Perinatal ontogeny of brain growth in the domestic pig.

The perinatal development of the brain is highlighted by a growth spurt whose timing varies among species. The growth of the porcine cerebrum was investigated from the third trimester of gestation (70 days postconception) through the first 3.5 weeks of postnatal life (140 days postconception). The shape of the growth curves for cerebrum weight, total protein mass, total cell number (estimated by DNA content), and myelination (estimated by cholesterol accretion) were described. The growth velocity of cerebrum weight had two peaks, one at 90 days and the other at 130 days postconception, whereas that of total protein was greatest from 90 to 130 days postconception, and that of total DNA was greatest between 90 and 110 days and again at 130 days postconception. The growth velocity for total cholesterol continued to increase during the entire period, suggesting that myelination continued after the growth spurts for cells (protein and DNA). The growth velocity patterns observed in these contemporary pigs suggest that this species may be an appropriate model for human brain development, not only in the perinatal pattern of increase in mass of the cerebrum, as established previously, but also with regard to the patterns of cellular development and myelination.

Pigs fed cholesterol neonatally have increased cerebrum cholesterol as young adults.

Sixty-eight female neonatal pigs selected for seven (Experiment 1) or eight (Experiment 2) generations for high (HG) or low (LG) plasma cholesterol were used to test the hypothesis that neonatal dietary cholesterol fed during the first 4 or 8 wk of postnatal life increases the cholesterol content of the cerebrum in young adulthood following free access to a high-fat (15%), high-cholesterol (0.5%) diet from 8 to 20 or 24 wk of age. Pigs were removed from their dams at 1 d of age and given free access to a sow-milk replacer diet containing 9.5% coconut fat and 0 or 0.5 % cholesterol. All pigs (except four HG and four LG pigs in Experiment 2, which were deprived of cholesterol throughout the study) were fed the high-fat, high-cholesterol diet from 8 wk to termination at 20 or 24 wk of age. Cerebrum weight and cholesterol concentration were higher in pigs fed cholesterol neonatally than in those deprived of cholesterol neonatally in both experiments, but weight and cholesterol concentration were unaffected by genetic line. Cholesterol concentrations in longissimus and semitendinosus muscles and in subcutaneous fat were unaffected by diet or genetic line. We conclude that dietary cholesterol deprivation during the first 4 to 8 wk of life in piglets is associated with lower cholesterol concentration and total content in the young adult cerebrum than in pigs supplemented with cholesterol in early life. These data support previous observations and suggest the possibility of a metabolic need for neonatal dietary cholesterol in normal brain development.

National Beef Quality Audit-1995: survey of producer-related defects and carcass quality and quantity attributes.

The National Beef Quality Audit-1995 was conducted to evaluate the progress of the beef industry since the time of the National Beef Quality Audit-1991 in improving quality and consistency of beef. Nine plants were assigned for auditing to Colorado State University, Oklahoma State University, and Texas A&M University. Personnel from each institution visited three of their nine plants twice, once in the spring/summer and once in the fall/winter. Data were collected on 50% of each lot on the slaughter floor and 10% in the cooler during a single day's production (one or two shifts, as appropriate). Of the cattle audited on the slaughter floor, 47.7% had no brands, 3.0% had a shoulder brand, 16.8% had a side brand, 38.7% had a butt brand, and 6.2% had brands in multiple locations. Data revealed that 51.6% of the carcasses had no bruises, 30.9% had one bruise, 12.8% had two bruises, 3.7% had three bruises, .9% had four bruises, and .1% had more than four bruises. In addition, 7.2% of the bruises evaluated were located on the round, 41.1% were on the loin, 20.8% on the rib, and 30.8% on the chuck. Livers, lungs, tripe, heads, tongues, and whole carcasses were condemned at rates of 22.2, 5.0, 11.0, .9, 3.8, and .1%, respectively. Mean USDA yield grade and quality grade traits were as follows: USDA yield grade, 2.8; carcass weight, 338.4 kg; adjusted fat thickness, 1.2 cm; longissimus muscle area, 81.9 cm2; kidney, pelvic, and heart fat, 2.1%; USDA quality grade, High Select; overall maturity, A60; and marbling score, Small-minus.

Consumer evaluation of beef of known categories of tenderness.

A study was conducted to determine consumer perceptions of beef top loin steaks of known shear force and to evaluate how buying trends were modified by the tenderness and price variations of these steaks. Strip loins were cut into a 2.54-cm-thick steaks, and the center steak from each strip loin was used to determine Warner-Bratzler shear force. The remaining steaks were placed into one of the following shear force categories based on that shear force and color-coded accordingly: 1) 2.27 to 3.58 kg (Red); 2) 4.08 to 5.40 kg (White); and 3) 5.90 to 7.21 kg (Blue). Randomly recruited consumers were allowed to evaluate steaks and then purchase steaks based on their findings. A $1.10/kg price difference was placed between each category. Results of the analysis indicated that consumers were able to differentiate between the three categories of tenderness (P < .05). In addition, consumers gave higher (P < .05) juiciness and flavor ratings to Red steaks than to Blue steaks. Overall satisfaction was higher (P < .05) for Red steaks than for the other two categories of steaks. The following percentages of steaks were purchased: 1) Red, 94.6%; 2) White, 3.6%; and 3) Blue, 1.8%. These results suggest that consumers could discern between categories of tenderness and were willing to pay a premium for improved tenderness.

Effect of chromium picolinate on growth, body composition, and tissue accretion in pigs.

An experiment was conducted to evaluate the effect of dietary chromium picolinate (CrP) on growth and body composition of pigs. Twenty-four barrows (three from each of eight litters) were randomly allotted within litter to one of three treatments: 1) basal (B) diet from 19.1 to 106.4 kg BW (Control); 2) B from 19.1 to 57.2 kg BW and then B + 200 ppb of chromium as CrP from 57.2 to 106.4 kg BW (CrP-F); and 3) B + 200 ppb of chromium as CrP from 19.1 to 106.4 kg BW (CrP- GF). Average daily gain and ADFI were reduced (P < .08) and first rib fat thickness was increased (P < .08) in pigs fed CrP-GF compared with pigs fed the Control diet. Specific gravity of the carcass was not affected (P > .10) by treatment. Tenth rib fat was reduced (P < .01) in pigs fed CrP-F compared with pigs fed CrP-GF, and percentage of muscle was increased in pigs fed CrP-F (P < .09) compared with pigs fed either the Control or CrP-GF diets. Leaf fat (P < .05) and lung weights (P < .08) were reduced in pigs fed CrP-F compared with pigs fed CrP-GF. As determined by physical-chemical separation, pigs fed CrP-GF had an increased (P < .07) percentage of intermuscular fat compared with pigs fed the Control or CrP-F diets. Pigs fed CrP-F had a lesser (P < .07) percentage of total fat and a greater (P < .07) percentage of muscle than pigs fed the Control or CrP-GF diets. As determined by mechanical-chemical separation, pigs fed CrP-F had a greater (P < .10) percentage of moisture than pigs fed the Control diet and a lesser (P < .10) percentage of fat and a greater (P < .06) percentage of ash than pigs fed the Control or CrP-GF diets. Pigs fed CrP-GF had an increased (P < .04) daily fat accretion compared with pigs fed CrP-F. Sensory and shear force values were not affected by CrP, with the exception that meat from pigs fed CrP-GF had a greater (P < .10) shear force value than meat from pigs fed CrP-F. These results suggest that dietary supplementation of CrP in the finishing phase of pig production may increase muscle and decrease fat deposition; however, not all measures of muscling or fatness were improved by CrP.

Effects of Postmortem time of calcium chloride injection on beef tenderness and drip, cooking, and total loss.

The effect of postmortem time of calcium chloride (CaCl(2)) injection in conjunction with postmortem aging was determined on 16 beef semimembranosus muscles. Each muscle was cut into four equal segments that were randomly assigned: (1) no injection (control); (2) CaCl(2) at 1 h postmortem; (3) CaCl(2) at 12 h postmortem; or (4) CaCl(2) at 24 h postmortem. Samples were injected with a 0·3 m solution of CaCl(2) at 10% by weight. At 24 h postmortem, each segment was divided into two pieces that were randomly assigned to either a 10-day aging period (2°C) or to frozen storage (-29°C). Shear force values were higher (P < 0·01) in control samples compared with injected samples and increased linearly (P < 0·05) with time of injection. Drip loss was lower (P < 0·01) in control samples compared with injected samples. A linear (P < 0·05) effect was found for the increases in cooking and total loss due to injection time. Aging decreased (P < 0·05) shear force values and cooking loss. CaCl(2) injection at 1 h postmortem was most effective in reducing shear force values and preventing excessive moisture loss. However, injection at 12 or 24 h postmortem was also effective in lowering shear force values.