Effects of supplement feeding order on lactation, diurnal variation of ruminal ammonia and urea in the blood and milk of dairy cows

Abstract

The present study examined the effects of feeding order of grain and protein supplements on ruminal nitrogen (N) loss through the diurnal variation of ruminal ammonia N and urea N in the blood and milk of dairy cows. Three ruminally fistulated cows were used in a 3 ¥ 3 Latin square arrangement of treatments; that is, grain supplement fed at the first feed and then the protein supplement at the second (GS-1st), protein supplement fed first and then the grain supplement (PS-1st), and the grain and protein supplements mixed and divided into equal portions fed at each supplement feeding time (GP-mix). No differences in the lactation parameters were observed among the treatments. In GS-1st treatment, the increase in the concentration of ruminal ammonia N was inhibited after feeding, and the concentration was lower ( P < 0.05) than with the other treatments 1-2 h after basal feeding. The concentrations of urea N in the blood and milk with the GS-1st treatment were the lowest of all treatments throughout the sampling times, and were lower ( P < 0.05) than with the GP-mix treatment except for blood levels 1 h after basal feeding. The results suggest that grain feeding before protein feeding can reduce ruminal N loss.

Effect of the timing of sodium acetate infusion on the daily rhythms of milk synthesis and plasma metabolites and hormones in Holstein cows

“…Infusions of acetate or longchain FA decreased or did not change, respectively, the amplitude of the rhythm of BUN compared with CON when infused during the night, whereas protein infusions increased the amplitude of the rhythm (Salfer et al, 2019). The acrophase of BUN for all treatments agrees with previous reports (Gustafsson and Palmquist, 1993;Lefcourt et al, 1999;Ikuta et al, 2005). It is important to note that the magnitude of changes in the acrophase and the amplitude of the rhythms of BUN and MUN remained constant for all treatment, suggesting that they are at least partially responsive to each other.…”

Milk Urea Content and δ13C as Potential Tool for Differentiation of Milk from Organic and Conventional Low- and High-Input Farming Systems

“…It could be explained by the fact that feeding only by grass and forage compared to total mixed ration using, leads to protein-and carbohydrate-rich feed divided intake to a rumen. This causes rapid degradation of proteins in rumen and consequently increases the concentration of urea nitrogen in plasma and milk urea content which agrees with relevant studies (Ikuta et al, 2005;Geerts et al, 2004). In its turn, lack of energy for rumen microflora maintain caused by the absence of concentrates also leads to rumen nitrogen imbalance.…”

A review of factors influencing milk urea concentration and its relationship with urinary urea excretion in lactating dairy cattle

“…Based on the results of Gustafsson & Palmquist (1993) and Ikuta et al . (2005), MUN peaks c . 4 h after a meal.…”

“…Ikuta et al . (2005) supplemented half of the concentrates 30 min after feeding the basal diet, whereas the other half of the concentrates was supplemented 1·5 h after feeding the basal diet. The concentrates were separated into grain-rich and protein-rich parts.…”