Dietary supplementation with N-carbamoylglutamate initiated from the prepartum stage improves lactation performance of postpartum dairy cows

Abstract

The objective of this study was to investigate the effects of supplementing N-carbamoylglutamate (NCG), an Arg enhancer, on amino acid (AA) supply and utilization and productive performance of early-lactating dairy cows. Thirty multiparous Chinese Holstein dairy cows were randomly divided into control (CON, n = 15) and NCG (CON diet supplemented with NCG at 20 g/d per cow, n = 15) groups at 4 wk before calving. Diets were offered individually in tie-stalls, and NCG was supplemented by top-dress feeding onto total mixed ration for the NCG group. The experiment lasted until wk 10 after calving. Dry matter intake tended to be higher ( P = 0.06), and yields of milk ( P < 0.01), milk protein ( P < 0.01), and milk fat ( P < 0.01) were higher in the NCG-cows than in the CON-cows. Plasma activities of aspartate aminotransferase ( P < 0.01), alanine aminotransferase ( P = 0.03), and plasma level of β-hydroxybutyrate ( P = 0.04) were lower in the NCG-cows than in the CON-cows, whereas plasma glucose ( P = 0.05) and nitric oxide (NO, P < 0.01) concentrations were higher. Coccygeal vein concentrations of Cys ( P < 0.01), Pro ( P < 0.01), Tyr ( P = 0.05), most essential AA except Thr and His ( P < 0.01), total essential AA ( P < 0.01), and total AA ( P < 0.01) were higher in the NCG-cows than in the CON-cows. The arterial supply of all AA was greater in the NCG-cows than in the CON-cows. The NCG-cows had higher mammary plasma flow of AA ( P = 0.04) and clearance rate of Cys ( P < 0.01), Pro ( P < 0.01) and Asp ( P < 0.01), and higher ratios of uptake to output of Met ( P = 0.05), Lys ( P < 0.01), Cys ( P = 0.01), Pro ( P = 0.03), and Asp ( P = 0.01). In summary, addition of NCG initiated from the prepartum period improved the lactation performance of postpartum dairy cows, which might attribute to greater Arg and NO concentrations, as well as improved AA supply and utilization, liver function, and feed intake in these cows.

Supplementing N-carbamoylglutamate in late gestation increases newborn calf weight by enhanced placental expression of mTOR and angiogenesis factor genes in dairy cows

“…In our previous companion study, dietary NCG supplementation increased the AA supply and improved the health status of transition dairy cows ( Gu et al, 2021 ). The nutrient supply and maternal health are closely related to fetal growth and development ( Tao et al., 2012 ).…”

“…The experimental procedures used in this study were approved by the Animal Care Committee of Zhejiang University (Hangzhou, China) and were conducted in accordance with the university's guidelines for animal research. The details for the experimental design were described previously ( Gu et al, 2021 ). In brief, 30 multiparous Chinese Holstein dairy cows with similar body weight (BW; 657 kg, SD = 58) at wk 4 before parturition were assigned to 15 blocks according to parity, 305-d milk yield (8,692 kg, SD = 607) of the previous lactation, BW, and body scores.…”

“…The parities were 2.80 (SD = 0.86) and 2.67 (SD = 0.81) in the CON and NCG groups, respectively. The chemical compositions of the diets are as described previously ( Gu et al, 2021 ). Throughout the trial period, cows were housed in a barn with individual tie stalls and had free access to water.…”

“…The globulin was obtained by subtracting albumin from total protein; thus all globulins were included in the measurement. The plasma AA compositions were determined as described previously ( Gu et al, 2021 ). Briefly, ice-cold sulfosalicylic acid (50 g/L) was added to the plasma (1:4, vol/vol) to precipitate the protein.…”

“…Recently, we reported that supplemental NCG in transitional dairy cows could increase the supply of Arg and improve the health and production performance of dairy cows ( Gu et al, 2021 ). In this companion study, we investigated the effects of supplementing NCG to dairy cows during late pregnancy on fetal growth, newborn calf weight, expression of nutrient transporters in uteroplacental tissue, and calf blood metabolites.…”