Effects of anion supplementation to low-potassium prepartum diets on macromineral status and performance of periparturient dairy cows.

Data from multiparous Holstein cows (n = 43) were used to determine whether supplementation of anions to low-potassium (K) prepartum diets would improve periparturient energy and macromineral status and affect performance during the postpartum period. Beginning 21 d before expected parturition, cows were fed a control diet (1.29% K; +10 mEq/100 g; n = 21) or a low dietary cation-anion difference (DCAD) diet (1.

The relative merit of ruminal undegradable protein from soybean meal or soluble fiber from beet pulp to improve nitrogen utilization in dairy cows.

Early lactating dairy cows were used to determine whether the replacement of solvent-extracted soybean meal [SSBM; a source of rumen-degradable protein (RDP)] with expeller soybean meal (ESBM; a source of rumen-undegradable protein), or the replacement of high-moisture shelled corn (HMSC) with beet pulp (a source of soluble fiber) would be effective in improving efficiency of N usage for milk production. The study was designed as a replicated 4 x 4 Latin square with 21-d periods. Eight multiparous Holstein cows were fed, ad libitum, the following diets, which were based on alfalfa silage and HMSC, and formulated to be isocaloric: 1) basal diet without a protein supplement (negative control diet: NC); 2) NC supplemented with solvent-extracted SBM (diet SSBM); 3) NC supplemented with expeller SBM (diet ESBM); 4) SSBM in which unmolassed dried beet pulp replaced half of the HMSC (diet SSBMBP).

Towards non-invasive methods to determine the effect of treatment of soya-bean meal on lysine availability in dairy cows.

Lysine (Lys) availability in three different soya-bean meal (SBM) products was determined using the following techniques: whole body (WB) net flux of Lys, digestible Lys (duodenal flow × intestinal digestibility) and the plasma Lys response curve method of Rulquin and Kowalczyk (2003). Four multiparous Holstein cows (173 days in milk) were equipped with ruminal and duodenal cannulas and used in a 4 × 4 Latin square experiment with 14-day periods. The animals were fed either solvent-extracted SBM (SE), expeller-processed SBM (EP) or lignosulphonate-treated SBM (LS) at 23% of the diet dry matter (DM).

Effect of timing of Cosynch on fertility of lactating Holstein cows after first postpartum and Resynch timed-AI services.

To compare two intervals from the PGF(2alpha) injection to the second GnRH injection+timed artificial insemination (TAI) of Ovsynch, lactating Holstein cows received their first postpartum TAI after Presynch + Ovsynch (n=352) and second and greater postpartum TAI after resynchronization of ovulation using Ovsynch (Resynch; n=458). Each week, cows housed in each of four breeding pens were randomized by breeding pen to receive the second GnRH injection of Presynch + Ovsynch or Resynch and TAI either 48 h (Cosynch 48; n=382) or 72 h (Cosynch 72; n=428) after the PGF(2alpha) injection of Ovsynch or Resynch. Overall, pregnancies per AI (P/AI) did not differ for cows receiving Cosynch 48 (29%) versus Cosynch 72 (33%).

Ruminal degradability and intestinal digestibility of protein and amino acids in treated soybean meal products.

Four lactating dairy cows equipped with ruminal and duodenal cannulas were used to determine the impact of different methods of treating soybean meal (SBM) on the ruminal degradability and intestinal digestibility of crude protein and AA. Solvent-extracted SBM (SE), expeller SBM (EP), lignosulfonate SBM (LS), and heat and soyhulls SBM (HS) were incubated in the rumen in nylon bags for 48, 24, 16, 8, 4, 2, and 0 h according to National Research Council (2001) guidelines. Additional samples of each SBM product were also incubated for 16 h in the rumen; the residues from these bags were transferred to mobile bags, soaked in pepsin HCl, and then used for determination of intestinal digestibility in situ or in vitro.

Feeding glycerol to transition dairy cows: effects on blood metabolites and lactation performance.

Glycerol can alleviate the symptoms of ketosis when delivered as an oral drench. The addition of glycerol to the diet would eliminate the need for restraining cows for drenching yet deliver a glucogenic substrate, alleviate the fatty liver-ketosis complex, and improve lactational performance. For this study, 21 multiparous and 9 primiparous Holstein cows blocked by parity and expected calving date were used in a randomized block design to evaluate the effects of feeding glycerol from 14 d prepartum to 21 d in milk (DIM).

Effect of prepartum dietary protein level on performance of primigravid and multiparous Holstein dairy cows.

This study compared the effects of two levels of crude protein (CP) fed during late gestation on the performance, blood metabolites, and ovarian activity of Holstein cows. One-hundred and six cows (42 primigravid and 64 multiparous) 32 d before calving were divided into two groups and fed diets containing moderate (12.7% CP, 36% rumen undegradable protein, (RUP) or high (14.

Evaluation of periparturient dairy cows and contact surfaces as a reservoir of Cryptosporidium parvum for calfhood infection.

Objective: To determine whether periparturient cows or contact surfaces to which newborn calves are exposed are reservoirs of Cryptosporidium parvum oocysts.

Animals: Periparturient cows and their calves.

Procedure: Using direct fluorescent antibody (DFA) and acid-fast (AF) assays, fecal samples taken before and after calving from periparturient cows were tested for C parvum oocysts.

Field testing of prophylactic measures against Cryptosporidium parvum infection in calves in a California dairy herd.

Objective: To test the ability of oral vaccination or probiotic treatment with lactic acid-producing bacteria to protect calves from Cryptosporidium parvum infection under field conditions.

Animals: 134 Holstein calves born on a dairy farm where cryptosporidiosis was endemic.

Procedure: Calves were randomly assigned to 1 of 3 treatment groups at birth.

Photodynamic effects of hypericin on lipid peroxidation and antioxidant status in melanoma cells.

Photodynamic-induced cytotoxicity by hypericin (HYP) was studied on three human melanoma cell lines: one pigmented cell line (G361) and two amelanotic cell lines (M18 and M6). No significant variation in the rate of uptake and in the maximum level of HYP incorporation for the different cells was observed. In the dark, no cytotoxicity was observed in the range 0-10-6 M HYP for the three cell lines.

Field trials of an oral calcium propionate paste as an aid to prevent milk fever in periparturient dairy cows.

Trials were conducted to test the efficacy of a calcium propionate paste as an aid to prevent milk fever and to improve the health of dairy cows. Each calcium propionate treatment tube supplied 37 g of calcium. In trials involving Holstein herds and a Jersey herd, two (trials 1 and 2) or three (trial 3) calcium propionate tubes were given at calving and again at 12 h after calving.

Photodynamically induced cytotoxicity of hypericin dye on human fibroblast cell line MRC5.

The possible application of hypericin (hyp) in the photodynamic therapy (PDT) of cancer was investigated using the human fibroblast cell line MRC5. In aerobic conditions, at pH 7.4, irradiation of MRC5 cells was carried out with different doses of visible light and different doses of hyp.

Screening for drug photosensitization activity by measuring the variations in oxygen consumption of Bacillus subtilis.

An original method is described for detecting the photosensitizing ability of a compound. The principle of this method is based on the analysis of variations in the consumption of oxygen by Bacillus subtilis (measured with Warburg's apparatus or an oxygenometric cell), induced by irradiation of the test compound added to the bacterial culture medium. This methodology was applied to 7 substances: 5 known photosensitizers (8-MOP, chlorpromazine, 5-fluorouracil, Vitamin A acid and benzoyl peroxide) and 2 products without any photoactive properties (aspirin and erythromycin).