Age at first calving and productive performance of primiparous Holsteins.

This study investigated the age at first calving in Holstein heifers and its impact on various production parameters. A sample of 737 Holstein heifers born between 2015 and 2018 and finishing their first lactations between 2018 and 2020 was included. Cluster analysis revealed three groups based on age at first calving: high precocity, medium precocity and low precocity.

Effects of Black Wattle () Condensed Tannins on Intake, Protozoa Population, Ruminal Fermentation, and Nutrient Digestibility in Jersey Steers.

The objective of this study was to evaluate the effect of inclusion of condensed tannins (CT) from black wattle () on feed intake, ruminal protozoa population, ruminal fermentation, and nutrient digestibility in Jersey steers. Five ruminally-cannulated steers were used in a 5x5 Latin square design, with five periods of 20 days each (14 days for diet adaptation and six days for sample collection per period). Treatments were composed of dietary inclusion levels of condensed tannins at 0, 5, 10, 15, and 20 g/kg of diet dry matter.

Black Wattle () Condensed Tannins as Feed Additives to Lactating Dairy Cows.

The objective of this study was to evaluate the effects of five levels of condensed tannins (CT) from black wattle () in the diets of lactating dairy cows on intake, nutrient digestibility, ruminal microbial protein synthesis, milk production, composition, oxidative profile, and blood metabolites. Five Holstein cows (88 ± 26.8 days in milk) were allocated in a 5 x 5 Latin square design for a period of 20 days (14 days of diet adaptation and six for sampling).

Use of dried waste of cassava starch extraction for feeding lactating cows.

The aim of this study was to determine the best level of utilization of dried waste of cassava starch extraction (WCSEd) as a substitute for corn for lactating cows. Four lactating cows were fed diets with increasing levels (0%, 33%, 66% and 100%) of WCSEd as a substitute for corn. The intake and digestibility of dry matter and nutrients, milk production and composition, blood parameters of glucose and urea and microbial synthesis of the diets were evaluated.