norel HI-FLAX®) at low dose on reproductive parameters of a dairy herd, 91 adult Holstein cows were enrolled in the study for 8 weeks. The TMR for the cows was supplemented with 250 g/cow/day of HI-FLAX® (FAO3), which corresponds to 35 g of omega-3 FA. Cows consumed this TMR for at least 2 weeks prior to artificial insemination (AI). The cows that did not consume omega-3 FA prior to artificial insemination were considered as the CONTROL group (CTRL).

The pregnancy percentage of the farm was 30% at each insemination. However, when we analyzed the pregnancy percentage in each experimental group, we observed significant differences (P = 0.004) between them. CTRL cows, those that did not consume omega-3 fatty acids prior to insemination, had a pregnancy rate of 27%, while cows that were supplemented with omega-3 fatty acids (FAO3) prior to insemination obtained a pregnancy rate of 50%.

Regarding the total number of AI required to achieve a pregnancy, significant differences (P = 0.003) were also observed between the two groups. Cows that were not supplemented with omega-3 FA (CTRL) required an average of 3.2 AIs to achieve a pregnancy, while cows that consumed HI-FLAX® required only 1.5 AIs. Open days are defined as the time between the last calving and the fertilizing AI.  This time had a tendency (P = 0.1) to be different between the two groups. In the case of cows supplemented with omega-3 FA (FAO3) this time was on average 100 days, however, in the non-supplemented cows (CTRL) this time lasted on average 169 days.

With this trial it was concluded that supplementation with omega-3 fatty acids (HI-FLAX®) at a dose of 250 g/cow per day, significantly increased the pregnancy rate. This meant that these cows became pregnant earlier, requiring fewer inseminations, and having fewer days open than cows that did not receive these fatty acids.