Steam frothing of milk is required to produce an acceptable foam for many espresso coffee drinks. Specific aspects of composition and processing may affect the foaming properties of milk. The aim of this study was to determine the effect of fat content, heat treatment, free fatty acid addition and storage time on the frothing properties of milk. The four treatments included: fat content (0.08% and 3.25%), pasteurization temperatures (171°F for 15 seconds and 210°F for 45 seconds), pre and post-pasteurization addition of lauric acid solution (0.0% and 2.0% of 0.5 M concentration) and storage time (1 and 10 days). For this experiment, 3 replicates were performed. For each treatment, 250 ml of milk was frothed with a Feama Espresso machine (model c85/1) using a 7.5-cm diameter graduated beaker for 25 seconds. For each treatment, frothing was repeated 5 times. Froth characteristics were observed and the steam froth value (SFV), amount of dissipation and foam volume were determined after 5 minutes. The free fatty acid level (µ equiv./ml) for all treatments were also determined prior to frothing. There was no interaction found between day and treatments. There was no significant difference (P≥0.05) found between day 1 and day 10 for SFV, foam volume, or dissipation based on fat level, pasteurization temperature, or free fatty acid addition. When all treatments over time were observed, there was a significant difference (P<0.05) in SFV and FFA level (µ equiv./ml). There was a significant difference (P<0.05) in SFV, foam volume and percent dissipation between all free fatty acid levels when all other factors were applied.

Folic acid fortification is used in the prevention of neural tube defects such as spina bifida and ancencephaly, heart defects, facial clefts, urinary tract abnormalities, and limb deficiencies. Although yogurt is not a good source of folic acid, fortification could aid in prevention of above mentioned defects. Fortification of yogurt with folic acid may or may not change its physico-chemical characteristics. Fat free sugar free yogurt was manufactured using 0, 25%, 50%, 75% and 100% of the recommended daily allowance of 400 micrograms of folic acid. Treatments included addition of folic acid at these levels before and after pasteurization. Lemon and strawberry flavorings were added to improve flavor and improve color of yogurts. The objective was to examine the effects of folic acid on viscosity, pH, TA, syneresis, color, composition, and folic acid concentration in the product at one, three, and five week intervals. Data were analyzed using the General Linear Model procedure with a general linear model with repeated measures in time analysis by the Statistical Analysis System. Significant differences were determined at P<0.05 using Tukey's Studentized Range Test. There were no differences in the electrophoretic mobilities of the protein/peptides in the samples. Mean flavor scores were higher for lemon and strawberry yogurts as compared to plain when tested by a trained sensory panel. Folic acid fortification of yogurt impacted some of its physico-chemical attributes.

Two experiments were conducted to investigate the effects of free Met and Lys supplementation on ruminal fermentation in vitro and in vivo. In the in vitro study, supplementation of Met and Lys had effects on concentrations of total VFA and NH₄⁺, proportions of acetate, propionate, butyrate, isovalerate, valerate, and the ratio of acetate to propionate. Percentages of microbial N synthesis in effluent pellets were not affected by supplementing Lys and Met. The combination of 0.52% Met and 1.03% (90% DM) Lys resulted in the highest concentration of total VFA, second highest concentration of NH₄⁺, and lowest ratio of acetate to propionate with no decrease in the microbial CP production. In the in vivo study, supplementing 0.29% Met and 2.27% Lys (100% DM) had no impact on mean DMI, OMI, milk yield, milk component production or percentage, SCCS, 4% FCM and ECM production efficiencies, or body weight gain. Although DMI for the treatment group was numerically lower than the control group, milk yield, % milk fat, and % milk protein for the treatment group were numerically higher than the control group and resulted in numerically higher 4% FCM and ECM efficiencies for cows received AA supplementation. There was a statistical interaction of treatment and day observed on DMI, OMI, and 4% FCM and ECM production efficiencies indicating that the treatment group maintained a better production efficiency than the control group throughout the experiment. The concentration of ruminal NH₄⁺ and the proportion of butyrate were increased, but proportions of acetate and valerate were decreased while the pH, total VFA, proportions of propionate, isobutyrate and isovalerate, and the ratio of acetate to propionate were not affected by supplementing AA.

Considerable variation in the percentage of Y-chromosome bearing spermatozoa (%Y-CBS) between ejaculates in the same male has been reported. Collection regime has been speculated to influence the degree of variation in %Y-CBS in bull ejaculates (Chandler et al., 1998). Experiments were designed to evaluate the effects of two collection regimes on %Y-CBS. Conventional PCR combined with gel electrophoresis and image analysis was employed to determine %Y-CBS in ejaculates from two bulls collected on 7-day intervals and two bulls on 21-day intervals. Real-time PCR technology was used to quantify %Y-CBS in the same ejaculates. Boar ejaculates were also analyzed with both techniques and compared to the percent male piglets in litters resulting from the assayed ejaculates. Collection day (P<0.0001) significantly affected %Y-CBS as determined by both PCR methods. Ejaculate nested within bull (P<0.07) was significant in the conventional PCR study and collection frequency (P<0.0001) in the realtime PCR trial. Ejaculate nested within boar was highly significant (P<0.0001) for both technologies. Boar was significant (P<0.002) in the conventional PCR study. Predicted %Y-CBS determined by real-time PCR was significantly correlated (0.52, P=0.004) to percent male piglets. Both PCR techniques were effective in quantifying the variation in %Y-CBS in bull and boar ejaculates. Manipulation of %Y-CBS via collection regime may prove valuable for altering the secondary sex ratio in animal agriculture.

Mastitis in prepartum dairy heifers has been recognized as a significant economic problem for the dairy industry. Intramammary infusion of cephapirin sodium was completed in 20 treatment animals and the results were compared to 25 non-treated control animals. Bacteriological data from the quarter milk samples were used to determine and compare initial infection rates and cure rates following calving between treatment and control groups. Comparisons were also made between groups for differences in reproductive performance, milk yield, somatic cell count and milk ketone concentration. Milk yield did not differ between groups for either DHIA monthly average kg/day, 305 day actual milk yield or 305 day mature equivalent yield (305ME). The average weekly milk weights (kg/d) between groups were different (P<.0001). Reproductive performance between groups was not significantly different. Milk ketone concentration did not differ at weeks 1 or 2. Somatic cell count score (SCS) at 200 days in milk were not different between groups, but the treatment group exhibited a trend towards lower cell counts (P<.10). SCS in the treatment group tended to be lower (P<.09) during the average of the first 3 DHIA test periods. Prepartum treatment of dairy heifers significantly improved cure rates in the treatment group (P<.003), moderately reduced SCC throughout lactation, and did not affect milk yield. While there were no significant differences between treatment groups in milk ketone concentration, evidence suggests that infections caused by major mastitis pathogens may increase metabolic stress on primiparous heifers. Further research in the use of prepartum lactating cow antibiotics in heifers is needed.

Eight weaned Holstein steers approximately 4 mo of age (mean BW = 119.47 ± 2.65 kg) were used in a replicated 4 x 4 Latin square designed experiment to study the effects of protein source and level on performance and anabolic hormonal status of weaned dairy calves. Treatments consisted of two diets containing either 16 or 20 % crude protein (CP) with or without fish meal (FM). Experimental diets were corn silage based with soybean meal (SBM) as the source of ruminal degradable protein and FM as the source of ruminal undegradable protein. The animals were fed their respective diets twice daily at ad libitum levels during each 10-d adjustment period and 4-d sample collection period. Animals were housed in individual stalls for 10 d and in metabolism crates for 4 d for each experimental period. Feed intake was recorded daily. Total fecal and urine output were collected, weighed and subsampled during the 4-d sample collection period for laboratory analysis of nitrogen. On d 4 of the sample collection period, animals were fitted with indwelling jugular catheters. Blood samples were collected for 6 h at 15-min intervals for analysis of growth hormone (GH) and 30-min intervals for analysis of insulin (INS) and insulin-like growth factor-1 (IGF-1). An initial blood sample was taken at the beginning of the 6-h blood sample period for analysis of plasma urea nitrogen (PUN) and thyroxine (T4). On d 14 of the each experimental period, body weight, wither height, hip height, and body length were measured. Treatment did not affect (P > 0.10) dry matter intake, any of the growth parameters measured, or nitrogen balance. Steers consuming diets containing 20% CP diets tended to have higher plasma INS concentrations (P = 0.07) whereas steers consuming SBM as the protein source tended to have higher mean GH levels (P= 0.07). Thyroxine, IGF-1, and PUN concentrations were not effected by protein level or source (P > 0.10). It is concluded that feeding diets greater than 16% CP with or without FM does not improve performance in weaned dairy calves.

The experiments described herein are designed to elucidate many metabolic changes that occur to regulate the partitioning of nutrients between production and animal maintenance with particular regard to glucose metabolism and insulin sensitivity. The onset of milk production and parturition causes dramatic stress to the cow. The challenge of improving metabolism during this period is being addressed by nutritional management with the possibility of the addition of supplements. The use of Ca-propionate as a supplement did not affect glucose metabolism in transition cows. The data revealed that insulin sensitivity was low during the transition period, but the tissue responses to insulin and the acute insulin response to a glucose infusion increased slightly after calving as compared to late gestation. Glucagon and nonesterified fatty acid concentrations increased throughout the transition period, while glucose, insulin, and thyroxine concentrations decreased. A need for a relatively easy and inexpensive test for evaluating glucose metabolism has been indicated, and it was shown that the Minimal Model computer analysis of the frequently sampled glucose tolerance test was adequate in assessing insulin sensitivity in dairy cattle. The acute hyperinsulinemia induced by the insulin tolerance test or by the hyperinsulinemic euglycemic test did not affect plasma leptin concentrations.

Six non-lactating Holstein cows with ruminal and duodenal cannulas were used in a replicated 3x3 Latin square design experiment to investigate the effects of supplemental protein source on ruminal and total tract nutrient digestibility. Supplemental protein was provided from soybean meal (SBM), expeller processed soybean meal (EXP), or menhaden fish meal (FM). Basal diets consisted of (DM basis) 33% corn silage, 20% bermudagrass hay, 27% ground corn, and 2% minerals and vitamins. Supplemental protein was provided as (DM % of total diet) 18% soybean meal (SOY), 17% soybean meal and 1% fish meal (FM), or 12% soybean meal and 6% expeller processed soybean meal (EXP). Period length was 14 d. Flow of digesta was estimated using Cr₂O₃ as an external marker. Due to factors unrelated to the trial, one cow died during the first period of the study and was not replaced. Dry matter intake averaged 9.5 kg/d and was not affected by treatment. Apparent ruminal dry matter digestibility was not affected by source of supplemental protein. Source of supplemental protein did not affect apparent total tract dry matter digestibility. Feeding low ruminal degradable protein to non-lactating cows resulted in no appreciable impact on feed intake or apparent diet digestibility.

Thirty-nine ejaculates from 8 Holstein bulls were collected. Straws of semen (n=750) were distributed among dairies in three states. Ten straws per ejaculate were sent to Louisiana State University (LSU) Dairy Improvement Center for conventional polymerase chain reaction (PCR) analysis. Spermatozoal DNA was extracted and PCR analysis was done using one primer set amplifying a single copy 125 base pair (bp) section of the Bos taurus factor IX (Christmas factor) precursor (found on the X chromosome) and another primer set amplifying a single copy section of the Bos taurus sex determining region Y protein (SRY) gene (found on the Y chromosome). A 294 bp product from the Bos taurus glyceraldehydes-phosphate-dehydrogenase (GAPDH) was amplified as an internal control. Standard curves were designed using PCR products in known ratios. Gel electrophoresis and image analysis allowed for determination of predicted % Y chromosome-bearing spermatozoa (predicted % Y spermatozoa). Calf sex was reported and % male calves was determined between bull, ejaculate within bull, state, and location within state. Predicted % Y spermatozoa and % male calves showed significant correlation to each other. No significant variance between bull was found in predicted % Y spermatozoa or % male calves, but significant variance was found between ejaculate within bull for both. PCR technology used for determining the % Y spermatozoa in ejaculates was shown to be an adequate method to determine semen sex ratio.

Folic acid plays an important role in the prevention of neural tube defects such as spina bifida and anencephaly, heart defects, facial clefts, urinary abnormalities and limb deficiencies. Milk and milk products serve as a potential source for folic acid fortification due to the presence of folate binding proteins which seem to be involved in the folate bioavailability. Though milk is a not a good source of folic acid, fortification could help in the prevention of the above mentioned defects. The objective of this study was to examine the physico-chemical characteristics of reduced fat milks fortified with folic acid. Reduced fat milks were prepared using 25, 50, 75 and 100% of the recommended dietary allowance of 400 micrograms of folic acid. Treatments included addition of folic acid at these levels before and after pasteurization. Color, pH, fat, protein, viscosity, folic acid concentration, folate binding protein concentration, folate binding protein profile, standard plate count and coliform counts were determined on days 1, 7, 14 and 21. A consumer acceptance test was conducted on day 7. Data from the consumer panel was analyzed using analysis of variance (PROC GLM) with means separation to determine the differences among treatments. Data obtained from the color, pH, fat, protein, viscosity, folic acid concentration, folate binding protein concentration, standard plate count and coliform counts were analyzed using the General Linear Model with a repeated measure in time by the Statistical Analysis System. Significant differences were determined at P<0.05 using Tukeys Studentized Range Test. There were no differences in the electrophoretic mobility of folate binding protein in the samples. The concentration of folic acid was significantly higher in reduced fat milks fortified with folic acid after pasteurization compared to the treatments to which folic acid was added before pasteurization. The consumer panelists did not find any significant differences in flavor, appearance and texture of folic acid fortified reduced fat milks compared to that of the control. Fortification of reduced fat milks with folic acid can be accomplished with out adversely affecting the product characteristics.