Energy and protein levels in dairy cow diets to recover milk ethanol stability.

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.

Perfil metabólico de vacas Holandês e mestiças Holandês x Jersey no periparto / Metabolic profile of Holstein and crossbred Holstein x Jersey cows in the peripartum

O objetivo do presente trabalho foi determinar e comparar o perfil metabólico de vacas Holandês (H) e mestiças Holandês x Jersey (HxJ) no periparto. Avaliaram-se 24 vacas, sendo 11 vacas Holandês e 13 mestiças Holandês x Jersey. Semanalmente, coletou-se sangue para a determinação das concentrações séricas de glicose, beta-hidroxibutirato (BHB), proteína total, albumina, aspartato aminotransferase (AST), creatinoquinase (CK), cálcio total, cálcio iônico, magnésio, fósforo inorgânico e colesterol. Avaliou-se também o peso vivo e o escore de condição corporal (ECC). Os dados foram submetidos à análise de variância com medidas repetidas no tempo. As vacas Holandês apresentaram maior peso vivo. Não houve diferença entre os grupamentos genéticos para ECC. Foi observada tendência de maiores concentrações séricas de BHB, AST e maior concentração de cálcio iônico em vacas mestiças Holandês x Jersey. Vacas mestiças Holandês x Jersey e Holandês apresentaram perfil energético similar durante o período de transição pré e pós-parto na maioria dos indicadores, com exceção do cálcio, que foi maior nas vacas mestiças, e do fósforo, que foi superior nas vacas Holandês.(AU)

The aim of this study was to determine and compare the metabolic profile of Holstein (H) and crossbred Holstein x Jersey (HxJ) on peripartum. For this, 24 cows were evaluated, 11 Holstein and 13 crossbreeds Holstein x Jersey. Weekly, venous blood sample were collected to determine concentration of glucose, beta-hydroxybutyrate (BHBA), total protein, albumin, aspartate aminotransferase (AST), creatine kinase (CK), total calcium, ionic calcium, magnesium, inorganic phosphorus and cholesterol. Body weight (BW) and body condition score (BCS) were also evaluated. The data were submitted to analysis of variance with repeated measures in time. Holstein cows presented higher BW, however, there was no difference for BCS in compare to crossbreed Holstein x Jersey cows. Tendency for higher serum concentrations of BHBA, AST and higher concentration of ionic calcium was observed in crossbreed cows in comparison to the Holstein. The energetic profile during the pre and postpartum transition period is similar for both genetic groups with higher concentrations of BHBA on the first week of lactation, however, with a tendency of higher serum concentrations of BHBA for crossbreed cows. Higher concentrations of ionic calcium were observed in crossbreed cows and higher concentrations of phosphorus in Holstein cows on peripartum. Holstein and Holtein x Jersey crossbreed cows have a similar energy profile during the pre and postpartum transition period in most of the indicators, except for calcium that was higher in crossbred cows and higher phosphorus in Holstein cows.(AU)