How Do Today’s Dairy Cows Respond to an All-Herbage Ration?

Livestock Science, Article Number 104768

Agroscope investigated the effects on dairy cows of an all-herbage ration compared with a concentrate-supplemented ration. The study shows that an all-herbage ration is possible for suitable dairy cow types.

Compared to humans and other monogastrics like chickens and pigs, ruminants are particularly good at digesting high-fibre feedstuffs such as herbage. They are less good at utilising larger quantities of high-starch or high-sugar feedstuffs like cereals or many other concentrates, however. Despite this, 13% of global cereal production is fed as concentrates to ruminants, primarily cattle, which contributes either directly or indirectly to food shortages in some regions of the world. Increased milk and meat yields from cattle have led to an excessive use of potential foodstuffs, however. Further reasons cited for the use of concentrates in cattle production are the meeting of nutritional requirements and hence the maintenance of animal welfare, the balancing of the nutrient supply, the efficient utilisation of nutrients, and the reduction of emissions. Livestock farming should improve the net production of food for humans and hence make an essential contribution to food security.

All-herbage ration without concentrates compared with a supplemented ration

The aim of the study was to compare the effects of an all-herbage ration with nil kilograms of concentrates with the same herbage ration with 750 kg of concentrate supplement per cow and year. The effects on milk yield and composition, somatic cell counts, body condition, body weight, treatments and fertility in two Holstein cow types were investigated.

Over the three-year trial, a total of 138 lactations of 92 Holstein cows of Swiss (HCH) and New Zealand (HNZ) origin were examined. At the same time, the all-herbage or hay ration was compared with a diet in which 750 kg concentrates were additionally supplied during the first 300 days of lactation. Hay was fed during winter feeding, and the dairy cows grazed during summer feeding.

Cows on an all-herbage ration produced 5376 kg milk per year

With the additional 750 kg of concentrate the dairy cows produced more milk per standard lactation – around 1 kg milk per kg of additional concentrate – and they also produced more in relation to their body weight. In addition, the cows with concentrate supplementation had a somewhat higher body weight and a somewhat better body condition. Levels of the milk components fat, protein, lactose and urea as well as the somatic cell counts were comparable with and without concentrate supplementation.

Differences between the Holstein cow types

The HCHs produced more milk than the HNZs. Being bigger, however, they produced less milk per kilogram of body weight than the HNZs. Furthermore, the HCHs both with and without concentrate supplementation were too lean compared to the norm, as well as compared to the HNZs. Lastly, both cow types had similar milk-urea content and somatic cell counts. The HCHs received more medical treatments for fertility matters as well as overall than the HNZs. With regard to the medical treatments, it would appear that the appropriate cow type is more important than concentrate supplementation.