Evaluation of a high-fibre total mixed ration as a dry cow feeding strategy for spring-calving Holstein Friesian dairy cows

Abstract

This study compared the milk production, body condition score (BCS), bodyweight (BW), plasma analyte profiles and reproductive performance, of spring-calving Holstein Friesian cows offered either grass silage or a wheat straw-based total mixed ration (TMR) during the dry period. Fifty-eight multiparous cows were paired according to parity (2, 3 or > 3), expected calving date and BCS, and randomly assigned to one of two experimental treatments: (i) a high-fibre total mixed ration (HF-TMR) containing 400 g/kg wheat straw on a DM basis, or (ii) a control diet of perennial ryegrass silage (GS). Diets were offered ad libitum for the duration of the dry period (overall mean 88 ± 17d). Post-calving, cows were offered 15 kg DM of perennial ryegrass ( Lolium perenne), supplemented with 3 kg DM of concentrate daily. At calving, BCS (3.48 and 3.11, P = 0.04) and BW (709 and 651 kg, P = 0.01) were greater for treatment GS than treatment HF-TMR. There was no difference between treatments ( P > 0.05) in the degree of BCS or BW change during weeks 1–8 post-partum. Solids-corrected milk yield (30.7 and 28.5 kg/d, P = 0.03), and fat yield (1.38 and 1.25 kg/d, P = 0.02) were greater for treatment GS than for treatment HF-TMR for weeks 1–8 post-partum. Plasma profiles were similar for most metabolites for both treatments from week one pre-partum to week four post-partum. β-hydroxybutyrate (BHB) was greater for treatment GS than for treatment HF-TMR (0.31 and 0.12 mmol/L, P = 0.02) as was glutamate-dehydrogenase (GLDH) (2.63 and 2.33 iu/L, P = 0.03). No difference ( P > 0.05) was observed for measures of subsequent fertility. In conclusion, this study found that offering a HF-TMR during the dry period did not confer any subsequent advantage relative to moderate quality grass silage, where cows were not over conditioned in the dry period.