Onderwerp scriptie

Interactions between dry period length, energy balance and behaviour in dairy cows - Pieternel van der Spek

The severe negative energy balance in early lactation could reduce the welfare of a cow. A shorter or no dry period reduces the negative energy balance, and could thus be expected to improve welfare. Behavioural changes can be used as an indicator for welfare, because discomfort and diseases can change behaviour. Lying and feeding behaviour after different dry period lengths were used to gain insight in the impact of the dry period length and negative energy balance on cow welfare.

Milk yield, energy balance, dry matter intake, lying and feeding behaviour were measured for cows with no (n=80) or a short dry period (n=42). Before calving, cows with a 30-d dry period spent more time on lying, took less steps and had a lower speed of feed intake than cows without a dry period. After calving, cows without a dry period had a shorter and less severe negative energy balance than cows with a dry period of 30 days. The better energy balance was caused by a lower milk production and a higher feed intake. Cows with a dry period of 30 days spent less time on lying, took the same amount of steps and had still a lower speed of feed intake than cows without a dry period. Overall, cows with a dry period of 30 days showed larger behavioural differences comparing before and after calving than cows without a dry period.

These behavioural differences might indicate that cows with a dry period need more time in adapting to the new lactation than cows without a dry period. Also, they are facing acute stress moments at drying off and at the start of the lactation, and they experience more chronic stress than cows without a dry period due to the longer and more severe negative energy balance after calving. Overall, welfare in the aspect of affective state seems to be lower for cows with a dry period of 30 days compared to cows without a dry period.

Student: P van der Spek

Supervisor: A Kok, MSc

36 Ects