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The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein × Jersey crossbred cows with an average of 146 ± 50 DIM, 575.4 ± 70 kg of BW, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3 × 3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced DM, CP, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest BW was observed for cows fed 50E+100P, with no difference for BCS. During the induction phase, MES was reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, whereas 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and SCS, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

The aim of this research was to evaluate the risk factors for new and chronic subclinical intramammary infections (IMI) using the monthly somatic cells count of dairy cows. The study took place at 30 dairy herds with approximately 1,700 cows in lactation. Data characterizing the dairy farms and their milking management were obtained from a survey questionnaire. The somatic cells count values from 2 consecutive months were used to classify cows as either healthy or with new or chronic infections. A chi-squared test was used in the analysis of subclinical IMI to evaluate associations between each independent variable, followed by logistic regression to estimate the risk of a new infection in healthy cows and of chronic infection in cows with new infections. Factors increasing the odds ratio of a cow developing a new case of subclinical mastitis were (1) cows with more than 3 lactations, (2) cows with a mean hyperkeratosis score above 3, (3) cows with the udder below the hock, (4) cows with very dirty udders, and (5) milking of infected animals before healthy cows. Factors increasing the risk of a subclinical chronic infection compared with new cases of subclinical mastitis were (1) a lack of regular maintenance of milking machinery, (2) cows over 100 d in lactation, and (3) cows with the udder on or below the hock. The risk factors identified in this study can be used in IMI control programs to reduce the frequency of new and chronic cases of subclinical mastitis., (Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)