Original scientific paper
https://doi.org/10.5513/JCEA01/17.4.1830
Changes of fat-to-protein ratio from start to the midlactation and the impact on milk yield
Michal VLČEK
; Slovak University of Agriculture in Nitra, Department of Animal Genetics and Breeding Biology, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic
Július ŽITNÝ
; Slovak University of Agriculture in Nitra, Department of Animal Genetics and Breeding Biology, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic
Radovan KASARDA
; Slovak University of Agriculture in Nitra, Department of Animal Genetics and Breeding Biology, Tr. A. Hlinku 2, 949 76 Nitra, Slovak Republic
Abstract
The aim of the study was to evaluate the changes of fat-to-protein ratio (F/P ratio) from early to mid-lactation and the impact on milk yield. 208 Holstein cows from 3 dairy farms in west Slovakia calved between years 2012 and 2015 were observed. Into the study 908 test-day records of milk yield were included. Cows were from 5 to 150 days in milk (DIM). Statistical analysis and analysis of influence of F/P ratio on milk yield were performed by SAS. The sample of observed cows produced 35.25 ± 11.55 kg*day-1 of milk. The average day in milk was 77.40 ± 41.17 and the average F/P ratio was 1.19 ± 0.25. In acidosis risk were 19.71% of all observation and 8.92% were in ketosis risk. The occurrence of acidosis risk increased and the occurrence of ketosis risk decreased from early to mid-lactation. The model described the variation of milk yield by 44.20%. All of the selected effects except the year of calving had high statistical significant (P<0.01) influence to variation of milk yield. The effect of F/P ratio decreased the milk yield by 4.97 kg*day-1. The highest impact of F/P ratio was observed between 5 and 30 DIM and decreased the milk yield by 6.31 kg*day-1. The average F/P ratio of observations between 5 and 30 DIM was 1.32 ± 0.30. The smallest impact of F/P ratio was found between 61 and 90 DIM and decreased the milk yield by 3.74 kg*day-1. The average F/P ratio of observation between 61 and 90 DIM was 1.16 ± 0.22. It is possible to use F/P ratio as non-invasive indicator of metabolic status to decrease the negative impact to milk yield.
Keywords
fat-to-protein ratio; Holstein cows; metabolic disorder; test-day
Hrčak ID:
170856
URI
Publication date:
16.12.2016.
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