Effect of Postbiotic Supplementation on Nutrient Digestibility and Milk Yield during the Transition Period in Dairy Cows

Simple Summary Postbiotics are non-viable probiotic microorganisms, with or without their metabolites, that provide a health benefit to the host. They prevent the colonisation of pathogens by improving the gut environment for beneficial commensal bacteria. This effect reduces the incidence of digestive disorders in calves, which enhances animal growth and boosts the immune system and general health. The aim of this work was to evaluate the addition of postbiotics to dairy cow rations during the transition period on nutrient digestibility and milk productivity. The effects of two postbiotics from calving to two months of lactation were evaluated in twelve Friesian cows. The results suggest that postbiotic supplementation in late gestation and early lactation increases the voluntary intake of dry matter, with higher apparent total tract digestibility of nutrients. The inclusion of postbiotics in the dairy cow diet increases colostral immunoglobulin concentration and milk production with high fat and protein yields.Abstract The metabolites secreted by probiotics or released after their lysis are called postbiotics. They provide physiological benefits to the host, preventing the colonisation of pathogens by improving the intestinal environment for beneficial commensal bacteria, which reduces the incidence of digestive disorders and improves the immune system. The aim of this work was to evaluate the addition of postbiotics to dairy cow rations during the transition period on nutrient digestibility, composition, and milk yield. The effects of two postbiotics were evaluated in twelve Friesian cows from 30 days before calving to two months of lactation. The animals were randomly allocated to two treatment groups: control (CT) and supplemented with postbiotics (PC and PR). Feeding was ad libitum with 60/40 of forage/concentrate ratio on dry matter basis. Daily feed intake and milk production were recorded individually throughout the study. Two digestibility balances were performed, one before parturition and one after parturition. Colostrum was sampled at first milking and milk was sampled weekly. Data were analysed using a mixed mode in R software 4.4.1. The results suggest that postbiotic supplementation in late gestation and early lactation increase the voluntary intake of dry matter, especially in the PR treatment, with higher apparent total tract digestibility of dry matter, organic matter and neutral detergent fibre. Both treatments including postbiotics induced an increase in colostral immunoglobulin concentration. Milk production of cows receiving the PC treatment was the highest, with high fat and protein yields and a higher persistence of the production curve throughout the lactation.