scholarly journals STUDY ON THE INFLUENCE OF CERTAIN FACTORS ON THE MILK UREA CONTENT IN SHEEP FROM THE BULGARIAN SYNTHETIC MILK POPULATION

2020 ◽  
Vol 10 (1-2) ◽  
pp. 5-9
Author(s):  
Milena Mihaylova ◽  
Rumen Bazitov
Keyword(s):  
2019 ◽  
Vol 88 (3) ◽  
pp. 277-285
Author(s):  
Petra Timkovičová Lacková ◽  
Iveta Maskaľová ◽  
Vladimír Vajda

The aim of this study was to evaluate the milk urea content along with the dynamics of lactation and milk components in production dependency in Holstein dairy cows. Evaluation of daily milk yield in relation to milk urea presented a positive regression dependency, which was the strongest in early lactation (r = 0.860; P < 0.001), decreasing in mid lactation (r = 0.329; P < 0.001) and late lactation (r = 0.261; P < 0.001). Evaluation of milk protein in relation to milk urea showed a negative regression dependency, which was the strongest in early lactation (r = -0.850; P < 0.001), decreasing in mid lactation (r = -0.819; P < 0.001) and late lactation (r = -0.679; P < 0.001). The somatic cell counts in relation to milk urea confirmed a negative regression dependency in early lactation (r = -0.635; P < 0.05) and mid lactation (r = -0.818; P < 0.05), but no significance was found in late lactation. The results of the study confirm the influence of production factors (milk quantity and milk components) on the milk urea content. Dependencies found between the production, milk components and milk urea are applicable for the evaluation of protein nutrition and metabolic transformation of nutrients in dairy cows.


1997 ◽  
Vol 77 (4) ◽  
pp. 505-514 ◽  
Author(s):  
B. Martin ◽  
J. B. Coulon ◽  
J. F. Chamba ◽  
C. Bugaud
Keyword(s):  

1999 ◽  
Vol 1999 ◽  
pp. 68-68 ◽  
Author(s):  
B.R. Cottrill ◽  
H. Biggadike ◽  
C.A. Collins ◽  
S.B. Drew

A number of studies have shown that milk urea levels above about 350 mg/l are associated with reduced fertility in dairy cows (Ropstad and Refsdal, 1987; Gustafsson and Carlsson, 1993). A significant and increasing proportion of UK milk producers receive regular information on the urea content of bulk milk as part of routine milk testing. Two studies were undertaken to examine whether the urea content in bulk milk (Study 1) or in milk from individual cows at about the time of service (Study 2) could be used as a management aid to improve fertility status.In Study 1, the milk urea (MU) contents in bulk milk samples from 475 farms in England and Wales were determined by NIRS. Fertility data for each farm was obtained from National Milk Records. Analysis of the data for each month of the study was restricted to those herds in which ≥15 cows were served.


2016 ◽  
Vol 12 (3) ◽  
pp. 21-32
Author(s):  
Alicja Satoła ◽  
Ewa Ptak

The objective of the study was to determine the relationships between milk urea concentration and factors such as lactation number, stage of lactation, month and season of the test day, age at calving, milk yield and protein percentage. Data for the calculations consisted of 7,731 test-day records from 1,078 Polish Holstein-Friesian cows. Test-day milking was performed for first, second and third lactations during the period from December 2010 to December 2011. Calculations were performed using the MIXED procedure in SAS/STAT. A mixed linear model using was applied in which parameters were estimated by the restricted maximum likelihood (REML) method. Least squares means for fixed eff ects in the model were compared by the Tukey-Kramer test. The first lactation diff ered significantly (p<0.05) from the second and third in terms of mean urea concentration, but there were no significant diff erences between the second and third lactations. For primiparous cows the milk urea concentration increased throughout lactation, but for older cows it increased only up to 7–8 months of lactation. Urea concentrations did not diff er significantly in the same stages of consecutive lactations, i.e. the first and second or second and third. Statistically significant diff erences were noted between the first and third lactations only in months 9 and 10 of lactation. Seasonal changes in milk urea content varied depending on the lactation number. In the first lactation the milk urea concentration was lowest in spring and highest in autumn. This tendency was not observed in the second and third lactation. Milk urea concentration was positively associated with both milk yield and protein percentage


Author(s):  
Yaroslava Zhukova ◽  
Pylyp Petrov ◽  
Yuriy Demikhov ◽  
Alex Mason ◽  
Olga Korostynska

The influence of farming type (conventional or organic) and production system (low-and high-input) on various quality characteristics of milk have been in the focus of studies over the last decade. The aim of this work was to evaluate the impact of different dairy management and production systems on carbon stable isotopes ratio (δ13C) and milk urea content. The samples of raw milk were collected each two weeks at certified organic high-input and low-input farms, conventional high-input and low-input farms in late indoor period and outdoor period. Data analysis showed clear difference between milk from organic high- and low-input farms with non-overlapping range between -22.90 ‰ and -24.70‰ for δ13С in protein fraction (equal 1.80‰) and between -25.90‰ and -28.20‰ (equal 2.30‰) for δ13С in fat fraction independently from season factor, as for Δδ13С (protein-fat) values in milk from high-input (1.50-3.00‰) and low-input (3.20-6.30‰) organic farms. Analysis of correlation between δ13С in protein fraction and milk urea content values showed that during late indoor period the most significant difference was detected between milk from organic low-input and conventional high-input farms (5.85‰ for δ13С in protein fraction and 4.65 mg/100 g of milk urea content). During outdoor period, the non-overlapping range was established for low-input and high-input organic farms (3.40‰ for δ13С in protein fraction and 10.77 mg/100 g of milk urea content). Results of δ13С values in fat and protein milk fractions, as combination of δ13С in protein fraction and milk urea content could be a potential tool for the distinguish of milk from different farming types, based on different feed composition.


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