Supplementation strategies for lactating dairy cows offered very high quality grass silages: Starch-based or fibre-based concentrates offered with or without straw
Date
2020-02-15
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
A three-period change-over design study using 24 mid-lactation multiparous Holstein-Friesian dairy cows, examined
supplementation strategies for a high quality grass silage (dry matter (DM), 418 g/kg; crude protein
(CP), 170 g/kg DM; metabolisable energy (ME), 12.1 MJ/kg DM). Four treatments, in a 2 × 2 factorial arrangement,
compared concentrate type (High-starch or High-fibre) and straw inclusion (Straw or No-straw).
Concentrates had a starch and neutral detergent fibre content of 373 and 258 g/kg DM, respectively (Highstarch),
and 237 and 339 g/kg DM, respectively (High-fibre). In the No-straw treatments, silage and concentrates
were offered as a total mixed ration in a 57:43 DM ratio. In the Straw treatments, chopped straw was added at
4% of total DM, replacing part of the silage component of the diet. Following this study, the effect of diet on
nutrient utilisation efficiency was examined using four cows/treatment. There were no interactions between
concentrate type and straw inclusion for any cow performance or digestibility parameters. Silage dry matter
intake (DMI) and total DMI were reduced with the High-fibre concentrate (P = 0.001 and P = 0.006, respectively)
and straw inclusion (P < 0.001 and P = 0.014, respectively). Neither concentrate type nor straw inclusion
had a significant effect on milk yield or milk fat content. The High-starch concentrate increased milk
protein content (P < 0.001), while straw inclusion decreased milk protein content (P = 0.036). Treatment had
no effect on cow body weight, condition score, faecal scores, digestibility coefficients or nitrogen and energy
utilisation efficiency. In conclusion, supplementing a high quality grass silage with a carefully formulated ‘high
starch’ concentrate improved DMI and milk protein content with no adverse effects on cow performance. Straw
inclusion in the diet had no beneficial effects on DMI, milk production or nutrient utilisation efficiency.
Description
Publication history: Accepted - 13 February 2020; Published online - 15 February 2020.
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Article
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Keywords
Dairy cows, High quality grass silage, Straw, Concentrate energy source, Fatty acids, Ration digestibility
Citation
Craig, A., Gordon, A. W., Stewart, S. and Ferris, C. P. (2020) ‘Supplementation strategies for lactating dairy cows offered very high quality grass silages: Starch-based or fibre-based concentrates offered with or without straw’, Livestock Science. Elsevier BV, 234, p. 103973. doi: 10.1016/j.livsci.2020.103973.