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The effects of milking frequency in early lactation on milk yield, mammary cell turnover, and secretory activity in grazing dairy cows

journal contribution
posted on 2023-05-03, 12:09 authored by Regan Murney, Kerst Stelwagen, Tom Wheeler, Jean Margerison, Kuljeet Singh
In dairy cows, short-term changes of milking frequency in early lactation have been shown to produce an immediate and a long-term effect on milk yield in stall-fed cows. The effect is controlled locally within mammary glands and could be a function of either secretory mammary epithelial cell number or activity. To resolve this and determine its applicability in other feed management systems, a unilateral milking frequency experiment was conducted with udder halves of 17 multiparous, pasture-fed dairy cows milked either 4 times (4×) or once a day (1×) for 14 d from 5 ± 2 d in milk. Mean half-udder milk yield during the treatment period was higher from the 4× compared with 1× udder halves and continued to be higher until 200 d in milk once returned to twice a day milking. Mammary biopsies were obtained on d 14 of treatment from both udder halves of 10 cows. Proliferation of mammary cells was higher in 4× udder halves compared with 1×, whereas no difference in apoptosis levels was detected. Abundance of αS1-casein, β-casein, α-lactalbumin, and β-lactoglobulin mRNA was higher in tissue samples from 4× udder halves compared with 1×, whereas lactoferrin mRNA abundance was lower in 4× udder halves. In summary, change in milking frequency during early lactation affects proliferation of mammary cells as well as expression of the major milk protein genes, which both contribute to the observed changes in milk yield during and after unilateral milking frequency treatment.

History

Rights statement

© American Dairy Science Association, 2015 .

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

Elsevier

Journal title

Journal of Dairy Science

Citation

Murney, R., Stelwagen, K., Wheeler, T. T., Margerison, J. K., & Singh, K. (2015). The effects of milking frequency in early lactation on milk yield, mammary cell turnover, and secretory activity in grazing dairy cows. Journal of Dairy Science, 98(1), 305-311. doi:10.3168/jds.2014-8745

Funder

Ministry of Business, Innovation & Employment

Contract number

A12391||C10X0702

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