An examination of two concentrate allocation strategies which are based on the early lactation milk yield of autumn calving Holstein Friesian cows

Abstract

The objective of this experiment was to compare the effects of two concentrate feeding strategies offered with a grass silage and maize silage diet on the dry matter (DM) intake, milk production (MP) and estimated energy balance of autumn calved dairy cows. Over a 2-year period, 180 autumn calving Holstein Friesian cows were examined. Within year, cows were blocked into three MP sub-groups (n = 9) (high (HMP), medium (MMP) and low (LMP)) based on the average MP data from weeks 3 and 4 of lactation. Within a block cows were randomly assigned to one of two treatments (n = 54), flat rate (FR) concentrate feeding or feed to yield (FY) based on MP sub-group. Cows on the FR treatment were offered a fixed rate of concentrate (5.5 kg DM/cow per day) irrespective of MP sub-group. In the FY treatment HMP, MMP and LMP cows were allocated 7.3, 5.5 and 3.7 kg DM of concentrate, respectively. The mean concentrate offered to the FR and FY treatments was the same. On the FR treatment there was no significant difference in total dry matter intake (TDMI, 17.3 kg) between MP sub-groups. In the FY treatment, however, the TDMI of HMP-FY was 2.2 kg greater than MMP-FY, and 4.5 kg greater than LMP-FY (15.2 kg DM). The milk yield of LMP-FR was 3.5 kg less than the mean of the HMP-FR and MMP-FR treatments (24.5 kg). The milk yield of the HMP-FY treatment was 3.6 and 7.9 kg greater than the MMP-FY and LMP-FY treatments, respectively. The difference in MP between the HMP sub-groups was 2.6 kg, which translates to a response of 1.4 kg of milk per additional 1 kg of concentrate offered. There was no significant difference in MP between the two LMP sub-groups; however, MP increased 0.8 kg per additional 1 kg of concentrate offered between cows on the LMP-FR and LMP-FY treatments. The estimated energy balance was positive for cows on the LMP-FR treatment, but negative for cows on the other treatments. The experiment highlights the variation within a herd in MP response to concentrate, as cows with a lower MP potential are less responsive to additional energy input than cows with a greater MP potential. Cows with a greater MP capacity did not substitute additional concentrate for the basal forage, which indicates an additional demand for energy based on ability of individual cows to produce milk.

Effects of an individual cow concentrate strategy on production and behavior

“…In comparison, the results of previous studies had an almost similar mean concentrate intake for the compared strategies (Lawrence et al, 2016;Little et al, 2016;Purcell et al, 2016). In general, previous studies on individual cow concentrate strategies resulted in the same level of total feed intake as the control strategy for both loose-housed cows (Lawrence et al, 2016;Little et al, 2016;Purcell et al, 2016) and cows on pasture (Garcia et al, 2007;Dale et al, 2016b). These results across studies and strategies imply that dairy cows have a high level of robustness to changes in concentrate strategy because they seem to adapt by adjusting their intake according to their energy requirements.…”

“…However, if allocated concentrate allowance had reached the intended allowance, the variation between cows in percentage of allocated concentrate should have been lower for individually fed cows than control cows. In comparison, the results of previous studies had an almost similar mean concentrate intake for the compared strategies (Lawrence et al, 2016;Little et al, 2016;Purcell et al, 2016). In general, previous studies on individual cow concentrate strategies resulted in the same level of total feed intake as the control strategy for both loose-housed cows (Lawrence et al, 2016;Little et al, 2016;Purcell et al, 2016) and cows on pasture (Garcia et al, 2007;Dale et al, 2016b).…”

“…Previous studies on the effects of an individual cow concentrate strategy during lactation have been conducted on cows in milking systems other than AMS (Maltz et al, 2013;Lawrence et al, 2016;Little et al, 2016); however, in an AMS, the effects of a concentrate strategy on the daily visiting frequency and milkings are important. André et al (2007André et al ( , 2010 studied the short-term responses of cows to a dynamic concentrate strategy in an AMS.…”

The Impact on Cow Performance and Feed Efficiency When Individual Cow Milk Composition and Energy Intake Are Accounted for When Allocating Concentrates

“…3 Precision 2; concentrates offered on a FTY basis, adjusted on the basis of individual cow milk yields, milk composition, and dry matter intake. 4 Standard error of the differences of the mean. ab Within a row, means without a common superscript are significantly different (p < 0.05) There were no significant differences between treatments for milk yield (Figure 2) or ECM yield (p > 0.05; Table 3).…”

“…Additional concentrates are then offered to individual cows on a FTY basis to support milk production above the yield that the forage/basal ration is assumed to support. However, while FTY systems are widely adopted, the literature provides little evidence that either performance or efficiency is improved when FTY systems are compared to 'flat-rate' feeding systems [3][4][5][6]. However, the majority of these studies targeted equal concentrate inputs within both feeding approaches, and this may have constrained the ability of cows to respond.…”