Continuous profiles and within-day variations of metabolites and hormones in cows fed diets varying in alimentary supplies before short-term feed deprivation.

Abstract

We investigated continuous profiles and within-day variations of some metabolites and hormones in four nonpregnant, nonlactating cows fed hay-based diets in two equal meals. Diets supplied either too much or too little N (approximately 1.3 or .8 times the maintenance requirements) and NE1 (approximately 1.2 or .8 times). Continuous collection of ruminal liquor, blood, and urine samples was performed for 42 consecutive hours, the last 16 h covering a period without feed. For twice-daily feeding, nitrogenous and energetic underfeeding decreased average ruminal propionate and the insulin:growth hormone ratio. However, only the energetic underfeeding increased plasma 3-methylhistidine and urinary excretion of 3-methylhistidine, and decreased body weight and ruminal acetate, butyrate, and total VFA. Conversely, only the nitrogenous underfeeding decreased glycemia. Whatever the dietary level, the 42-h patterns of metabolites and hormones were mainly affected by the time from the last meal. An energy deficit progressively took place during feed deprivation and the nocturnal interprandial period but not during the diurnal interprandial period. During the feed deprivation and nocturnal periods, glycemia was maintained despite a shortage in ruminal propionate. We conclude that in twice-daily fed cattle 1) the dietary supply of energy is the main trigger for an energy deficit and the subsequent muscle protein mobilization; 2) the nocturnal interprandial period may be considered as short-term feed deprivation; 3) the diurnal patterns of metabolites and hormones are not affected by the nitrogenous and(or) energetic supplies of the diet.

Effects of high ambient temperature and restricted feed intake on urinary and plasma 3‐methylhistidine in lactating Holstein cows

“…As summarized in Table 2, urinary 3MH excretion during days 10–14 of treatments was not different between treatments. However, Ndibualonji et al . (1997) showed that urinary 3MH excretion in non‐lactating cows was increased by 1.5‐fold during days 21–28 of treatments of energetic underfeeding.…”

“…Harris and Milne (1981) reported that intravenously administered radioactive 3MH was quantitatively excreted in cattle urine for 5–7 days. Ndibualonji et al . (1997) showed that urinary 3MH excretion and plasma 3MH concentration were increased during days 21–28 of an energetic underfeeding treatment, and indicated that endogenous protein mobilization was greater in energy‐restricted cows.…”

“…1998). Ndibualonji et al . (1997) reported that plasma 3MH in cattle was lower during the postprandial periods than during interprandial periods, and that the plasma 3MH concentration reflected the energetic level of the diet.…”

“…In addition, the concentration of plasma 3MH has been used as an index of myofibrillar protein degradation in dairy cows (Blum et al 1985), mouse (Yoshizawa et al 1997) and rat (Nagasawa et al 1998). Ndibualonji et al (1997) reported that plasma 3MH in cattle was lower during the postprandial periods than during interprandial periods, and that the plasma 3MH concentration reflected the energetic level of the diet. Therefore, when comparing the change of plasma 3MH concentration, blood samples must be withdrawn continuously during experimental periods or taken simultaneously.…”

Ruminal fermentation patterns and parameters of the acid base metabolism in the urine as influenced by the proportion of concentrate in the ration of dairy cows with and withoutFusariumtoxin-contaminated triticale

“…In the current study the moderate concentrations of SCFA in cows fed 60% concentrates (see Table 3) are probably related to the period of feed restriction discussed above. Ndibualonji et al (1997) examined the continuous profiles and within-day variations of SCFA in 4 non-lactating cows fed twice daily (6:15 a.m. and 3:30 p.m.). These authors observed that, with the beginning of a meal and over the next 6 hours (postprandial period), the ruminal SCFA increased.…”