Individual responses of dairy cows to a 24-hour milking interval

Abstract

Some dairy farmers opt to omit one milking, either incidentally or weekly, without changing other milking times. This practice entails an extended milking interval of 24h (24h-MI), which is associated with a decrease in milk yield. This decrease varies among cows and could be partly due to factors such as stage of lactation and milk yield level. The aim of this study was to describe the average and individual responses in terms of loss and carryover effects of a 24h-MI on milk yield. The influence of factors such as parity, stage of lactation, and milk yield potential were investigated, together with response repeatability. Our trial used 292 Holstein-Friesian cows, and consisted of 3 successive periods: 1 wk of twice-daily milking (TDM) as a control, one 24h-MI, and then 13d of TDM. The number of observations per cow ranged from 1 to 9, with no more than three 24h-MI per lactation. The 24h-MI reduced milk yield by 23% (7.8 kg on average) and milk lactose content by 2.6g/kg on the 24h-MI day. Milk fat and protein content, and somatic cell score increased by 3.0 g/kg, 0.5 g/kg, and 0.4 units, respectively. No significant carryover effect was found of a 24h-MI on milk yield or milk composition 2 wk after resumption of TDM. Milk yield loss and recovery varied widely (coefficient of variation 62%), and the relationship between milk loss and milk recovery showed substantial variation (residual standard deviation 2.1 kg/d). Cows with a greater milk potential level lost more milk yield but recovered more milk, with no influence on recovery:loss ratio. Cows in early lactation recovered the lost milk yield faster. Repeatability of the responses to a 24h-MI was 44% for milk yield loss (kg/d), 57% for relative milk yield loss (%), 33% for milk yield recovery (kg/d), and 0% for milk recovery:loss ratio (%), suggesting a genetically determined ability to limit loss when one milking is omitted. To conclude, a 24h-MI caused higher milk yield losses than reported in previous studies. Stage of lactation, estimated potential milk yield level, and parity explained the cows' response to the 24h-MI, but did not account for all the individual variability.

Genetic parameters of milk production traits in response to a short once-daily milking period in crossbred Holstein × Normande dairy cows

“…The greater decrease in milk lactose content on ODM-d1 could reflect the higher permeability of the mammary epithelium on that day. Here, milk protein content did not increase during ODM-d1, consistent with results reported by Auldist and Prosser (1998), who subjected 48 multiparous Friesian cows to 2 d of ODM, but in contrast to Charton et al (2016), who observed an increase of 0.5 unit of milk protein content with Holstein cows subjected to a single 24-h milking interval (724 observations and 289 cows). However, this steady milk protein content could conceal changes in protein proportions: Auldist and Prosser (1998) reported a reduction in casein: whey protein ratio with an increase in serum albumin and immunoglobulin G concentrations.…”

“…A single day of ODM might be a suitable candidate as an indicator trait in the second strategy; the most consistent and common pattern that has been reported when cows are switched to ODM is a reduction in milk yield occurring on the first day of ODM (Stelwagen et al, 2013). Charton et al (2016) recently showed that a 24-h milking interval was associated with a wide individual variability in responses, suggesting the existence of a genetic basis for this trait.…”

A new standard model for milk yield in dairy cows based on udder physiology at the milking-session level

“…Subsequent research was able to go further in describing system components and demonstrating how they interacted in dairy cows. For example, scientists focused on the dynamics of alveolar populations and of milk synthesis 38 – 42 ; the links between milk synthesis, udder compartments, and milking interval duration 43 – 52 ; and the consequences of udder-emptying problems for milk yield 53 – 66 .…”

Reducing milking frequency in early lactation improved the energy status but reduced milk yield during the whole lactation of primiparous Holstein cows consuming a total mixed ration and pasture

“…In fact, the reduction of 15% in cumulative milk yield in the whole lactation (43 wk) was explained by the lower milk yield during the treatment but also by a lower milk yield during the first 13 wk after the ending of the treatment. Decreasing milking frequency decreases the secretory ability of the mammary gland (Knight and Dewhurst, 1994;Grala et al, 2011), the storage capacity of the alveolar compartment (Dewhurst and Knight, 1993;Davis et al, 1998;Caja et al, 2004;Charton et al, 2016), and the hepatic metabolic rate (Grala et al, 2014). The results of the present study indicate that the physiological or metabolic processes do not have the potential to respond in a compensatory Figure 2.…”