Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows
Most Swedish dairy cow’s life expectancy is five years, which is 2.5 lactations. The most common reason for dairy cows being culled are e.g. impaired fertility, mastitis, or low milk yield. Increased cow longevity is associated with animal welfare and would reduce the emission intensity per unit of...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
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SLU/Department of Molecular Sciences
2020
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| Materias: |
| _version_ | 1855572697925287936 |
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| author | Apelthun, Gabriella |
| author_browse | Apelthun, Gabriella |
| author_facet | Apelthun, Gabriella |
| author_sort | Apelthun, Gabriella |
| collection | Epsilon Archive for Student Projects |
| description | Most Swedish dairy cow’s life expectancy is five years, which is 2.5 lactations. The most common reason for dairy cows being culled are e.g. impaired fertility, mastitis, or low milk yield. Increased cow longevity is associated with animal welfare and would reduce the emission intensity per unit of milk solids per cow. The objective of this study was to investigate the differences in raw milk quality (e.g. composition, SCC, pH, and plasmin- and plasminogen derived activity) and processability of milk (e.g. curd yield, ethanol stability, gel firmness, rennet coagulation time) from cows with different number of lactations, i.e. old cows compared to young cows, and breeds. Milks samples from SRB and SLB cows were collected for this study, eight from each breed. Milk from young SLB cows, had a significant harder gel firmness and shorter rennet coagulation time compared to milk from older cows, however, it was not observed within milk from SRB cows. Within SRB, the difference in SCC was significant between milk from older and younger cows. There was no significant difference in ethanol stability between lactation numbers, but SLB had significantly higher ethanol stability compared to SRB. In milk from SRB cows, the content of βA1-caseins was significantly higher than in milk from SLB cows, whereas SLB milk had significantly higher content of βA2-caseins. Further research with repeated analysis and more individuals is required, to be able to make any conclusions on how the number of lactations of cows affect the processability and quality of milk. |
| format | H2 |
| id | RepoSLU16140 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2020 |
| publishDateSort | 2020 |
| publisher | SLU/Department of Molecular Sciences |
| publisherStr | SLU/Department of Molecular Sciences |
| record_format | eprints |
| spelling | RepoSLU161402020-10-08T01:01:56Z Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows Sammansättning och processegenskaper hos mjölk från äldre kor : en pilotstudie om skillnader i mjölkkvalitet mellan unga och äldre kor Apelthun, Gabriella Raw milk quality lactation number gel firmness rennet coagulation time Swedish Holstein Swedish Red Most Swedish dairy cow’s life expectancy is five years, which is 2.5 lactations. The most common reason for dairy cows being culled are e.g. impaired fertility, mastitis, or low milk yield. Increased cow longevity is associated with animal welfare and would reduce the emission intensity per unit of milk solids per cow. The objective of this study was to investigate the differences in raw milk quality (e.g. composition, SCC, pH, and plasmin- and plasminogen derived activity) and processability of milk (e.g. curd yield, ethanol stability, gel firmness, rennet coagulation time) from cows with different number of lactations, i.e. old cows compared to young cows, and breeds. Milks samples from SRB and SLB cows were collected for this study, eight from each breed. Milk from young SLB cows, had a significant harder gel firmness and shorter rennet coagulation time compared to milk from older cows, however, it was not observed within milk from SRB cows. Within SRB, the difference in SCC was significant between milk from older and younger cows. There was no significant difference in ethanol stability between lactation numbers, but SLB had significantly higher ethanol stability compared to SRB. In milk from SRB cows, the content of βA1-caseins was significantly higher than in milk from SLB cows, whereas SLB milk had significantly higher content of βA2-caseins. Further research with repeated analysis and more individuals is required, to be able to make any conclusions on how the number of lactations of cows affect the processability and quality of milk. De flesta mjölkkor i Sverige har en förväntad livslängd på 5 år, vilket motsvarar 2,5 laktationer. Den vanligaste orsaken till att mjölkkor slaktas är bl. a. försämrad fertilitet, mastit eller låg mjölkproduktion. En ökad livslängd hos kor förknippas med ökad djurvälfärd och skulle också bidra till en minskning av växthusgasutsläppen per enhet mjölk torrsubstans per ko. Syftet med denna studie var att undersöka skillnader i mjölkråvarans kvalitet (dvs. sammansättning, SCC, pH, plasmin– och plasminogen erhållen aktivitet) och mjölkens processegenskaper (dvs. etanol stabilitet, gelstyrka, koaguleringstid, ostutbyte) hos kor med olika antal laktationer (unga och gamla) och ras. SRB och SLB kor valdes ut för att delta i studien, åtta från varje ras. I mjölk från SLB kor var skillnaden i gelstyrka och koaguleringstid signifikant mellan mjölk från äldre och yngre kor, dock var skillnaden inte signifikant för mjölk från SRB kor. Skillnaden i SCC mellan mjölk från äldre och yngre kor var signifikant hos mjölk från SRB. Det fanns ingen signifikant skillnad mellan antal laktationer och etanol stabilitet, däremot hade SLB signifikant högre etanol stabilitet jämfört med SRB. Ett signifikant högre innehåll av βA1-kasein noterades i SRB, medan SLB hade signifikant högre innehåll av βA2-kasein. Ytterligare studier med fler individer och upprepade analyser krävs för att kunna göra någon signifikant slutsats av hur antalet laktationer påverkar mjölkens sammansättning och processegenskaper. SLU/Department of Molecular Sciences 2020 H2 eng swe https://stud.epsilon.slu.se/16140/ |
| spellingShingle | Raw milk quality lactation number gel firmness rennet coagulation time Swedish Holstein Swedish Red Apelthun, Gabriella Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title | Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title_full | Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title_fullStr | Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title_full_unstemmed | Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title_short | Composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| title_sort | composition and processability of milk from older cows : a pilot study on milk quality differences between young and old cows |
| topic | Raw milk quality lactation number gel firmness rennet coagulation time Swedish Holstein Swedish Red |