Technical note: A proposed method to determine the extent of degradation of a feed in the rumen from the degradation profile obtained with the in vitro gas production technique using feces as the inoculum

A method is proposed to determine the extent of degradation in the rumen involving a two-stage mathematical modeling process. In the first stage, a statistical model shifts (or maps) the gas accumulation profile obtained using a fecal inoculum to a ruminal gas profile. Then, a kinetic model determines the extent of degradation in the rumen from the shifted profile. The kinetic model is presented as a generalized mathematical function, allowing any one of a number of alternative equation forms to be selected. This method might allow the gas production technique to become an approach for determining extent of degradation in the rumen, decreasing the need for surgically modified animals while still maintaining the link with the animal. Further research is needed before the proposed methodology can be used as a standard method across a range of feeds.

Chemical composition and fermentation characteristics of grain and different parts of the stover from maize land races harvested at different growing periods in two zones of central Mexico

The objective of this work was to determine the rumen fermentation characteristics of maize land races used as forage in central Mexico. In vitro gas production (ml per 200 mg dry matter (DM)) incubations were carried out, and cumulative gas volumes were fitted to the Krishnamoorthy et al. (1991) model. The trial used a split-plot design with cultivation practices associated with maize colour (COL) as the main plot with three levels: white, yellow and black maize; growing periods (PER) were the split plots where PER1, PER2 and PER3 represented the first, second and third periods, respectively and two contrasting zones (Z1 = valley and Z2 = mountain) were used as blocking factors. The principal effects observed were associated with the maturity of the plants and potential gas production increased (P < 0.05) in stems (PER 1 = 51.8, PER2 = 56.3, PER3 = 58.4 ml per 200 mg DM) and in whole plant (PER 1 = 60.9, PER2 = 60.8, PER3= 70.9 ml per 200 mg DM). An inverse effect was observed with fermentation rates in leaves (P < 0.01) with 0.061, 0.053 and 0.0509 (per h) and in whole plant (P < 0.05) with 0.068, 0.057, 0.050 (per h) in PER1, PER2 and PER3 respectively. The digestibility of the neutral-detergent fibre (NDF) decreased with maturity especially in leaves (P < 0.05) with values of 0.71, 0.67 and 0.66 g/kg; in rachis (P < 0.01) 0.75, 0.72, and 0.65 in PER1, PER2 and PER3 respectively. The NDF content in leaves in leaves (668, 705 and 713 g/kg DM for PER1, PER2 and PER3, respectively), stems (580, 594 and 644 g/kg DM) and, husk (663, 774 and, 808 g/kg DM) increased (P < 0.05) with increasing plant maturity, rachis were significantly different between periods (P < 0.01). The structure with-the best nutritive characteristics was the husk, because it had the lowest fibre contents, especially in acid-detergent lignin, with values of 22.6, 28.6 and 37.6 g/kg DM in PER1, PER2 and PER3, respectively.

Splanchnic metabolism of dairy cows during the transition from late gestation through early lactation

Blood flow and net nutrient fluxes for portal-drained viscera (PDV) and liver ( total splanchnic tissues) were measured at 19 and 9 d prepartum and at 11, 21, 33, and 83 d in milk ( DIM) in 5 multiparous Holstein-Friesian cows. Cows were fed a grass silage-based gestation ration initially and a corn silage-based lactation ration peripartum and postpartum. Meals were fed at 8-h intervals and hourly (n = 8) measures of splanchnic metabolism were started before ( 0730 h and 0830 h) feeding at 0830 h. Dry matter intakes (DMI) at 19 and 9 d prepartum were not different. Metabolism changes measured from 19 to 9 d prepartum were lower arterial insulin and acetate, higher arterial nonesterified fatty acids and increased net liver removal of glycerol. After calving, PDV and liver blood flow and oxygen consumption more than doubled as DMI and milk yield increased, but 85 and 93% of the respective increases in PDV and liver blood flow at 83 DIM had occurred by 11 DIM. Therefore, factors additional to DMI must also contribute to increased blood flow in early lactation. Most postpartum changes in net PDV and liver metabolism could be attributed to increases in DMI and digestion or increased milk yield and tissue energy loss. Glucose release was increasingly greater than calculated requirements as DIM increased, presumably as tissue energy balance increased. Potential contributions of lactate, alanine, and glycerol to liver glucose synthesis were greatest at 11 DIM but decreased by 83 DIM. Excluding alanine, there was no evidence of an increased contribution of amino acids to liver glucose synthesis is required in early lactation. Increased net liver removal of propionate (69%), lactate (20%), alanine (8%), and glycerol (4%) can account for increased liver glucose release in transition cows from 9 d before to 11 d after calving.

Visceral tissue mass and rumen volume in dairy cows during the transition from late gestation to early lactation

The objectives were to measure the effects of transition and supplemental barley or rumen-protected protein on visceral tissue mass in dairy cows and the effects of transition and barley on rumen volume and liquid turnover. Cows were individually fed a grass silage-based gestation ration to meet energy and protein requirements for body weight stasis beginning 6 wk before expected calving. A corn silage-based lactation ration was individually fed ad libitum after calving. In the visceral mass study, 36 cows were randomly assigned to one of 3 dietary treatments: basal ration or basal ration plus either 800 g dry matter (DM) of barley meal per day or 750 g DM of rumen-protected soybean protein per day. Cows were slaughtered at 21 and 7 d before expected calving date or at 10 and 22 d postpartum. Visceral mass and rumen papillae characteristics were measured. Diets had little effect on visceral mass. The mass of the reticulo-rumen, small intestine, large intestine, and liver was, or tended to be, greater at 22 d postpartum but not at 10 d postpartum before DM intake had increased. Rumen papillae mass increased at 10 d postpartum, perhaps in response to increased concentrates. Mesenteric fat decreased after calving, reflecting body fat mobilization. Ten rumen-cannulated cows were fed the basal gestation ration alone or supplemented with 880 g of barley meal DM. Rumen volumes and liquid dilution rates were measured at 17 and 8 d before calving and at 10, 20, and 31 d postpartum. Feeding barley had no effects. After calving, rumen DM volume and liquid dilution rate increased, but liquid volume did not increase. Changes in gastrointestinal and liver mass during transition were apparently a consequence of changes in DM intake and nutrient supply and not initiation of lactation per se.

Expressions and activities of cell cycle regulatory molecules during the transition from myocyte hyperplasia to hypertrophy

The role of cell cycle dependent molecules in controlling the switch from cardiac myocyte hyperplasia to hypertrophy remains unclear, although in the rat this process occurs between day 3 and 4 after birth. In this study we have determined (1) cell cycle profiles by fluorescence activated cell sorting (FACS); and (2) expressions, co-expressions and activities of a number of cyclins, cyclin-dependent kinases (CDKs) and CDK inhibitors by reverse transcriptase-polymerase chain reaction (RT-PCR), immunoblotting andin vitrokinase assays in freshly isolated rat cardiac myocytes obtained from 2, 3, 4 and 5-day-old animals. The percentage of myocytes found in the S phase of the cell cycle decreased significantly during the transition from hyperplasia to hypertrophy (5.5, 3.5, 2.3 and 1.9% of cells in 2-, 3-, 4- and 5-day-old myocytes, respectively,P<0.05), concomitant with a significant increase in the percentage of G0/G1phase cells. At the molecular level, the expressions and activities of G1/S and G2/M phase acting cyclins and CDKs were downregulated significantly during the transition from hyperplasia to hypertrophy, whereas the expressions and activities of G1phase acting cyclins and CDKs were upregulated significantly during this transition. In addition, p21CIP1- and p27KIP1- associated CDK kinase activities remained relatively constant when histone H1 was used as a substrate, whereas phosphorylation of the retinoblastoma protein was upregulated significantly during the transition from hyperplasia to hypertrophy. Thus, there is a progressive and significant G0/G1phase blockade during the transition from myocyte hyperplasia to hypertrophy. Whilst CDK2 and cdc2 may be pivotal in the withdrawal of cardiac myocytes from the cell cycle, CDK4 and CDK6 may be critical for maintaining hypertrophic growth of the myocyte during development.

Deconvolution method for removing the distortion from time jitter in equivalent-time waveform samplers

A sampling oscilloscope is one of the main units in automatic pulse measurement system (APMS). The time jitter in waveform samplers is an important error source that affect the precision of data acquisition. In this paper, this kind of error is greatly reduced by using the deconvolution method. First, the probability density function (PDF) of time jitter distribution is determined by the statistical approach, then, this PDF is used as convolution kern to deconvolve with the acquired waveform data with additional averaging, and the result is the waveform data in which the effect of time jitter has been removed, and the measurement precision of APMS is greatly improved. In addition, some computer simulations are given which prove the success of the method given in this paper.

The findings from a single pass deghoster prototype for terrestrial transmitted video

A deterministic prototype video deghoster is presented which is capable of calculating all the multipath channel distortion characteristics in one single pass and subsequently removing the multipath distortions, commonly termed ghosts. Within the system, a channel identification algorithm finds in isolation all the ghost components while a dedicated DSP filter subsystem is capable of removing ghosts in real time. The results from the system are presented.