title: Effect of the type of silage on milk yield, intake and rumen metabolism of dairy cows grazing swards with low herbage mass.
abstract: The aim of this study was to evaluate the effect of herbage allowance (HA) and type of silage supplemented (TS) on milk yield, dry matter intake (DMI) and metabolism of dairy cows in early lactation. Thirty-six Holstein-Friesian dairy cows were allocated to four treatments derived from an arrangement of two HA (LHA = 17 or HHA = 25 kg of DM/cow/day) and two TS (grass (GS) or maize (MS)). Herbage allowance had no effect on DMI or milk yield. Rumen pH and NH3 -N concentration were not affected by HA. The efficiency of microbial protein synthesis in the rumen (microbial protein (MP)) was affected by HA with 21.5 and 23.9 g microbial nitrogen per kg ruminal digestible organic matter for LHA and HHA, respectively (P < 0.05). Supplementation with MS showed higher values of milk yield by 2.4 kg/cow/day (P < 0.001), milk protein content by 0.10 % (P < 0.023) and herbage DMI by 2.2 kg/cow/day, and showed lower values for milk urea compared to GS (P < 0.001). The former results suggest that TS had a greater effect on milk yield, total feed intake and energy intake than increase in herbage allowance; however, increase in HA had greater effects on MP than TS.
authors.affiliation: Institute of Animal Science, Faculty of Veterinary Sciences.
authors.forename: Miguel
authors.identifier: http://orcid.org/0000-0002-1419-151X
authors.initials: M
authors.lastname: Ruiz-Albarrán
authors.affiliation: Institute of Animal Production Faculty of Agricultural Sciences.
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Balocchi
authors.affiliation: Institute of Veterinary Clinical Science- Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: Mirela
authors.initials: M
authors.lastname: Noro
authors.affiliation: Institute of Veterinary Clinical Science- Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Wittwer
authors.affiliation: Institute of Animal Science, Faculty of Veterinary Sciences.
authors.forename: Rubén G
authors.initials: RG
authors.lastname: Pulido
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000818:Animals; D002417:Cattle / Q000378:metabolism* / Q000502:physiology*; D003612:Dairying; D004032:Diet / Q000662:veterinary*; D004435:Eating / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology; D005260:Female; D060434:Herbivory / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D007774:Lactation / Q000502:physiology*; D008892:Milk; D009584:Nitrogen / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D012417:Rumen / Q000378:metabolism* / Q000382:microbiology; D012820:Silage
chemical_list: D011506:Proteins; D000641:Ammonia; D009584:Nitrogen
keywords: dairy cow; herbage allowance; low herbage mass; milk yield; type of silage