scholarly journals Effects of Parity, Days in Milk, Milk Production and Milk Components on Milk Urea Nitrogen in Chinese Holstein

2010 ◽  
Vol 9 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Zhijun Cao ◽  
Wenming Huang ◽  
Tian. Wang ◽  
Yu Wang ◽  
Wan Wen ◽  
...  
Keyword(s):  
Milk Production ◽  
Urea Nitrogen ◽  
Chinese Holstein ◽  
Milk Components ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Breeding strategies to reduce environmental footprint in dairy cattle

2013 ◽  
Vol 4 (s1) ◽  
pp. 28-36 ◽  
Author(s):  
Donagh P. Berry
Keyword(s):  
Dairy Cattle ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Milk Production ◽  
Nitrogen Excretion ◽  
Environmental Footprint ◽  
Gas Emissions ◽  
Urea Nitrogen ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Animal breeding should be considered as a permanent and cumulative approach to reducing the environmental footprint of dairy cattle production systems within an overall national and global mitigation strategy. Current international dairy cattle breeding goals do not explicitly include environmental traits, but observed improvements in milk production and both fertility and longevity contribute substantially to improving the environmental footprint relative to output. Ideally, however, environmental related traits, most notably greenhouse gas emissions and nitrogen excretion, should be explicitly included in national breeding goals with their own economic weight. Access to routine phenotypic observations for the environmental traits or other information including genomic information or information on heritable correlated traits is required for inclusion in the selection index. There is, however, a considerable paucity of information on the genetic parameters for, in particular, greenhouse gas emissions in dairy cattle; these parameters include genetic variance estimates, as well as genetic and phenotypic (co)variances with other performance traits. Large studies with well phenotyped animals across a range of environments are needed to estimate such parameters and also investigate the extent, if any, of genotype-by-environment interactions across contrasting environments. Considerable genetic variation in milk urea nitrogen, as a proxy for nitrogen excretion in the urine, exist and suggest that breeding programmes to improve nitrogen use efficiency will be fruitful. However, because of the antagonistic genetic correlations between milk urea nitrogen and milk production, genetic gain in milk yield is expected to be compromised within a breeding goal that includes milk urea nitrogen.

scholarly journals Can Nitrogen Excretion of Dairy Cows Be Reduced by Genetic Selection for Low Milk Urea Nitrogen Concentration?

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 737
Author(s):  
Hewa Bahithige Pavithra Chathurangi Ariyarathne ◽  
Martin Correa-Luna ◽  
Hugh Blair ◽  
Dorian Garrick ◽  
Nicolas Lopez-Villalobos
Keyword(s):  
Positive Selection ◽  
Milk Production ◽  
Negative Selection ◽  
Selection Index ◽  
Nitrogen Excretion ◽  
N Leaching ◽  
Urea Nitrogen ◽  
Milk Urea ◽  
Selection For ◽  
Milk Urea Nitrogen

The objectives of this study were two-fold. Firstly, to estimate the likely correlated responses in milk urea nitrogen (MUN) concentration, lactation yields of milk (MY), fat (FY) and crude protein (CPY) and mature cow liveweight (LWT) under three selection scenarios which varied in relative emphasis for MUN; 0% relative emphasis (MUN0%: equivalent to current New Zealand breeding worth index), and sign of the economic value; 20% relative emphasis positive selection (MUN+20%), and 20% relative emphasis negative selection (MUN−20%). Secondly, to estimate for these three scenarios the likely change in urinary nitrogen (UN) excretion under pasture based grazing conditions. The predicted genetic responses per cow per year for the current index were 16.4 kg MY, 2.0 kg FY, 1.4 kg CPY, −0.4 kg LWT and −0.05 mg/dL MUN. Positive selection on MUN in the index resulted in annual responses of 23.7 kg MY, 2.0 kg FY, 1.4 kg CPY, 0.6 kg LWT and 0.10 mg/dL MUN, while negative selection on MUN in the index resulted in annual responses of 5.4 kg MY, 1.6 kg FY, 1.0 kg CPY, −1.1 kg LWT and −0.17 mg/dL MUN. The MUN−20% reduced both MUN and cow productivity, whereas the MUN+20% increased MUN, milk production and LWT per cow. Per cow dry matter intake (DMI) was increased in all three scenarios as milk production increased compared to base year, therefore stocking rate (SR) was adjusted to control pasture cover. Paradoxically, ten years of selection with SR adjusted to maintain annual feed demand under the MUN+20% actually reduced per ha UN excretion by 3.54 kg, along with increases of 63 kg MY, 26 kg FY and 16 kg CPY compared to the base year. Ten years of selection on the MUN0% index generated a greater reductions of 10.45 kg UN and 30 kg MY, and increases of 32 kg FY and 21 kg CPY per ha, whereas the MUN−20% index reduced 14.06 kg UN and 136 kg MY with increases of 32 kg FY and 18 kg CPY compared to base year. All three scenarios increased partitioning of nitrogen excreted as feces. The selection index that excluded MUN was economically beneficial in the current economic circumstances over selection indices including MUN regardless of whether selection was either for or against MUN. There was no substantial benefit from an environmental point of view from including MUN in the Breeding Worth index, because N leaching is more a function of SR rather than of individual cow UN excretion. This study demonstrates that attention needs to be paid to the whole system consequences of selection for environmental outcomes in pastoral grazing circumstances.

AGPAT3 Gene polymorphisms are associated with milk production traits in Chinese Holstein cows

2021 ◽  
pp. 1-6
Author(s):  
Xiaomei Sun ◽  
Yan Liang ◽  
Qisong Gao ◽  
Jiahe Guo ◽  
Cheng Tang ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Nucleotide Polymorphisms ◽  
Production Traits ◽  
Milk Production Traits ◽  
Fat Percentage ◽  
Urea Nitrogen ◽  
Protein Percentage ◽  
Milk Urea ◽  
Milk Urea Nitrogen

Abstract The current study reports the identification of previously undiscovered single-nucleotide polymorphisms (SNPs) in the bovine AGPAT3 gene and further investigates their associations with milk production traits. Our results demonstrate that the major allele C of the SNP g.12264 C > T is positively correlated with test-day milk yield, protein percentage and 305-day milk yield. Importantly, in silico analysis showed that the C/T transition at this locus gives rise to two new transcription factor binding sites (TFBS), E2F1 and Nkx3-2. Polymorphism g.18658 G > A was the only SNP associated with milk urea nitrogen (MUN) with the G allele related to an increase in milk urea nitrogen as well as fat percentage. The GG genotype of SNP g.28731 A > G was associated with the highest fat and protein percentage and lowest 305-day milk yield and somatic cell score (SCS). The association between AGPAT3 locus and milk production traits could be utilized in marker-assisted selection for the genetic improvement of milk production traits and, probably in conjunction with other traits, for selection to improve fitness of dairy cattle.

Factors affecting the milk urea nitrogen concentration in Chinese Holstein cows

2018 ◽  
Vol 68 (2) ◽  
pp. 193-211 ◽  
Author(s):  
Huimin Zhang ◽  
Mengqi Wang ◽  
Hongrui Jiang ◽  
Yan Cui ◽  
Hailei Xia ◽  
...  
Keyword(s):  
Protein Content ◽  
Nitrogen Concentration ◽  
Dairy Farm ◽  
Urea Nitrogen ◽  
Factors Affecting ◽  
Chinese Holstein ◽  
Chinese Holstein Cows ◽  
Milk Urea ◽  
Positive Correlations ◽  
Milk Urea Nitrogen

AbstractIn order to investigate the factors affecting milk urea nitrogen in Chinese Holstein cows, a large commercial dairy farm participated in a 30-month study. In this study, the mean milk urea nitrogen concentration was 11.75 mg/dl. The milk urea nitrogen reached its maximum value on day 90 of lactation for the first parity and the third or higher parities, but it peaked at the end of lactation for the second parity. The milk urea nitrogen of the first parity was lower than that of other parities. The milk urea nitrogen showed its minimum level in January, and reached its maximum in July. The milk urea nitrogen at the first month of lactation in cows calving in summer was higher than other seasons, while at the fourth month of lactation, the milk urea nitrogen of cows calving in autumn was significantly lower than in cows calving in other seasons. Positive correlations were observed between daily milk yield, net energy for lactation, crude protein and milk urea nitrogen for the first and third parities, but negative correlations were observed in the second parity. The milk urea nitrogen showed significantly positive correlations with fat content, total solid content and daily matter intake for all parities. A negative correlation was observed between milk urea nitrogen and protein content, with the exception of the second parity. For all data, as milk urea nitrogen concentration increased, milk protein content decreased. It has been recommended that milk urea nitrogen concentration should be evaluated in combination with parity, days in milk, season (or month), daily matter intake and dietary nutritional components, in order to improve the management and economic benefits of dairy farm.

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