A total of twelve lactating Jersey cows were used in a 5-week experiment to determine the effects of severe feed restriction on the permeability of mammary gland cell tight junctions (TJs) and its effects on milk stability to the alcohol test. During the first 2 weeks, cows were managed and fed together and received the same diet according to their nutritional requirements (full diet: 15 kg of sugar cane silage; 5.8 kg of alfalfa hay; 0.16 kg of mineral salt and 6.2 kg of concentrate). In the 3rd week, animals were distributed into two groups of six cows each. One group received the full diet and the other a restricted diet (50% of the full diet). In the 4th and 5th weeks, all animals received the full diet again. Milk composition and other attributes, such as titratable acidity, ethanol stability, pH, density and somatic cell count (SCC) were evaluated. Cortisol levels indicated the stress condition of the cows. Plasma lactose and milk sodium were measured to assess mammary TJ leakiness. Principal factor analysis (PFA) showed that the first two principal factors (PFs) contributed with 44.47% and 20.57% of the total variance in the experiment and, as feeding levels increased, milk stability to the ethanol test became higher and plasma lactose levels decreased, which indicates lower permeability of the mammary gland cell TJ. Correspondence analyses were consistent with PFA and also showed that lower feeding levels were related to reduced milk stability, high plasma lactose, high sodium in milk, low milk lactose (another parameter used to assess TJ permeability) and higher cortisol levels, indicating the stress to which animals were submitted. All observations were grouped in three clusters, with some of the above-mentioned patterns. Feeding restriction was associated with higher permeability of TJ, decreasing milk stability to the ethanol test.

The aim of this study was to determine the effect of butaphosphan and cyanocobalamin (BTPC) supplementation on plasma metabolites and milk production in postpartum dairy cows. A total of fifty-two Holstein cows were randomly assigned to receive either: (1) 10 ml of saline (NaCl 0.9%, control group); (2) 1000 mg of butaphosphan and 0.5 mg of cyanocobalamin (BTPC1 group); and (3) 2000 mg of butaphosphan and 1.0 mg of cyanocobalamin (BTPC2 group). All cows received injections every 5 days from calving to 20 days in milk (DIM). Blood samples were collected every 15 days from calving until 75 DIM to determine serum concentration of glucose, non-esterified fatty acids (NEFA), b-hydroxybutyrate (BHB), cholesterol, urea, calcium (Ca), phosphorus (P), magnesium (Mg), aminotransferase aspartate (AST) and g-glutamyltransferase (GGT). The body condition score (BCS) and milk production were evaluated from calving until 90 DIM. Increasing doses of BTPC caused a linear reduction in plasma concentrations of NEFA and cholesterol. Supplementation of BTPC also reduced concentrations of BHB but it did not differ between the two treatment doses. Milk yield and milk protein had a linear increase with increasing doses of BTPC. A quadratic effect was detected for milk fat and total milk solids according to treatment dose, and BTPC1 had the lowest mean values. Concentrations of glucose, urea, P, Mg, AST, GGT, milk lactose and BCS were not affected by treatment. These results indicate that injections of BTPC during the early postpartum period can reduce NEFA and BHB concentrations and increase milk production in Holstein cows.Keywords: butaphosphan, cyanocobalamin, postpartum dairy cows, non-esterified fatty acid ImplicationsThis study presents a new metaphylactic strategy aimed to reduce the intensity of negative energy balance (NEB) in postpartum dairy cows. Unlike previous studies, the current protocol consists of five injections of cyanocobalamin and butaphosphan at 5 days interval during the first 20 days in milk (DIM), the period of greatest metabolic challenge for dairy cows. The results of this experiment indicate that this protocol can improve metabolic adaptation in the early postpartum period, by reducing adipose tissue mobilization and increasing milk production.

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Polymorphonuclear leukocytes (PMNL) are the first responders upon pathogen invasion and hence play an important role in inflammatory and immune responses. Rumen-protected methionine (MET) and choline (CHOL) during the peripartal period affect the immune response and inflammatory status in dairy cows to different extents. We aimed to examine the effect of MET and CHOL supply on expression of genes regulating key PMNL functions and associations with whole-blood immune challenge. Thirty multiparous Holstein cows from a larger cohort randomly assigned from -21 to 30 d relative to parturition to a basal control (CON) diet, CON plus MET at a rate of 0.08% of dry matter, or CON plus CHOL at 60 g/d were used. Blood was sampled at -10, 7, and 30 d relative to parturition for inflammatory biomarker analyses and PMNL isolation. Neutrophil and monocyte phagocytosis and oxidative burst in vitro were assessed in whole blood at 1, 7, and 28 d. Although neutrophil and monocyte phagocytosis did not differ, oxidative burst in neutrophils and monocytes was greater in MET-supplemented cows relative to CON cows. Compared with CON, PMNL adhesion and migration-related genes (ITGAM, ITGB2, ITGA4) were downregulated in response to MET and CHOL. Expression of CADM1 and SELL was also lower in MET-supplemented cows compared with CON cows but not in CHOL cows. In contrast, compared with CON cows, the expression of ICAM1 was lower in CHOL but not MET cows. Similar to adhesion and migration-related genes, cows receiving MET- or CHOL-supplemented diets had lower expression of inflammation-related genes (IL1β, IL10RA, NFKB1, STAT3, TLR2). However, expression of IRAK1 and TLR4 was lower in MET- but not CHOL-supplemented cows. Plasma taurine concentration was greater in MET cows compared with CHOL and CON cows, suggesting a better redox status in plasma. In agreement with plasma taurine, oxidative stress-related genes (CBS, CTH, GPX1, GSS, SOD2) in PMNL were lower in response to MET and to CHOL supply. Overall, immunometabolic gene expression profile and blood biomarker analyses suggest an overall better redox status in PMNL during the transition period in response to MET and CHOL supply. These adaptations in PMNL might be beneficial for mounting a better bactericidal response upon challenge.

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The aim of this study was to determine the effect of prepartum somatotropin injection in late-pregnant Holstein heifers on metabolism, milk production and resumption of postpartum ovulation. For this study, 31 late-pregnant Holstein heifers were used. The heifers were assigned randomly into two treatments: (1) 500 mg sc injections of somatotropin (somatotropin treatment, n 5 15) at 235 and 221 days, and, if pertinent, at 27 days from expected calving date and (2) no treatment (control group, n 5 16). Blood samples were collected weekly from 25 to 7 weeks after calving. Heifers with progesterone concentrations in plasma above 1 ng/ml in two consecutive postpartum samples were considered as having resumed ovarian activity. A higher proportion (P 5 0.04) of heifers treated with somatotropin resumed ovarian activity in the first 7 weeks post partum (73.3%; 11/15) compared with the control group (37.5%; 6/16). A higher number (P 5 0.02) of heifers in the somatotropin treatment group also ovulated during the first postpartum follicular wave (53.3%; 8/15) compared with the control group (12.5%; 2/16), as indicated by the number of heifers ovulating in the first 3 weeks post partum. Pregnancy rate was not affected by treatments (P . 0.10) and averaged 40.0% (6/15) in somatotropin-treated and 25.0% (4/16) in control heifers when evaluated up to 150 days in milk. Somatotropin treatment increased the average daily milk production by 2.8 kg/cow per day (P , 0.0001) and reduced the somatic cell count (P 5 0.009). Plasma IGF-I was higher (P , 0.05) for somatotropin-treated heifers in the prepartum period. Insulin and body condition score were higher (P , 0.05) and non-esterified fatty acids were lower (P , 0.05) for somatotropin-treated cows in the early postpartum period. In conclusion, somatotropin injection during the prepartum period in late-pregnant Holstein heifers was able to increase the proportion of heifers resuming ovarian activity early post partum, inspite of higher milk production.Keywords: bST, dairy heifers, IGF-I, ovarian activity, primiparous ImplicationsPhysiological changes during the transition period can have a great impact on health and performance. In our study, prepartum injection of somatotropin reduced negative energy balance (NEB) intensity as indicated by several metabolic markers evaluated in the postpartum period. A more intense NEB is usually associated with a delay in resumption of normal ovarian function. In this way, we observed a higher proportion of somatotropin-treated heifers ovulating earlier.Moreover, cows treated with somatotropin prepartum increased milk production. Along with earlier resumption of estrous cycles, this strategy can have an important impact on farm profitability. IntroductionDuring the early postpartum period, high-producing cows experience a period of negative energy balance (NEB) that occurs as the requirements for milk production exceed the -E-mail: augusto.schneider@live.com 935 energy obtained through feeding (Butler, 2003). In early postpartum dairy cows, the du...

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