Once-daily milking during a feed deficit decreases milk production but improves energy status in early lactating grazing dairy cows

Abstract

The objective of this study was to investigate the effect of milking frequency (MF) at 2 feeding levels (FL) on milk production, body condition score, and metabolic indicators of energy status in grazing dairy cows during early lactation. Multiparous Holstein-Friesian and Holstein-Friesian × Jersey cows (n=120) grazed pasture and were milked twice daily (2×) from calving until 34 ± 6 d in milk (mean ± standard deviation). Cows were then allocated to 1 of 4 treatments in a 2 × 2 factorial arrangement. Treatments consisted of 2 FL: adequately fed [AF; 14.3 kg dry matter intake (DMI)/cow per d] or underfed (UF; 8.3 kg of DMI/cow per d) and 2 MF: 2× or once daily (1×). Treatments were imposed for 3 wk. After the treatment period, all cows were offered a generous pasture allowance (grazing residuals >1,600 kg of dry matter/ha) and milked 2×. During the 3-wk treatment period, we observed an interaction between FL and MF for energy-corrected milk (ECM), such that the decrease due to 1× milking was greater in AF than in UF cows (20 and 14% decrease, respectively). No interactions were found posttreatment. Cows previously UF produced 7% less ECM than AF cows during wk 4 to 12; however, no subsequent effect was observed of the previous underfeeding. Cows previously milked 1× produced 5% less ECM during wk 4 to 12, and differences remained during wk 13 to 23. During the 3-wk treatment period, UF cows lost 0.2 body condition score units (1-10 scale) and this was not affected by 1× milking. During the treatment period, UF cows had lower plasma glucose, insulin, and insulin-like growth factor I, and greater nonesterified fatty acids and β-hydroxybutyrate concentrations than AF cows. Cows milked 1× had greater plasma glucose, insulin, and insulin-like growth factor I, and lower nonesterified fatty acids and β-hydroxybutyrate concentrations compared with cows milked 2×. In conclusion, energy status was improved by 1× milking; however, when UF cows were milked 1×, milk production was reduced by more than underfeeding alone. The immediate and residual responses to 1× milking need to be considered when using this management strategy during a feed deficit.

Lactation traits associated with short- and long-term once-daily milking performance in New Zealand crossbred dairy cattle

“…Negative, additive effects of ODM and under-nutrition on milk production have been reported, although the data indicate that when intake is restricted, cows sometimes have a smaller percentage loss in milk production following transition from TDM to ODM (Auldist and Prosser, 1998;Kay et al, 2013). In the current study, there was a markedly smaller percentage loss in production (12.4%) in cohort 1 in late lactation during ST-ODM2 relative to the other ST-ODM challenges.…”

Expression of key lipid metabolism genes in adipose tissue is not altered by once-daily milking during a feed restriction of grazing dairy cows

“…The experimental design, grazing management, milk production, BW, BCS, and plasma hormone and metabolite measurements were as described previously (Kay et al, 2013). Briefly, multiparous Holstein-Friesian and Holstein-Friesian × Jersey dairy cows (n = 120) were grazed on pasture as 1 herd (to target postgrazing residuals of >1,600 kg of DM/ha), and milked 2× for the first 34 ± 6 DIM (mean ± SD).…”

“…Reducing milking frequency (MF) from twice-(2×) to once-daily (1×) is one strategy proposed to manage the energy balance of dairy cows (Auldist and Prosser, 1998;Kay et al, 2013), as 1× milking reduces milk production (Davis et al, 1999) and, consequently, decreases energy demands by the mammary gland. Cows milked 1× have reduced BCS and BW loss, and improved energy balance compared with cows milked 2× (Rémond et al, 2002;Guinard-Flament et al, 2007).…”

“…Cows milked 1× have reduced BCS and BW loss, and improved energy balance compared with cows milked 2× (Rémond et al, 2002;Guinard-Flament et al, 2007). Milking cows 1× instead of 2× during a feed restriction limits both the increase in plasma NEFA concentrations and the decrease in plasma glucose and insulin concentrations (Guinard-Flament et al, 2007;Kay et al, 2013). However, Kay et al, (2013) reported that the improvements in energy status due to 1× milking were not sufficient to prevent BCS loss during 3 wk of underfeeding of grazing dairy cows during early lactation.…”

“…The different effects of nutrition and milk production on lipid metabolism, combined with the lower plasma NEFA concentrations in cows milked 1× relative to 2× (Kay et al, 2013), led to the hypothesis that milking cows 1× during a feed restriction would minimize lipolysis and enhance lipogenesis in adipose tissue. Therefore, the objective of this experiment was to measure the expression of genes involved in lipid metabolism in adipose tissue, during and after a feed restriction in cows milked 1× or 2×, to determine the effect of reduced MF during an energy deficit.…”