Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar
Milkability or ease of milking, has higher importance today for Swedish dairy cattle producers after the introduction of milking parlours and automatic milking systems. Milkability is the cow's ability to quickly milk out and be completely milked. There are several measures of milkability available....
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| Formato: | Otro |
| Lenguaje: | sueco sueco |
| Publicado: |
2006
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/11097/ |
| _version_ | 1855571807240716288 |
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| author | Norgren, Anna |
| author_browse | Norgren, Anna |
| author_facet | Norgren, Anna |
| author_sort | Norgren, Anna |
| collection | Epsilon Archive for Student Projects |
| description | Milkability or ease of milking, has higher importance today for Swedish dairy cattle producers after the introduction of milking parlours and automatic milking systems. Milkability is the cow's ability to quickly milk out and be completely milked. There are several measures of milkability available. Today the farmer measures the traits subjectively in relation to the conformation scoring of the cow 30-270 days after her first calving. The trait is not included in the total merit indexes for cows or bulls in Sweden.
In some milking systems certain milkability traits can be measured automatically, for example maximum flow rate, milk yield and milkingtime. The purpose of this study was to study the variation in these milkability traits, estimate the repeatability and the heritability. The goal was to get an understanding of whether data from automatic milking systems can be used in future for evaluating breeding values for milkability traits.
The study covered 2437 cows of SRB and SLB from 20 herds. The two traits that were measured for milkability were the milkingtime and maximum flow rate. The results show that both traits had rather low heritability (0.05) and high repeatability (0.9). Therefore it should be enough with one or two measurements to get reliable results.
SLB had higher milk yield, higher maximum flow rate and shorter duration of milking period than SRB. Both breeds were within the limits for optimal milkability considered in earlier studies of the subject.
Breed, stage of lactation, calving month, milk yield, and herd all had significant effects on duration of the milking period, whereas lactation number and calving year did not. Breed, stage of lactation, calving year, milk yield and herd had significant effect on maximum flow rate but lactation number and calving month had no significant effect on the trait. There were also big differences between the herds in the study when the traits in the statistical model had been taken into consideration. This shows that environmental effects such as management and milking equipment have great importance for the milkability traits. |
| format | Otro |
| id | RepoSLU11097 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish swe |
| publishDate | 2006 |
| publishDateSort | 2006 |
| record_format | eprints |
| spelling | RepoSLU110972017-09-29T07:35:21Z https://stud.epsilon.slu.se/11097/ Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar Norgren, Anna Animal genetics and breeding Milkability or ease of milking, has higher importance today for Swedish dairy cattle producers after the introduction of milking parlours and automatic milking systems. Milkability is the cow's ability to quickly milk out and be completely milked. There are several measures of milkability available. Today the farmer measures the traits subjectively in relation to the conformation scoring of the cow 30-270 days after her first calving. The trait is not included in the total merit indexes for cows or bulls in Sweden. In some milking systems certain milkability traits can be measured automatically, for example maximum flow rate, milk yield and milkingtime. The purpose of this study was to study the variation in these milkability traits, estimate the repeatability and the heritability. The goal was to get an understanding of whether data from automatic milking systems can be used in future for evaluating breeding values for milkability traits. The study covered 2437 cows of SRB and SLB from 20 herds. The two traits that were measured for milkability were the milkingtime and maximum flow rate. The results show that both traits had rather low heritability (0.05) and high repeatability (0.9). Therefore it should be enough with one or two measurements to get reliable results. SLB had higher milk yield, higher maximum flow rate and shorter duration of milking period than SRB. Both breeds were within the limits for optimal milkability considered in earlier studies of the subject. Breed, stage of lactation, calving month, milk yield, and herd all had significant effects on duration of the milking period, whereas lactation number and calving year did not. Breed, stage of lactation, calving year, milk yield and herd had significant effect on maximum flow rate but lactation number and calving month had no significant effect on the trait. There were also big differences between the herds in the study when the traits in the statistical model had been taken into consideration. This shows that environmental effects such as management and milking equipment have great importance for the milkability traits. Mjölkbarhet har ökad betydelse idag för svenska mjölkproducenter i och med det ökade antalet kor i lösdriftsbesättningar och i automatiska mjölkningssystem (AMS). Mjölkbarhet är kons förmåga att snabbt släppa ner mjölk och bli urmjölkad. Idag finns ett flertal mått på mjölkbarhet och i avelsvärderingen uppskattas egenskapen subjektivt av lantbrukaren i samband med exteriörbedömningen av kon. För närvarande är inte mjölkbarhet en egenskap som ingår i tjur- eller koindexen. I några mjölkningssystem mäts olika mått på mjölkbarhet automatiskt, till exempel maximal flödeshastighet, mjölkmängd och mjölkningstid. Examensarbetet syftade till att studera variationen och reproducerbarheten för dessa mjölkbarhetsvariabler, samt hur stor den genetiska variationen är. Detta för att skapa en uppfattning om data från automatiska mjölkningssystem kan ligga till grund för avelsvärderingen samt hur ofta man behöver mäta. Undersökningen omfattade 2437 kor av raserna SRB och SLB från 20 stycken besättningar. De olika mätegenskaper som användes för mjölkbarhet var mjölkningstid samt mjölkflöde. Skattning av varianskomponenterna visade att mjölkflöde och mjölkningstid hade låga arvbarheter (ca 5%) men hög reproducerbarhet (ca 0,9). Denna arvbarhet är betydligt lägre än vad som skattats i andra studier. Eftersom sambandet är högt mellan två mätningar skulle det räcka med en eller två mätningar för dessa egenskaper. Ras, laktationsstadium, kalvningsmånad, mjölkmängd och besättning hade signifikant betydelse på mjölkningstid. Däremot hade laktationsnummer och år inte signifikant betydelse på mjölkningstid. Ras, laktationsstadium, kalvningsår, mjölkmängd och besättning hade signifikant betydelse för mjölkflöde medan laktationsnummer och kalvningsmånad inte hade det. Det var stor skillnad mellan besättningar även efter att hänsyn hade tagits till övriga faktorer i modellen. Detta visar att miljöeffekter såsom skötsel och utrustning har stor påverkan på de olika mjölkbarhetsegenskaperna. SLB hade högre mjölkmängd, högre mjölkflöde samt kortare mjölkningstid jämfört med SRB. Båda raserna låg dock inom gränserna för optimal mjölkbarhet enligt tidigare studier inom området. 2006-11-08 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/11097/1/norgren_a_170929.pdf Norgren, Anna, 2005. Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar. UNSPECIFIED, Uppsala. Uppsala: (VH) > Dept. of Animal Breeding and Genetics (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-670.html> urn:nbn:se:slu:epsilon-s-7280 swe |
| spellingShingle | Animal genetics and breeding Norgren, Anna Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title | Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title_full | Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title_fullStr | Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title_full_unstemmed | Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title_short | Studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| title_sort | studier av mjölkbarhet automatiskt mätt i mjölkningsanläggningar |
| topic | Animal genetics and breeding |
| url | https://stud.epsilon.slu.se/11097/ https://stud.epsilon.slu.se/11097/ |