Nutrient Composition and Feed Hygiene of Alfalfa, Comparison of Feed Intake and Selected Metabolic Parameters in Horses Fed Alfalfa Haylage, Alfalfa Hay or Meadow Hay

Simple Summary Increased periods of drought and the resulting shortage of forage necessitate the development of new strategies to find forage alternatives for equine nutrition. Alfalfa (Medicago sativa) is a heat-tolerant and high-yielding plant that provides high levels of protein and minerals, such as calcium (Ca) and magnesium (Mg). Alfalfa hay (AH) is an adequate forage alternative to meadow hay that seems to positively impact the fermentation profile in the large intestine in horses. However, little is known about feeding wrapped alfalfa as an alternative forage source in equine diets. Furthermore, its preservation in the form of haylage minimises leaf losses compared with that of alfalfa hay. The aim of this study was to examine the nutrient composition and feed hygiene of alfalfa as well as investigate the feed intake, blood, urine and faecal parameters of horses fed alfalfa haylage (AS) compared with AH and meadow hay (MH). Voluntary feed intake, nutrient values and faecal quality support AS as a suitable forage source in equids. In addition, the intake of wrapped forage provides a dust-free feed, which may be beneficial for horses suffering from equine asthma. Furthermore, its preservation in the form of haylage minimises leaf losses compared with that of alfalfa hay.Abstract The aim of this study was to examine the nutrient composition and feed hygiene of alfalfa as well as investigate the feed intake, blood, urine and faecal parameters of horses fed alfalfa haylage (AS) compared with alfalfa hay (AH) and meadow hay (MH). A total of 11 geldings were fed ad libitum (2.1% dry matter (DM) of body weight (BW)) with alfalfa haylage, alfalfa hay and meadow hay (MH) in a Latin square design. On days 0 and 21 of the feeding period, blood samples were analysed for kidney and liver parameters. Faecal samples were analysed for pH, DM and short-chain fatty acids (SCFAs). Spontaneous urine was collected during the feeding period to analyse selected parameters. Forage was analysed in terms of feed hygiene and crude nutrients. In several feed samples of AS, AH and MH, the microbial reference ranges were exceeded for product-typical and spoilage-indicating bacteria and fungi. Crude nutrient analyses revealed a median crude protein content of 139 (138/142) g/kg DM for AS, which was similar to that in AH (127-135 g/kg DM) and substantially higher than in MH (79.1-87.7 g/kg DM). The calcium level in AS (11.3 g/kg DM) was significantly higher than that in MH (4.00-4.95 g/kg DM) but not compared with that in AH (9.80-10.4 g/kg DM). All blood parameters were within the reference ranges. Fractional excretion (FE)Ca for AS-fed horses ranged from 8.13 to 22.0%; the FECa for AH-fed horses ranged from 6.48 to 24.8%; the FECa for MH-fed horses ranged from 6.69 to 53.2%. No significant differences were found in faecal pH or SCFA content in AS-fed horses compared with AH-fed and MH-fed horses. We concluded that alfalfa haylage provides an alternative forage for equine nutrition.