Production of Hay milk

Summary

The investigation carried out in this thesis is based on data collected on three organic dairy farms in southern Jutland in Denmark. Two of these farms supplied feedstuff analyses of their hay, and one additional farmer besides these three took part in an interview on their use of hay feeding and production of haymilk.
The sale of dairy products made of haymilk has increased substantially in Austria over the past few years to 4,200 tons of cheese sold in 2011. Haymilk based dairy products are currently being sold in Germany and the interest is increasing in Switzerland. 83 tons of haymilk based cheeses were sold in Denmark in 2011, and there appears to be a market potential haymilk based dairy products in Denmark. The main objective of this thesis was to improve the decision basis for farmers considering switching from silage feeding to hay feeding of their lactating dairy cows.
A semi-structured group interview with four haymilk producing farmers showed that they had been inspired by other farmers abroad, who produce haymilk, and motivated by a belief in hay being healthier for their cows as well as the ability to obtain a premium for their milk. The interview furthermore showed that their workload was increased in summer and decreased in winter, although the overall workload was more enjoyable now.
No clear effect of conservation method on chemical composition of hays and silages were found, although a trend for lower CP and higher NDF content per kg of DM were seen in hay compared with silage. Structural properties measured with peNDF and CT was found to be more related to TCL and season, which was indicated by cutting number, than used conservation method.
The analysis of lactation curves, which was based on data obtained from three of the haymilk producing farmers, showed that DH cows in parity one and parity three or greater had achieved a higher persistency by switching to hay feeding, albeit their peak yields were reduced with 1.1 and 0.4 kg ECM per day respectively. No difference was found for DH cows in parity two and Jersey cows in parity one and parity two, but Jersey cows in parity three or greater had their peak yield reduced by 1.1 kg ECM per day. Fat and protein percentage increased for DH cows in parity one and parity three or greater. Protein percentage furthermore increased for Jersey cows in parity one whereas no difference was found for the other groups of cows.
The feeding software NorFor predicted hay fed cows to have a lower DMI and ECM production per day when compared with silage fed cows. This clear effect could not be confirmed in the literature as both an increasing and decreasing as well as an unchanged effect was seen. The somatic cell count was decreased for all groups of cows by switching to hay feeding except for DH cows in parity three or greater, which increased, and DH cows in parity one where no difference was found.
The cost of producing one FU of hay was estimated to be 0.70 kroner larger compared with silage (2.77 versus 2.07 kroner per FU). This resulted in a difference in feed cost between 0.19 and 0.56 kroner per kg ECM depending on the ration and the assumed effect of switching to hay feeding on DMI and daily ECM production. The simulated difference between hay and silage feeding was between a loss of 0.01 and a gain of 0.04 kroner per kg ECM across six scenarios tested on seven different types of herds or between -161 and 450 kroner per annual cow.