Nitrogen Balance, Microbial Protein Production, and Milk Production in Dairy Cows Fed Fodder Beets and Potatoes, or Barley

Abstract

Fourteen multiparous midlactation dairy cows were used in a change-over experiment with 3 periods and 3 diets to evaluate the effects of fodder beets and potatoes on N metabolism, microbial protein production, and milk production. A basal ration of alfalfa/grass silage offered ad libitum, 1 kg of grass hay and 1 kg of heat-treated rapeseed cake was supplemented with 5 kg DM of either rolled barley/raw potatoes 80:20 (BAP), fodder beets/raw potatoes 80:20 (BEP) or rolled barley (BA). Urine and feces were collected quantitatively from 8 cows and ruminal samplings, and evacuations were performed on 4 cannulated cows. Intake and production did not differ between BAP and BA, but the BEP diet lowered intake of both silage and total ration by 0.9 kg DM. Daily yield of energy-corrected milk (ECM) was decreased by 1.7 and 2.3 kg compared with BAP and BA, respectively. Milk urea concentration was 1 mM lower with the BEP diet. The proportion of feed N recovered in milk was 20 to 21% for all diets. With the BEP diet, urinary N amount and proportion were reduced correspondingly to the lower total N intake. Fecal N amount remained unchanged, and hence nitrogen apparent digestibility decreased by 5 percentage units with the BEP diet. Microbial protein production, assessed by allantoin excretion, tended to be highest with the BAP diet. Acetate proportion of VFA was lowered by the BEP diet, while proportions of propionate and butyrate both tended to increase. Different fermentation patterns, probably related to differences in rumen microbiota, could explain why changes in energetic efficiency and milk composition reported in the literature did not occur in the actual experiment when roots replaced barley. Compared with barley, roots appeared to have a greater negative effect on silage intake in conjunction with a prewilted silage with high intake potential allowed ad libitum and this decreased milk production by a magnitude corresponding to the lower intake of ME.

Effect of dietary starch source on milk production and composition of lactating Holstein cows

“…Non-fibre carbohydrates (NFC) may provide 30 to 45% of the diet on a dry matter (DM) basis (Hall et al, 2010). Root crops such as potato have been used in dairy rations, but have been replaced by grains and maize silage because of labour costs (Eriksson et al, 2004). Dairy cow diets usually contain barley, maize and wheat as the main carbohydrate sources because they are cost-effective sources of digestible energy.…”

Efeitos da adição de batata na silagem de capim-elefante sobre o consumo e a produção em vacas leiteiras

“…Segundo Fredeen (1996) e Peres Junior (2001), como regra geral, a concentração de lactose no leite não pode ser alterada por fatores nutricionais, portanto, não deve ser usada para o monitoramento nutricional de vacas leiteiras, a menos que os animais estejam muito subnutridos. Eriksson et al (2003) avaliaram o uso de beterraba forrageira, batata crua e cevada na alimentação de vacas leiteiras e observaram que, em comparação à associação de beterraba e batata, o fornecimento de cevada batata e cevada pura proporcionou a mais 1,7 e 2,3 litros de leite corrigido a 3,5% de gordura. As concentrações de gordura no leite, lactose e sólidos totais não foram alteradas pelo fornecimento das silagens de capim-elefante com batata, enquanto a de proteína no leite foi moderadamente mais elevada (P = 0,05) no tratamento com cevada.…”

The effect of supplementing highly wilted grass silage with maize silage, fodder beet or molasses on degradation of the diets and the efficiency of microbial protein synthesis in the rumen of sheep

“…Using an in vitro method, Eriksson et al (2004a) found that supplementation of GS with FB resulted in higher MPS and higher EMPS. However, the same authors were not able to confirm their in vitro results in an in vivo trial (Eriksson et al, 2004b). Some other traits that can indirectly indicate a beneficial effect of FB on rumen function can be found in the literature.…”