Abstract
Milk production loss was studied in relation to increased somatic cell count (SCC). Available data were weekly test-day milk yields and SCC (in 1,000 cells/ml), and mastitis incidences. In total, 18,131 records from 274 cows were used. Production loss was determined for test-day kg milk, kg protein, and kg energy-corrected milk. Least-squares analysis of variance was used to estimate the direct effect of Log10(SCC) on production. The recorded measures of production were first corrected for fixed effects, with adjustment factors estimated from a healthy data-set.
The average daily milk yield was 19.7 kg/day in first lactation and 22.0 in later lactations. The geometric mean of SCC was 63.1 in first lactation and 107.2 in later lactations. The incidence of clinical mastitis treated by a veterinarian was 19.8% of the lactations-at-risk. Linear relationships were found between the production parameters and Log10(SCC). Quadratic and cubic effects were evaluated, but were found to contribute little to the overall fit of the models. The individual milk yield loss was 1.29 kg/day for each unit increase in Log10(SCC) for cows in first lactation. Milk yield decreased by 2.04 kg/day per unit Log10(SCC) for older cows. Corresponding values for protein yield were 0.042 and 0.067 kg/day for first and later lactations, respectively.
Keywords: dairy cows, mastitis, milk loss
Sammanfattning
Sambandet mellan avkastning och cellhalt studerades på ett material omfattande 18.131 veckovisa observationer från 274 kor på en försöksstation. Avkastningsförluster skattades med minsta-kvadrat metodik för kg mjölk, kg protein och kg energikorrigerad mjölk. I syfte art undvika skattningsfel korrigerades avkastningsuppgifterna, före analys, till en nivå som kunde förväntas för uppgifter som inte påverkats av mastit.
I första laktationen var den genomsnittliga avkastningen 19,7 kg/dag, det geometriska medelvärdet för cellhalt 63,1 1000-tal celler/ml och incidensen klinisk mastit 14,5 fall per 100 risk-laktationer. Motsvarande siffror för äldre kor var 22,0 kg/dag, 107,2 1000-tal celler/ml respektive 22,7 fall per 100 risk-laktationer.
Resultaten visade på ett linjärt samband mellan avkastning och log10(cellhalt). Kvadratiska och kubiska termer undersöktes, men de bidrog mycket lite till modellens forklaringsgrad. Den uppskattade förlusten per enhets ökning i log10(cellhalt) var 1,29 kg mjölk/dag i första laktation och 2,04 kg/dag i senare laktationer. Motsvarande siffror för protein-avkastningen var 0,042 kg/dag respektive 0,067 kg/dag.
Full Text
The Full Text of this article is available as a PDF (1.2 MB).
References
- Bartlett PC, Miller GY, Anderson CR, Kirk JH. Milk production and somatic cell count in Michigan dairy herds. J. Dairy Sci. 1990;73:2794–2800. doi: 10.3168/jds.S0022-0302(90)78966-7. [DOI] [PubMed] [Google Scholar]
- Dabdoub SAM, Shook GE: Phenotypic relationships among milk yield, somatic cell count and clinical mastitis. J. Dairy Sci. 1984, 67 (suppl. 1), 163– 164.
- Deluyker HA, Gay JM, Weaver LD. Interrelationships of somatic cell count, mastitis, and milk yield in a low somatic cell count herd. J. Dairy Sci. 1993;76:3445–3452. doi: 10.3168/jds.S0022-0302(93)77683-3. [DOI] [PubMed] [Google Scholar]
- Dentine MR, McDanielB: Evidence for non-linearity in the relationship between milk and fat yields and the logarithm of the geometric mean of monthly somatic cell counts. J. Dairy Sci. 1983, 66 (suppl. 1), 112.
- Dohoo IR, Meek AH, Martin SW. Somatic cell counts in bovine milk: Relationships to production and clinical episodes of mastitis. Can. J. Comp. Med. 1983;48:130–135. [PMC free article] [PubMed] [Google Scholar]
- Dohoo IR, Morris RS. Somatic cell count patterns in Prince Edward Island dairy herds. Prev. Vet. Med. 1993;15:53–65. doi: 10.1016/0167-5877(93)90075-5. [DOI] [Google Scholar]
- Emanuelson U, Funke H. Effect of milk yield on relationship between bulk milk somatic cell count and prevalence of mastitis. J. Dairy Sci. 1991;74:2479–2483. doi: 10.3168/jds.S0022-0302(91)78424-5. [DOI] [PubMed] [Google Scholar]
- Erb HN. Interrelationships among production and clinical disease in dairy cattle: A review. Can. Vet. J. 1987;28:326–329. [PMC free article] [PubMed] [Google Scholar]
- Firat MZ. An investigation into the effects of clinical mastitis on milk yield in dairy cows. Livest. Prod. Sci. 1993;35:311–321. doi: 10.1016/0301-6226(93)90048-M. [DOI] [Google Scholar]
- Heuven HCM: Diagnostic and genetic analysis of mastitis field data. PhD-thesis, Dept. of Dairy Science, University of Wisconsin, Madison, 1987, 1–145.
- Holmberg O, Isaksson A: Nomenklaturen vid bovina mastiter. (Terminology for bovine mastitis). Sv. Vet. Tidn. 1993, 22, 808–811. (in Swedish).
- Houben EHP, Dijkhuizen AA, Van Arendonk JAM, Huirne RBM. Short- and long-term production losses and Repeatability of clinical mastitis in dairy cattle. J. Dairy Sci. 1993;76:2561–2578. doi: 10.3168/jds.S0022-0302(93)77591-8. [DOI] [PubMed] [Google Scholar]
- Jones GM, Pearson RE, Clabaugh GA, Heald CW: Relationships between somatic cell counts and milk production. J. Dairy Sci. 1984, 67, 1823– 1831. [DOI] [PubMed]
- Lucey S, Rowlands GJ. The association between clinical mastitis and milk yield in dairy cows. Anim. Prod. 1984;39:165–175. [Google Scholar]
- Lucey S, Rowlands GJ, Russell AM. Short-term associations between disease and milk yield of dairy cows. J. Dairy Res. 1986;53:7–15. doi: 10.1017/S0022029900024602. [DOI] [PubMed] [Google Scholar]
- Miller RH, Emanuelson U, Persson E, Brolund L, Philipsson J, Funke H. Relationships of milk somatic cell counts to daily milk yield and composition. Acta agric. scand. 1983;33:209–223. doi: 10.1080/00015128309439885. [DOI] [Google Scholar]
- Nielen M, Schukken YH, De Van Broek J, Brand A, Deluyker HA, Maatje K. Relations between online electrical conductivity and daily milk production on a low somatic cell count farm. J. Dairy Sci. 1993;76:2589–2596. doi: 10.3168/jds.S0022-0302(93)77593-1. [DOI] [PubMed] [Google Scholar]
- Raubertas RF, Shook GE. Relationship between lactation measures of somatic cell concentration an milk yield. J. Dairy Sci. 1982;65:419–425. doi: 10.3168/jds.S0022-0302(82)82207-8. [DOI] [Google Scholar]
- Salsberg E, Meek AH, Martin SW. Somatic cell counts: Associated factors and relationship to production. Can. J. Comp. Med. 1984;48:251–257. [PMC free article] [PubMed] [Google Scholar]
- SAS Institute Inc: SAS/STAT User’s Guide, Version 6, fourth edition, Volume 1. Cary, 1989.
- Schepers JA, Dijkhuizen AA. The economics of mastitis and mastitis control in dairy cattle; a critical analysis of estimates published since 1970. Prev. Vet. Med. 1991;10:213–224. doi: 10.1016/0167-5877(91)90005-M. [DOI] [Google Scholar]
- Sjaunja L-O: Methods for calculations of the energy content of milk. 24th Session of the International Committee for Recording the Productivity of Milk animals (ICRPMA), Södertälje. 1984.
- Solbu H: Virkning av sjukdom pa melkeproduksjonen. (Effect of disease on milk production). Meieriposten, 1988, 77, 178–179. (in Norwegian)
- Tyler JW, Thurmond MC, Lasslo L. Relationship between test-day measures of somatic cell count and milk production in California dairy cows. Can. J. Vet. Res. 1989;53:182–187. [PMC free article] [PubMed] [Google Scholar]