Melkbaarheidsonderzoek bij het zwartbonte vee in Friesland
Various aspects of the ease of milking of more than a thousand cows were studied with a Gascoigne individual-quarter milking machine (pulsation ratio 3:1, pulsation rate 60 cycles per minute). Progeny groups from 17 bulls used in artificial insemination (420 heifers) were recorded twice and 75 cows on 9 different farms were tested on 16 occasions during lactation.Wide variation existed in peak flow (x = 2.13,σ= 0.70, C.V. = 33 %) and average flow (x = 1.70,σ= 0.58, C.V. = 34%). From paternal half-sib correlations, high heritability estimates of 0.65 ± 0.11 and 0.56 ± 0.10 were found for these features. Selection on peak flow could be especially effective. An accurate progeny test could be based on a sample of 25 daughters, while individual cows (bull dams) could be tested very accurately with 4 test milkings (repeatability 0.7). A correction for a standard milk yield of 7 kg was necessary for comparison.There was a sufficient variation in percentage milk in fore quarters x = 43.5,σ= 6.05, but heritability was lower (0.26 ± 0.28). No significant correlation was found with peak flow, machine time and quantity of stripping. Selection on this character was of minor importance.The average stripping yield by hand was 361 ml with wide variation, but very low heritability (0. 12 ± 0.24). Selection on this character was almost impossible.
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| Format: | Doctoral thesis biblioteca |
| Language: | Dutch |
| Published: |
Pudoc
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| Subjects: | animal husbandry, cattle, dairy breeds, friesland, netherlands, productivity, profitability, dierhouderij, melkveerassen, nederland, productiviteit, rentabiliteit, rundvee, |
| Online Access: | https://research.wur.nl/en/publications/melkbaarheidsonderzoek-bij-het-zwartbonte-vee-in-friesland |
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| Summary: | Various aspects of the ease of milking of more than a thousand cows were studied with a Gascoigne individual-quarter milking machine (pulsation ratio 3:1, pulsation rate 60 cycles per minute). Progeny groups from 17 bulls used in artificial insemination (420 heifers) were recorded twice and 75 cows on 9 different farms were tested on 16 occasions during lactation.Wide variation existed in peak flow (x = 2.13,σ= 0.70, C.V. = 33 %) and average flow (x = 1.70,σ= 0.58, C.V. = 34%). From paternal half-sib correlations, high heritability estimates of 0.65 ± 0.11 and 0.56 ± 0.10 were found for these features. Selection on peak flow could be especially effective. An accurate progeny test could be based on a sample of 25 daughters, while individual cows (bull dams) could be tested very accurately with 4 test milkings (repeatability 0.7). A correction for a standard milk yield of 7 kg was necessary for comparison.There was a sufficient variation in percentage milk in fore quarters x = 43.5,σ= 6.05, but heritability was lower (0.26 ± 0.28). No significant correlation was found with peak flow, machine time and quantity of stripping. Selection on this character was of minor importance.The average stripping yield by hand was 361 ml with wide variation, but very low heritability (0. 12 ± 0.24). Selection on this character was almost impossible. |
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