Rumen degradable protein levels on fatty acid profile of rumen bacteria and milk fat of dairy cows supplemented with calcium salts of fatty acids.

This study aimed to evaluate the effects of calcium salts of fatty acids (CSFA) from soybean oil in diets with different levels of rumen degradable protein (RDP) on bio-hydrogenation extent, and fatty acid (FA) profile intake, omasal digesta, rumen bacteria, and milk fat. Eight Holstein lactating cows were used in a replicated 4 × 4 Latin square design. Treatments were arranged in a 2 × 2 factorial design with two CSFA levels (0 or 33.2 g/kg DM of CSFA) and two RDP levels (98.0 or 110 g/kg DM). There was RDP and CSFA interaction effect on the omasal flow of total FA and some specific FA. Only in -CSFA diets, the higher RDP level increased omasal flow of total FA. Dietary RDP levels did not affect the FA profile of bacteria and milk fat. Feeding CSFA reduced or tended to reduce the bacterial proportion of C15:0, C16:0, C16:1, C17:0, and C18:0 FA and decreased the concentrations of short- and medium-chain FA (<18C) and increased the concentrations of unsaturated and long-chain FA (≥18C) in milk fat. Feeding CSFA of soybean oil increases the intake and omasal flow of FA and augments unsaturated FA content in bacteria pellets and milk fat.

Influence of different growing stages of whole-plant soybeans on their nutrient content and silage quality for cattle.

The objective of this study was to determine the effects of growing stage (GS) on morphological and chemical composition of whole-plant soybean (WPS), and fermentative profile and chemical composition of whole-plant soybean silage (SS). This study was divided into two trials conducted in a complete randomised block design. The first trial evaluated the effect of GS from R1 to R8 (59-135 d after sowing) on morphological and chemical composition of WPS and its botanical components. The second trial determined the effects of GS from R3 (71 d after sowing) to R7 (124 d after sowing) on dry matter (DM) losses, fermentative profile, chemical composition and aerobic stability of SS. The proportion of leaves in WPS was reduced, while stem and pod proportions were increased as the GS progressed. Ensiling WPS at R6 and R7 decreased the contents of acetic acid, lactic acid and branched-chain fatty acids, and ethanol, and increased the contents of propionic acid and NH3-N. However, silage butyric acid concentrations in R6 and R7 were relatively high (18.1 and 19.9 g/kg DM, respectively). Butyric acid and buffering capacity varied according to GS with the lowest values observed in silages derived from GS R3, R5 and R7, and the highest values observed in silages made from GS R5. Later GS resulted in greater contents of DM, crude protein and ether extract, and lower contents of acid detergent fibre and non-fibre carbohydrate in SS. The high fat of SS produced from later GS limits high inclusion levels in ruminant diets. Morphological components impacted chemical composition of SS, whereas the R7 stage improved fermentative profile and resulted in an SS with greater in situ degradability of DM and neutral detergent fibre.

Association between Mastitis Occurrence in Dairy Cows and Bedding Characteristics of Compost-Bedded Pack Barns.

Compost-bedded pack barns (CB) are receiving increasing attention as a housing system that can potentially improve the welfare of dairy cows. This study characterized the frequency and profile of pathogens isolated from clinical (CM) and subclinical (SCM) mastitis in dairy cows housed in CB. It evaluated the association between mastitis occurrence and bedding characteristics in CB systems. Over six months, seven dairy herds were visited monthly for milk and bedding sample collections. Milk samples from mastitis cases were submitted to microbiological identification by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF MS). Bedding samples were submitted to physical-chemical (pH, organic matter, moisture, and carbon to nitrogen ratio) and microbiological counting (total bacterial counts, coliforms, streptococci, and staphylococci) analyses. Regression analysis was used to determine the association between mastitis occurrence and CB characteristics. Our results showed that Escherichia coli and environmental streptococci were the most frequently isolated pathogens from CM cases, while Staphylococcus chromogenes and contagious pathogens (Staphylococcus aureus and Streptococcus agalactiae) were the most commonly isolated from SCM cases. Bedding moisture content was positively associated with the incidence of CM. The bedding carbon to nitrogen ratio was negatively associated with the incidence of SCM, and the bedding total bacteria counts tended to be associated with the incidence of SCM. Bedding counts of coliforms positively associated with the prevalence of SCM. Our results can support decision-makers in the dairy industry seeking strategies for bedding management and mastitis control.