Freezing point of milk in a herd of high yielding dairy cows
Factors affecting the freezing point of milk in a herd of 200 Black and White cows with the average milk yield of 8 386 kg in the lactation and 8 328 kg in the standard lactation were examinated. Over the period of one year (2002) and based upon 1 773 individual monthly collected milk samples with t...
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Croatian Dairy Union
2005-04-01
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| Series: | Mljekarstvo |
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| Online Access: | http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=3972 |
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| author | Slavica Golc Teger Andrej Lavrenčić Aša Grahelj |
| author_facet | Slavica Golc Teger Andrej Lavrenčić Aša Grahelj |
| author_sort | Slavica Golc Teger |
| collection | DOAJ |
| description | Factors affecting the freezing point of milk in a herd of 200 Black and White cows with the average milk yield of 8 386 kg in the lactation and 8 328 kg in the standard lactation were examinated. Over the period of one year (2002) and based upon 1 773 individual monthly collected milk samples with the average contents of 3.91% fat, 3.26% protein, 4.54% lactose, 33.4 mg/100 ml urea and 331000 somatic cells per ml in milk were determined. The average freezing point of milk (n = 1 680) was estimated to be –0.527 ºC, with a range from -0.562 ºC to -0.423 ºC. In 210 (12.5%) samples was higher than -0.515 ºC. The lowest freezing point (-0.532 ºC) was found in the samples collected in the first month after calving and highest (-0.522 ºC) in the samples of 12th month of lactation. The differences between the freezing point of milk after the first and the second calving (-0.530 ºC; P < 0.05) and those after the fifth calving (-0.523 ºC; P < 0.05) were also significant. The samples collected in month from January to April (-0.538 ºC to -0.532 ºC) were significantly lower in comparison to samples collected in May and June (-0.517 ºC and -0.519 ºC). The following statistically significant correlation coefficients between cows' properties, milk composition and the freezing point of milk were found: month of lactation r = 0.233 (P < 0.001); lactation number r = 0.196 (P < 0.001); age of cows (years) r = 0.231 (P < 0.001); month of the year r = 0.0253 (P < 0.001); milk yield per milking day r = -0.106 (P < 0.001); fat corrected milk content (FCM) per milking day r = -0.234 (P < 0.001); lactose % r = -0.530 (P < 0.001); fat % r = -0.351 (P < 0.001); protein % r = 0.058 (P < 0.05); urea mg/100 mL r = 0.091 (P < 0.001) and somatic cell count r = 0.154 (P < 0.001). The sum of effects (month of the year, lactation lenght and fat, protein and lactose content of milk) was found to account for about 70% variability of the total depression of milk freezing point (R2 = 0.698). |
| format | Article |
| id | doaj-art-2d46e03507124c3e94f447aede4e35c4 |
| institution | OA Journals |
| issn | 0026-704X 1846-4025 |
| language | English |
| publishDate | 2005-04-01 |
| publisher | Croatian Dairy Union |
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| series | Mljekarstvo |
| spelling | doaj-art-2d46e03507124c3e94f447aede4e35c42025-08-20T02:01:34ZengCroatian Dairy UnionMljekarstvo0026-704X1846-40252005-04-01552125138Freezing point of milk in a herd of high yielding dairy cowsSlavica Golc TegerAndrej LavrenčićAša GraheljFactors affecting the freezing point of milk in a herd of 200 Black and White cows with the average milk yield of 8 386 kg in the lactation and 8 328 kg in the standard lactation were examinated. Over the period of one year (2002) and based upon 1 773 individual monthly collected milk samples with the average contents of 3.91% fat, 3.26% protein, 4.54% lactose, 33.4 mg/100 ml urea and 331000 somatic cells per ml in milk were determined. The average freezing point of milk (n = 1 680) was estimated to be –0.527 ºC, with a range from -0.562 ºC to -0.423 ºC. In 210 (12.5%) samples was higher than -0.515 ºC. The lowest freezing point (-0.532 ºC) was found in the samples collected in the first month after calving and highest (-0.522 ºC) in the samples of 12th month of lactation. The differences between the freezing point of milk after the first and the second calving (-0.530 ºC; P < 0.05) and those after the fifth calving (-0.523 ºC; P < 0.05) were also significant. The samples collected in month from January to April (-0.538 ºC to -0.532 ºC) were significantly lower in comparison to samples collected in May and June (-0.517 ºC and -0.519 ºC). The following statistically significant correlation coefficients between cows' properties, milk composition and the freezing point of milk were found: month of lactation r = 0.233 (P < 0.001); lactation number r = 0.196 (P < 0.001); age of cows (years) r = 0.231 (P < 0.001); month of the year r = 0.0253 (P < 0.001); milk yield per milking day r = -0.106 (P < 0.001); fat corrected milk content (FCM) per milking day r = -0.234 (P < 0.001); lactose % r = -0.530 (P < 0.001); fat % r = -0.351 (P < 0.001); protein % r = 0.058 (P < 0.05); urea mg/100 mL r = 0.091 (P < 0.001) and somatic cell count r = 0.154 (P < 0.001). The sum of effects (month of the year, lactation lenght and fat, protein and lactose content of milk) was found to account for about 70% variability of the total depression of milk freezing point (R2 = 0.698).http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=3972cows milkchemical compositionfreezing pointlactationseason |
| spellingShingle | Slavica Golc Teger Andrej Lavrenčić Aša Grahelj Freezing point of milk in a herd of high yielding dairy cows Mljekarstvo cows milk chemical composition freezing point lactation season |
| title | Freezing point of milk in a herd of high yielding dairy cows |
| title_full | Freezing point of milk in a herd of high yielding dairy cows |
| title_fullStr | Freezing point of milk in a herd of high yielding dairy cows |
| title_full_unstemmed | Freezing point of milk in a herd of high yielding dairy cows |
| title_short | Freezing point of milk in a herd of high yielding dairy cows |
| title_sort | freezing point of milk in a herd of high yielding dairy cows |
| topic | cows milk chemical composition freezing point lactation season |
| url | http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=3972 |
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