Whole-tract digestibility and nitrogen-use efficiency of partial mixed rations with and without canola meal

2017 ◽  
Vol 57 (7) ◽  
pp. 1398
Author(s):  
V. M. Russo ◽  
L. C. Marett ◽  
M. M. Wright ◽  
M. J. Auldist ◽  
W. J. Wales
Keyword(s):  
Milk Production ◽  
Nitrogen Use Efficiency ◽  
Crude Protein ◽  
Experimental Period ◽  
Canola Meal ◽  
Nitrogen Use ◽  
Dietary Nitrogen ◽  
Increase Milk Production ◽  
Use Efficiency ◽  
Grazing Dairy Cows

Increasing the crude protein (CP) concentration of a ration fed to grazing dairy cows by adding canola meal can increase milk production. The present study investigated the effect of extra CP intake on nitrogen-use efficiency and the fate of the additional dietary nitrogen (N). Sixteen spring-calved rumen fistulated cows were housed in metabolism stalls for a 9-day period and offered one of the following four treatment diets: (1) 8 kg DM/cow.day of fresh perennial ryegrass (PRG) supplemented with 12 kg DM/cow.day of a partial mixed ration (PMR) comprising oaten hay, crushed maize and wheat grain (PMR 8); (2) 12 kg DM/cow.day of fresh-cut PRG and 12 kg DM/cow.day of PMR (PMR 12); (3) the same as for PMR 8 cows, except some wheat in the PMR was replaced with canola meal (PMR+C 8); and (4) the same as the PMR 12 cows, except some wheat in the PMR was replaced with canola meal (PMR+C 12). The PMR and the PMR+C diets were iso-energetic, but the canola meal provided extra CP. Crude protein intake was 14.4%, 14.8%, 16.8% and 17.4% DM for PMR 8, PMR 12, PMR+C 8 and PMR+C 12 respectively. The addition of canola meal increased DM intake (P < 0.05) from 20.4 to 21.6 kg/day and increased N intake (P < 0.001) from 478 to 590 g/day. Nitrogen digestibility increased (P < 0.05) from 67% to 71%, nitrogen-use efficiency decreased (P < 0.05) from 37% to 32% and urinary-N output increased (P < 0.01) from 118 to 160 g/day, indicating that the additional CP fed resulted in additional N surplus. Energy-corrected milk yield for the experimental period was 34 ± 3.1 kg/cow.day (mean ± s.d.); however, due to the low number of cows, the ability to rigorously assess the effects on milk production was limited.

RESPONSE OF DAIRY COWS TO FORMALDEHYDE-TREATED CANOLA MEAL DURING EARLY LACTATION

1983 ◽  
Vol 63 (4) ◽  
pp. 905-915 ◽  
Author(s):  
R. C. RAE ◽  
J. R. INGALLS ◽  
J. A. McKIRDY
Keyword(s):  
Amino Acids ◽  
Milk Production ◽  
Plasma Levels ◽  
Experimental Period ◽  
Essential Amino Acids ◽  
Milk Composition ◽  
Canola Meal ◽  
Plasma Urea ◽  
Increase Milk Production ◽  
Isocaloric Diets

Forty Holstein cows were assigned to one of four isocaloric diets 2 wk postpartum in a 2 × 2 factorial arrangement. Factor I was dietary crude protein (CP) level, either 17.4% or 14.6% CP. Factor II was formaldehyde (FA) treatment of canola meal, either treated or untreated. The experimental period lasted 12 wk. Treatment with FA had no effect on milk yield, milk composition, dry matter (DM) intake or on apparent digestibilities of DM, nitrogen (N) or acid detergent fiber (ADF). FA treatment reduced ammonia-N (NH3-N) levels in rumen liquor (P < 0.05), tended to increase (P < 0.1) plasma levels of total essential amino acids and had no effect on plasma urea. High dietary CP increased (P < 0.05) milk and lactose yields, had no effect on rumen liquor NH3-N levels and increased (P < 0.05) plasma levels or urea and total essential amino acids. Treatment with FA appears to have increased absorption of total essential amino acids from the gut but did not increase milk production. Possibly, amino acid supply to the mammary gland did not limit milk synthesis in this experiment. Alternatively, FA treatment may have failed to increase absorption of the amino acids whose availability did limit milk synthesis. FA treatment apparently destroyed 58% of canola meal tyrosine and 29% of the lysine and this may be partially responsible for the lack of a response in milk production. Key words: Holstein, formaldehyde, canola meal, milk production, protein level, amino acids

scholarly journals Reduction of crude protein in diets fed to lactating Holstein-Gyr cows

2018 ◽  
Vol 53 (7) ◽  
pp. 858-865
Author(s):  
Clóvis Ribeiro Guimarães ◽  
Rafael Alves de Azevedo ◽  
Mariana Magalhães Campos ◽  
Fernanda Samarini Machado ◽  
Alexandre Mendonça Pedroso ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Crude Protein ◽  
Dry Matter ◽  
Nutrient Digestibility ◽  
Nitrogen Excretion ◽  
Productive Performance ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

Abstract: The objective of this work was to evaluate the effect of reducing crude protein (CP) contents in diets with a constant metabolizable protein content on the intake, performance, nitrogen balance, and nutrient digestibility of lactating Holstein-Gyr cows. Animals (n = 24, 103±23 days in milk) were allocated to four treatments (n = 6 per group) with different CP contents: 127, 132, 139, and 156 g kg-1 dry matter (DM). DM intake was not affected by treatments. CP intake and digestibility increased linearly with higher CP contents. Milk yield (23.7±3 kg per day) and the percentages of milk protein (3.3±0.2%) and fat (3.8±0.5%) were not affected by CP reduction. Milk and blood urea nitrogen increased linearly with the increase of CP in the diet, similarly to urinary nitrogen excretion. Nitrogen use efficiency was 29.8 and 22.4% when CP was 127 and 156 g kg-1 DM, respectively. Reducing CP in diets fed to mid-lactating Holstein-Gyr cows increases nitrogen use efficiency and maintains the productive performance of the cows.

scholarly journals Opportunities for Increased Nitrogen Use Efficiency in Wheat for Forage Use

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1738
Author(s):  
Nirmal Sharma ◽  
Raquel Schneider-Canny ◽  
Konstantin Chekhovskiy ◽  
Soonil Kwon ◽  
Malay C. Saha
Keyword(s):  
Nitrogen Use Efficiency ◽  
Crude Protein ◽  
Nitrogen Nutrition ◽  
N Uptake ◽  
N Fertilization ◽  
Shoot Biomass ◽  
Total Biomass ◽  
Strong Positive Correlation ◽  
Nitrogen Use ◽  
Use Efficiency

Wheat is a major cool-season forage crop in the southern United States. The objective of this study is to understand the effect of nitrogen (N) fertilization on wheat biomass yield, quality, nitrogen use efficiency (NUE), and nitrogen nutrition index (NNI). The experiments were conducted in a greenhouse and a hoop house in a split-plot design, with three replications. Twenty wheat cultivars/lines were evaluated at four N rates (0, 75, 150, and 300 mg N.kg−1 soil) in the greenhouse and (0, 50, 100, and 200 mg N.kg−1 soil) in the hoop house. In general, high-NUE lines had lower crude protein content than the low-NUE lines. None of the cultivars/lines reached a plateau for biomass production or crude protein at the highest N rate. The line × N rate interaction for NUE was not significant in the greenhouse (p = 0.854) but was highly significant in the hoop house (p < 0.001). NNI had a negative correlation with NUE and biomass. NUE had strong positive correlations with shoot biomass and total biomass but low to moderate correlations with root biomass. NUE also had a strong positive correlation with N uptake efficiency. Lines with high NUE can be used in breeding programs to enhance NUE in wheat for forage use.

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