Search

This study aimed to examine and compare the effectiveness of a novel spray-dried inoculant and a commercial freeze-dried additive on the fermentation quality, aerobic stability and bacterial population of vetch-oat silage. An entirely random design used a 3 × 4 factorial arrangement of treatments, with and without lactic acid bacteria (LAB) inoculants and four fermentation periods. Physicochemical parameters, microbiological counts and 16S rRNA gene sequencing analysis on Nanopore MinION were conducted to characterize the ensiling process. Both LAB inoculants increased dry matter, crude protein, lactic, acetic and propionic acid contents, while reducing pH, neutral detergent fibre, ammonia nitrogen/total nitrogen and ethanol concentrations compared to the control group. Overall, the native inoculant decreased the cell load of coliforms, yeasts and moulds. In addition, bio-inoculants enhanced the aerobic stability of vetch-oat intercrops. After ensiling, bacterial alpha diversity decreased noticeably; inoculation reduced the number of observed operational taxonomic units and the Shannon and Simpson indices. Notably, the relative abundance of Lactobacillus in the control group was lower than in treated silages, while the relative values of Staphylococcus increased sharply in the uninoculated group. In conclusion, the native strains showed promise for usage as a bio-inoculant in the ensiling of vetch-oat at a mixture rate of 1:1, producing an immediate impact as well as a favourable effect on the post-opening phase. This represents the first report on 16S rRNA gene-based nanopore metagenomics applied to the bacterial analysis of vetch-oat silage, providing a microbiological insight where native and commercial strains dominate the natural epiphytic community. [ABSTRACT FROM AUTHOR]

In Argentine grazing systems, additional supply of energy and protein is needed to balance the diet during periods of pasture shortage in winter. Three protein meal sources were evaluated, in terms of milk yield and composition, for grazing dairy cows receiving a supplementary PMR. Thirty three multiparous cows, averaging 75 ± 15 DIM, and over 7000 L/cow in previous lactations, were randomly assigned to 3 treatments: SM= soybean meal, L-SuM= sunflower meal-low-protein and CM= canola meal, in a continuous split-plot design with covariance analysis. The diets were isoenergetic (1.82 Mcal NEL) and isonitrogenous (17% CP), and were formulated (DM basis) with 17 % pasture and 83% of a PMR containing corn silage, alfalfa hay, corn grain, minerals and vitamins premix and the corresponding protein meal. The CP concentrations were 28, 35 and 41% for L-SuM, CM and SM, and represented 25, 20 and 15% total diet DM, respectively. Table 1 shows milk yield and composition for all treatments. The L-SM had the lowest response in terms of milk yield, but the highest in milk fat percentage, thus suggesting concentration effects. On the other hand, CM produced the lowest protein concentrations, probably because of differences in dietary amino acid supply to the mammary gland. Milk urea concentration was lowest for CM. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to evaluate dry matter intake (DMI), milk yield, and milk composition from feeding rations that contained different sources of genetically modified whole cottonseed to Argentinean Holstein dairy cows. Twenty-four lactating multiparous Argentinean Holstein dairy cows were used in 2 experiments with a replicated 4 x 4 Latin square design, with cows averaging 565 kg body weight and 53 d in milk at the beginning of the experiments. Treatments in Experiment 1 were: Bollgard cotton containing the cry1Ac gene, Bollgard II cotton containing cry1Ac and cry2Ab genes, Roundup Ready cotton containing the cp4 epsps gene, and a control nongenetically modified but genetically similar cottonseed. In Experiment 2, two commercial sources, a parental control line, and the transgenic cotton containing both cry1Ac and cp4 epsps genes were used as treatments. All cows received the same total mixed ration but with different whole cottonseed sources. Cottonseed was included to provide 2.50 kg per cow daily (dry matter [DM] basis) or about 10% of the total diet DM. The ingredient composition of the total mixed ration was 32% alfalfa hay, 28% corn silage, 22% corn grain, 17% soybean meal, and 2% minerals and vitamins. In addition, genomic DNA was extracted from a subset of milk samples and analyzed by polymerase chain reaction followed by Southern blot hybridization for small fragments of the cry1Ac transgene and an endogenous cotton gene, acp1. No sample was positive for transgenic or plant DNA fragments at the limits of detection for the assays following detailed data evaluation criteria. The DMI, milk yield, milk composition, body weight, and body condition score did not differ among treatments. Cottonseed from genetically modified varieties used in these studies yielded similar performance in lactating dairy cows when compared to non-transgenic control and reference cottonseed. [ABSTRACT FROM AUTHOR]