Impact of humic acid as an organic additive on ruminal fermentation constituents, blood parameters and milk production in goats and their kids growth rate

Abstract

Impact of humic acid (HA) on ruminal fermentation characteristics, blood parameters and milk yield in goats and growth rate of their kids was determined. Twenty late pregnant Barki goats (45.4 ± 1.5 kg body weight) were allocated into two treatments (10 goats per treatment), housed individually in closed pens (one goat per pen) and fed a total mixed ration (TMR) twice a day. The TMR was composed of 400 g roughage and 600 g concentrate mixture. Goats were fed either TMR without HA (control diet, CTL) or orally drenched with HA at a dose of 2 g · d–1 per goat (HA diet) for 14 days prepartum and 56 days postpartum. The results revealed that HA increased ruminal pH, acetate and propionate proportions, while ammonia concentration and protozoa number were decreased. Administration of HA reduced daily dry matter intake and total faecal egg count. Animals treated with HA were characterised with increased blood total protein, globulin and glucose levels, while reduced blood urea nitrogen, cholesterol, non-esterified free fatty acids and β-hydroxybutyrate concentrations were stated. Milk, fat, lactose and protein yields increased, while milk urea nitrogen and somatic cell count decreased with HA treatment. Milk fat and protein contents were increased for goats treated with HA. Kids reared by goats treated with HA had increased body weight and 31% greater daily weight gain than CTL ones. So, HA could be efficiently used as a promising organic additive to modulate ruminal fermentation pattern. Administration of HA improved milk yield and its quality in goats, and also growth rate of their kids with no adverse effects on animal health.