Impact of TMR preservation with Selko TMR on dairy milk production and feeding behavior during warm weather

This study aimed to assess the effects of Selko TMR on the performance, rumen fermentation, and feeding behavior of dairy cattle during the warm weather season. The research, conducted at Kempenshof Ruminant Research Centre, included the entire herd of 120 animals, blocked by days in milk and parity. Despite an unexpected lack of difference in dry matter intake, Selko TMR demonstrated a tendency to increase milk yield by 1.7 kg in week 5, leading to significantly higher yields of milk solids. Feeding behavior analysis revealed that Selko TMR-fed cows spend less time eating, demonstrating potential improvements in TMR palatability.

The study was carried out with 120 lactating dairy cows, of which eight were fistulated, at the Trouw Nutrition dairy research centre (Kempenshof, the Netherlands). Cows were blocked based on parity and days in milk. Both groups of 60 dairy cows were fed the same diet based on a mixture of grass and corn silage, mixed into a TMR, and the first week was considered an adaptation period. The treatment group received TMR including 2 kg/t of Selko-TMR (Treatment table). Both groups were fed once a day for a total study period of 7 weeks.

Average daily temperatures were between 20 and 30 °C (= 68-86 °F) during the study and maximum temperatures reached up to just above 35 °C (= 95 °F). The temperature heat index was regularly above 72, suggesting that the cows were suffering from heat stress. Dry matter intake (DMI) and the volatile fatty acids (VFA) profile of the rumen fluid did not differ significantly. The DMI of the TMR was significantly lower in the Selko-TMR group during the adaptation period (Figure 1; -1.3 kg/day; p=0.02).

At the start of the study, there was an insignificant difference of 0.3 kg/day (p=0.52) in milk production between the treatment groups. This difference tended to increase towards the end of the study with the cows fed the TMR with Selko-TMR producing 1.7 kg/day more milk compared to the control group (p = 0.07; Figure 2).

As a result, a similar trend was found for milk protein, fat, and lactose yield with significantly higher yields (kg per day) at different time points in the Selko-TMR group. Body condition scores showed no differences. Rumen VFA, rumen pH, and health parameters remained consistent between groups.

Selko TMR-fed cows exhibited faster eating, with fewer visits per day compared to the control group. The feeding pattern varied throughout the day, indicating a potential impact of Selko TMR on feeding behavior. Selko TMR fed cows visited and spend less time at the feeding station compared to the control group.

The intake rate (g wet/min) was significantly lower in the control group during the night, afternoon and evening (Figure 3; p <0.01). The visit durations were shorter in Selko TMR group during the whole day (p=0.04) but most profound at morning (p =0.004) and afternoon (p=0.0006); (Figure 4.)

The study suggests that Selko TMR, despite not influencing dry matter intake, may contribute to improved milk yield and composition, along with altered feeding behavior. The control group visited the feeding station more times per day and spend more time eating which indicates more feed selecting behaviour as most of the feeding behaviour measures demonstrate that cows with more visits per day, spend less time at each feeder visit with a lower intake per visit or meal (Cavani et al. 2022).

The observed rise in milk production and decreased signs of feed selection are likely attributed to the enhanced palatability and nutritional value of the TMR preserved by Selko-TMR.