Phenotypic performance and heritability of milk yield and its component traits of two types of Holstein German cattle. | ||||
| Minia Journal of Agricultural Research and Development | ||||
| Volume 44, Issue 3, September 2024, Page 453-464 PDF (1.18 MB) | ||||
| Document Type: Original Articles | ||||
| DOI: 10.21608/mjard.2024.378202 | ||||
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| Abstract | ||||
| In the current study, traits of milk yield (total milk yield: MY in Kg. and daily milk yield: DMY in Kg.) and its components such as fat percent (F%), fat yield in Kg (FY), protein percentage (P%), Protein yield (PY) in kg. and fat/protein ratio (F/P) were analyzed to evaluate the phenotypic performance and heritability in five parities of both black Holstein-Schwarzer Bunt Type: Sbt and red Holstein- Bunt Type: Rbt Germany cattle. The milk yield and its component traits showed high significant variation between the two German Holstein types and among different parities, as well as the interaction between them. It is clearly seen that the mean values of 4th lactation period for MY, DMY, F%, FY, P %, PY and F/P ratio were the highest among parities. Data of correlation between milk yield (MY) and its components showed negative correlation between the milk yield on one side and fat percent, protein percent and fat/ protein ratio on the other side, while positive correlation is found between milk yield in Kg. , fat and protein yield in Kg., in both Sbt and Rbt types. Data showed that except the milk protein yield in Kg., the heritability (H2) values of all studied milk traits of Sbt are higher than those of Rbt type. Fat% exhibited the highest H2 values than those of almost all studied milk traits of both Sbt and Rbt, whereas the H2 values of fat yield of both Sbt and Rbt are the lowest. It should be noted that H2 values of milk protein percentage are relatively high. | ||||
| Keywords | ||||
| correlation; Milk yield; milk components; heritability | ||||
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