Supplementation of rumen-undegradable protein to the diets of early lactation Holstein cows on grass pasture.

The objectives were to evaluate supplements differing in rumen-undegradable protein (RUP) on the performance of early lactation cows on grass pasture. Twenty-four Holstein cows averaging 68 d of lactation and 39.8 kg/d of milk were rotationally grazed on predominantly Dactylis glomerata pasture for 8 wk. Cows were blocked according to parity, milk yield, and days of lactation and were randomly assigned to a grain mixture with a low or high RUP content. Pasture and the low and high RUP grain mixtures averaged 25.6, 14.7, and 13.7% crude protein and 4.0, 7.0, and 8.4% RUP, respectively (dry matter basis). Grain was fed twice daily at 1 kg/4 kg of milk, pasture provided all forage in the diet, and grain consumption was similar (8.9 kg/d per cow) for cows on both treatments. Total dry matter intakes estimated using chromic oxide were 19.9 and 20.9 kg/d for cows fed low and high RUP grain mixtures. Milk yields did not differ between treatments; means were 34.2 and 35.5 kg/d for cows fed low and high RUP grain mixtures. Multiparous cows tended to yield more milk (36.2 vs. 34.5 kg/d) and milk protein (1.06 vs. 0.98 kg/d) when fed the high RUP grain mixture. Concentrations of plasma urea N and nonesterified fatty acids were unaffected by treatment and averaged 18.7 mg/dl and 307 microeq/L, respectively. Results indicated that a supplemental grain mixture with a high RUP content did not alter milk yield of high yielding cows when pasture was the sole forage; however, milk protein yield tended to be greater for multiparous cows fed the high RUP grain mixture.

Lamb wave scattering analysis for reflector characterization.

The potential use of guided waves for defect characterization is studied. The influence of defect shape and size on transmitted and reflected fields is considered. Using the hybrid boundary element technique, the reflection and transmission coefficients for selected guided wave modes are numerically calculated and compared to experimental data. Selecting the aspect ratio as a shape parameter for various defects, the transmission and reflection coefficients are measured for certain guided wave modes input to the defect. The influence of defect size is then studied by monitoring the transmission and reflection coefficients for defects of various shapes and depths. The studies presented indicate that defect characterization is possible if a proper mode selection criteria can be established. The suitable features related to transmission and reflection coefficient data can also be used for algorithm development and implementation purposes of defect characterization.

Evaluation of a mobile computerized grain feeder for lactating cows grazing grass pasture.

The objective of this study was to evaluate a mobile computerized grain feeder for use to feed individually Holstein cows grazing grass pasture. Thirty-two Holstein cows averaging 95 d of lactation and 39.3 kg/d of milk were rotationally grazed on predominantly Dactylis glomerata pastures for 9 wk starting in early May. Cows were blocked according to parity, days of lactation, and milk yield. Cows were randomly assigned to a control group in which cows were individually fed grain twice daily at milking or to a group that was offered grain four times daily using a mobile grain feeder in the pasture. Cows in both groups were offered 1 kg of grain/3 kg of milk; pasture was the only source of forage. Cows fed using the mobile grain feeder consumed less grain than did control cows (9.3 vs. 11.3 kg/d) and tended to yield less milk, but with a higher fat content. A separate analysis was conducted using data from only those cows that were fed using the mobile grain feeder and that consumed, in four relatively equal amounts, at least 75% of the allotted grain of their respective pairmates (7 per group) in the control group. When cows that were using the mobile grain feeder consumed amounts of grain comparable with that of the controls, more frequent grain feeding did not alter milk yield or composition. Plasma samples (five per cow per treatment) were collected at 2-wk intervals to measure glucose, urea N, and nonesterified fatty acids (NEFA). Plasma glucose and urea N were not affected by treatment and averaged 54.9 and 19.9 mg/ dl for all cows, respectively. Cows fed grain using the mobile feeder had higher (212.4 vs. 170.5 meq/L) concentrations of NEFA than did control cows, but, when cows consumed greater than 75% of their allotted grain from the mobile feeder, concentrations of NEFA were similar. The mobile grain feeder can be used to feed cows individually on pasture; however, adaptation of the cows to the mobile grain feeder appears to be important.

Effect of fish meal and expeller-processed soybean meal fed to dairy cows receiving bovine somatotropin (sometribove).

Forty-eight multiparous cows were blocked by calving date and milk production and assigned randomly to a TMR formulated to contain 68 or 55% of dietary CP as ruminally degradable CP. Diets contained corn silage, alfalfa haylage, and ground corn. Supplemental CP was soybean meal for the control diet or a combination of soybean meal, expeller-processed soybean meal, and fish meal for the low degradable protein diet. Two 10-wk phases began on d 31 +/- 3 (phase 1) and 110 +/- 7 postpartum [phase 2, all cows received subcutaneous implantations of pelleted (400 mg) bST (sometribove) every 14 d]. Dietary energy, CP, ruminally degradable CP, NDF, and ADF were similar between dietary treatments. Production of FCM increased in response to bST but was not affected by dietary treatment. Cows fed the expeller-processed soybean meal and fish meal TMR produced milk that contained less milk fat in phase 1 and less milk protein content in both phases. The DMI, BW, and body condition scores were not affected by diet. Hematocrit, plasma urea N, albumin, total protein, creatinine, glucose, and serum insulin were similar between dietary treatments. Replacing soybean meal with expeller processed soybean meal and fish meal did not affect ruminal degradation of protein or milk production but decreased milk fat and protein contents.

Effects of a growth hormone-releasing factor analogue and an estradiol-trenbolone acetate implant on somatotropin, insulin-like growth factor I, and metabolite profiles in growing Hereford steers.

Hereford steers (290 +/- 6 kg of BW) were implanted (n = 4) with 140 mg of trenbolone acetate (TBA) and 28 mg of estradiol-17 beta (E2 beta) or nonimplanted (controls, n = 4). In Trial 1, effects of a single i.v. injection of 0, 20, 40, or 80 micrograms of a growth hormone-releasing factor (1-29 NH2) analogue (GRFa) on release of endogenous somatotropin (ST) were evaluated in a double 4 x 4 Latin square design. Plasma samples (n = 21) were obtained from -20 to 240 min after GRFa injection. Area under the ST response curve (AUC) increased (P = .009) in a dose-dependent manner (.2, 2.6, 3.6, 4.3 mg.min-1.mL-1, respectively). Mean ST concentration was not affected (P = .238) by implant but AUC was greater (P = .009) in implanted than in control steers. There was no interaction (P = .460) between dose of GRFa and presence of implant. In Trial 2, 80 micrograms of GRFa was administered at 12-h intervals to the same eight steers. Response of ST (AUC) to the first and last (13th) i.v. injection of GRFa was similar and not affected by implant. Before GRFa administration, plasma insulin-like growth factor I (IGF-I) concentrations were greater (P = .039) in implanted than in control steers (272 vs 164 ng/mL). Administration of GRFa increased plasma IGF-I (P = .0001), decreased plasma urea N (PUN) (P = .0001), and did not alter plasma glucose (P = .447) in both control and implanted steers. Data indicate that effects of GRFa and TBA/E2 beta on plasma IGF-I and PUN concentrations were additive in this study.