Abstract
The aim of the study was to evaluate energy status of cows with different milk production during the first 100 days of lactation, based on the concentration of organic milk ingredients and ratio of urea and protein. The study included a total of 174 Holstein cows, divided into three groups based on daily milk yield (group A, n=15, bellow 20 litters, group B, n=64, from 20 to 30 litters, group C, n=95, above 30 litters). All cows were kept under usual farm conditions and fed diets adjusted to production category and period of the year. The concentration of milk fat declined with increasing daily milk production, while the concentration of urea had opposite trend. The concentrations of lactose and protein were the highest in the group B, while groups A and C had similar values. Statistically significant differences between all tested groups were found in concentrations of milk fat (4.28±0.56 versus 3.95±0.51 and 3.62±0.47 %, respectively), urea (2.81±0.32 versus 3.03±0.52, and 3.76±0.56 mmol/l, respectively), as well as the values of the concentrations of lactose and proteins between groups B and C (4.79±0.14 versus 4.73±0.13, and 3.10±0.21 versus 3.01±0.24 %). The distribution of values for the tested parameters within charts showing the relationships between urea and protein indicates a more or less pronounced energy deficit and the deficit or relative surplus of dietary protein in most of the cattle, which adversely affects their daily milk production and health.
Highlights
Intensive genetic selection and improvement of nutrition and care over the past several decades have led to a significant increase in milk yield per cow
Import of high genetic potential dairy cows during the last two decades did not provide satisfying results in increasing milk production in Republic of Srpska, primarily because it had not been accompanied by corresponding changes in feeding management, which resulted in earlier culling and insufficient use of their genetic potential
Considering that the shown values of concentration and the relationship of organic milk ingredients represent the average of a given group of cows, we have shown data for milk fat : protein ratio as well as urea: protein ratio graphically, to have insight into the overall state of supply of energy and protein at the group level
Summary
Intensive genetic selection and improvement of nutrition and care over the past several decades have led to a significant increase in milk yield per cow. This was contributed by serial of studies aimed to discovering new physiological mechanisms that influence the efficiency in milk production, as well as defining the influence of many factors on the expression of genetic potential in cows of high milk production. These studies pointed to the increased incidence of health. Import of high genetic potential dairy cows during the last two decades did not provide satisfying results in increasing milk production in Republic of Srpska, primarily because it had not been accompanied by corresponding changes in feeding management, which resulted in earlier culling and insufficient use of their genetic potential
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
