Lactation - Milking Frequency

http://ansci.illinois.edu/static/ansc438/Lactation/milkingfrequency.html[7/26/2016 10:34:44 AM]

ANSC 438 Home / Beginning / Milk Composition / Mammary Structure

Mammary Development / Mother & Neonate / Lactation / Mastitis

Lactation

Resource Library

Milking Frequency

Milking

Frequency

Frequency of Nursing or Milking

The frequency at which milk is removed from the mammary gland by the suckling offspring varies

substantially among species. For example:

Nursing frequency may

be: Species

continuous kangaroo (joey)

or at intervals of:

.5 hr whale, dolphin

1 hr pig

4-6 hr cow

1X/day rabbit

1X/2 days tree shrew

1X/week Northern fur seal

Milking Frequency in Dairy Cattle

In the case of dairy cattle,

management considerations

determine how often cows are

milked each day. In most dairy cattle

management schemes, cows are

milked twice daily or three times

daily.

In the case of robotic milking systems (mostly in Europe, but a few

currently are in use in North America) where the cows are free to

enter the robotic milker as often as they want, typically cows will
Lactation - Milking Frequency

http://ansci.illinois.edu/static/ansc438/Lactation/milkingfrequency.html[7/26/2016 10:34:44 AM]

enter 4 or less times per day. Little additional benefit is attained if

they are milked more than 4 times per day.

This is one model of a robotic

milking machine that has not

been fully set-up. Cows would

enter the gates shown on this

side of the machine.

Cows are milked by the machine

shown at the bottom of the

image. Controls for the milking

machine are on this side of the

robotic machine.

Below are summarized some of the original observations on milking frequency in dairy cattle and how

those frequencies affect milk yeild.

A. 3 times/day vs. 2 times/day milking. In dairy cattle, milking 3X/day results in increased milk yield,

although the observed increase is variable. Generally 3X/day milking increases milk production by up

to 25%. But, ~2/3 of this increase is due to better feeding and management and ~1/3 is due to

decreased udder pressure. 3X/day milking must be accompanied by a compensatory feeding

program; if not, then yield from the continued 3X/d milking will decline back to that from 2X/d. Three

times per day milking is more beneficial in late lactation, for example during the first 4 mos. of lactation

3X/day milking increases yield 7-12% over 2X/d. In contrast, during later lactation 3X/day milking

increases yield 16-90% over 2X/d. Both first lactation and older cows show increased yield in 3X/day

vs. 2X/day milking.

Mammary DNA , RNA and activities of key mammary enzymes are increased in 3x/day milking, vs.

2x/day milking. (see Wilde et al., 1987, J. Anim. Sci. 64:533.)

In switching from 2X/day to 3X/day milking, the cow's response is thought to occur in stages with each

stage reflecting a different mechanism (see Table and discussion below).

Sequential Response to Thrice-Daily Milking

Stage Time Mechanism Response

1

Immediate

(hours to

days)

removal of chemical

feedback inhibitor

increased milk

secretion

2

Short Term 

(days to

weeks)

stimulation of cell

differentiation

increased milk

secretion

3

Long Term 

(weeks to

months)

stimulation of cell

proliferation

increased milk

secretion

Evidence for stage 1: 3X/day milking of one gland produces a unilateral response (see Henderson et

al., 1983, Quart. J. Exper. Physiol. 68:645) due to milk removal, not due to decreased physical

distention (see Henderson and Peaker, 1984, J. Physiology 351:39).
Lactation - Milking Frequency

http://ansci.illinois.edu/static/ansc438/Lactation/milkingfrequency.html[7/26/2016 10:34:44 AM]

Evidence for stage 2: There is greater activity of several key enzymes occurs in 3X/day milking (see

Wilde et al., 1987, J. Anim. Sci. 64:533).

Evidence for stage 3: There is greater number of cells in the 3X/day milked glands (see Wilde et al.,

1987, J. Anim. Sci. 64:533).

Milking 3x/day requires 50% more labor than 2x/day milking. For an economic evaluation of 3X/day

vs. 2X/day milking see Culotta and Schmidt, 1988, J. Dairy Sci. 71:1960. The incidence of mastitis

and the reproductive performance are not altered by 3X/d milking.

For other references on 3X/day milking vs. 2X/day milking see Pearson et al., 1979, J. Dairy Sci.

62:1941; Waterman et al., 1983, J. Dairy Sci. 66:253; DePeters et al., 1985, J. Dairy Sci. 68:123;

Amos et al., 1985, J. Dairy Sci. 68:732; Gisi et al., 1986, J. Dairy Sci. 69:863; Allen et al., 1986, J.

Dairy Sci. 69:1441; Wilde et al., 1987, J. Anim. Sci. 64:533.

B. Milking udder halves. Milking one udder half 3X/day gives 16-32% more milk than the udder half

milked only 2X/day, even though the halves are exposed to the same systemic stimulation.

Also, milking 2 quarters of cows 4X/day resulted in ~10% increase in milk yield compared to the

quarters milked 2X/day (see Hillerton et al., 1990 J. Dairy Res. 57:285). NOTE: In this study, the right

rear and left fore quarters were milked 4X/day and the right fore and left rear quarters were milked

2X/day. Remember that the blood flow to one side of the udder serves both front and rear quarters but

there is little crossover from left to right. So, this study's results also suggest that the effects are local

(within an individual quarter), because the blood flow and systemic hormone concentrations would be

the same to both quarters on one side.

C. 4x/day milking. Milking 4X/day results in 5-10% more yield than 3x/day. But is it economical where

labor costs are doubled caompared with 2X/day?

D. BST administration to goats milked 3X/day. This resulted in greater milk yield than either in goats

receiving BST and milked 2X/day or in goats receiving no BST and milked 3X/day. So, the effects of

3X/day milking and BST apparently are additive.

E. Massaging udders between milkings. This can cause an increase of 1-1.5% in milk yield, although

this is probably not statistically significant.

F. Milking less than 2X/day. Milking 3X in 2 days (skipping 1 out of every 4 milkings) resulted in

decreased milk yields of 18% when started in week 4 of lactation and a decrease of 11% when started

in week 20 (see Eldridge and Clark, 1978, J. Dairy Res. 45:509).

1X/day milking during late lactation results in 35% less milk yield than 2X/day during that period

and 12% less milk for the entire lactation. The average length of lactation was reduced by 12

days.

1X/day milking for a complete lactation reduces milk yield by 50% in first calf heifers and

reduces milk yield by 40% in older cows.

Milking 13X/week vs 14X/week (skipping 1 milking per week; that's 7% fewer milkings per

week) reduces milk yield by 5-11% (see Radcliffe et al., 1973, J. Dairy Res. 40:247).

Eliminating 2 consecutive milkings/week reduces milk yield by 14% (see Radcliffe et al., 1973,

J. Dairy Res. 40:247).

So, while milking frequency can have a significant impact on milk yield in cattle when viewed from the

producer's viewpoint, the fact remains that the gland is highly resilient and continues lactating

successfully with biologically minor decreases in milk yield even under conditions radically different

from modern dairy management practices.

Lactation

Lactation Resources
Lactation - Milking Frequency

http://ansci.illinois.edu/static/ansc438/Lactation/milkingfrequency.html[7/26/2016 10:34:44 AM]