New allelic fragment for the growth hormone-TaqI marker in cattle.
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Alleles↗
Biomedical subjects
J F Baker
Publications and source records attributed to J F Baker.
New allelic fragments for parathyroid hormone-MspI in cattle.
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Alleles↗
Statistical associations between restriction fragment length polymorphisms and quantitative traits in beef cattle.
Data on 41 traits from 677 animals produced in a five-breed diallel were matched with genotypes for five marker-loci provided by restriction fragment length polymorphisms to detect quantitative effects associated with the markers, following three different designs based on inbred lines, half-sib families, and on assumptions of the markers being quantitative trait loci (QTL). Three growth hormone-TaqI alleles, B, C, and D, in high frequencies in this sample of the Brahman breed, were associated with decreases in birth weight, as a maternal trait (P < .01), and decreases in shoulder width at birth (P < .05). Among F2 Angus-Brahman and Brahman-Hereford cows, homozygotes for the B, C, or D alleles gave birth to calves 4.0 kg lighter than cows homozygous for the A allele, an effect that amounts to the magnitude of the corresponding breed difference in the diallel, and represents one phenotypic SD. A putative cytoplasmic effect seems to interact (P = .02) with this effect on maternal birth weight. Also, at birth, F2 calves homozygous for the B, C, or D alleles were .8 cm narrower at the shoulders than those homozygous for the A allele, after adjusting for birth weight. Significant associations (P < .05) between the parathyroid hormone-MspI marker and measures of body size were detected, as well as an effect on weaning weight (P = .03) as a maternal trait, whose magnitude (17.5 kg) equals the Brahman vs Angus and Hereford breed difference, as quantified in the diallel, and represents .8 of a phenotypic SD. No significant associations were found for three other marker-loci (prolactin-MspI, osteonectin-EcoRI, and keratin VI-MspI). Restriction fragment length polymorphisms have the potential to provide new insights and useful applications to animal breeding, but, as in this work, small sample sizes, extreme susceptibility to Type I errors, and different types of possible confounding obfuscate the conclusions that can be drawn from studies of limited scope and less than ideal planning.
Alleles↗
Forage availability x heifer phenotype interactions for Brahman-Hereford F1 yearling heifers grazing humid pasture and semiarid rangeland.
Yearling heifer growth data were obtained during 4 yr for 524 heifers allotted to either humid bermuda grass pastures (Overton) or semiarid rangeland (Uvalde). Each year, heifers were allotted on April 15 to four forage availability levels (400 to 2,800 kg of DM per 100 kg of BW at Uvalde and 80 to 260 kg of DM per 100 kg of BW at Overton) maintained by varying the stocking rate monthly until mid-October of each year. Forage availability and yearling heifer characteristics (weight, condition score, and height at hooks, taken on April 15) were treated as continuous variables in regression analyses. Final heifer weight, height, and condition responses to increased forage allowance were related to yearling phenotypes differently for the two locations. Generally, at Overton, forage availability influenced final characteristics to a greater extent than did yearling variables, whereas the trend was the opposite at Uvalde. At Uvalde, the yearling characteristic that had the largest effect on performance was height at hooks. Yearlings with large frames benefited from increased forage allowance by accumulating body fat at a faster rate than those with small frames. In contrast, at Overton, the yearling characteristic that had the largest effect on performance was condition. Fat heifers responded to increased forage availability to gain even greater advantages in fatness at the expense of potential growth in height and, thus, achieved early maturation. Yearling phenotypes were more broadly adapted to arrays of forage availability for humid, improved pastures than for semiarid rangeland.
Adipose Tissue↗
Frequency dependence of cat vestibulo-ocular reflex direction adaptation: single frequency and multifrequency rotations.
Vertical and horizontal vestibulo-ocular reflex (VOR) eye movements were recorded in alert cats during horizontal rotation in total darkness before and after a 2 h vestibulo-ocular reflex direction adaptation procedure. Adaptation stimuli were whole body horizontal vestibular rotation coupled to synchronous vertical optokinetic motion. The waveform of the adaptation stimuli was either a sinusoid at 0.05, 0.1, 0.25, 0.5, or 1 Hz, or a sum of sinusoids containing 0.2, 0.3, 0.5, 0.7, 1.1, and 1.7 Hz. Exposure to single frequency stimuli produced adaptive vertical VOR with a gain that was greatest near the training frequency; adaptive VOR phases were advanced below, accurate at, and lagged above the training frequency. Exposure to the multifrequency waveform produced a uniform modest increase in gain across frequencies, with accurate adaptive VOR phase.
Acclimatization↗
Torque vectors of neck muscles in the cat.
Anatomical texts describe the neck musculature without measurements of muscle locations or quantitative estimates of pulling actions (torques). This study is based on measurements in stereotaxic coordinates of cat neck muscle origins and insertions, and neck intervertebral rotation axes. Torque vectors in three dimensions were calculated for 14 pairs of dorsal and ventral muscles that insert on the skull or first cervical vertebra. Predicted torque vectors were in general agreement with qualitative statements in the literature. Biventer cervicis and the rectus capitis major, medius, and minor muscles act mainly to raise the head, and longus capitis acts almost exclusively to lower the head. Longissimus capitis, sternomastoid, and cleidomastoid act mainly to roll the head. Complexus acts about equally to raise the head and rool it. Splenius and occipitoscapularis have torque in all three coordinate directions. Torques were altered by changing the pitch of the head with respect to the neck. The calculated neck muscle torques did not correspond to previously reported directions of neck muscle excitation during the vestibulocollic reflex. The neck musculature appears to be a complex, multidimensional system that presents interesting problems in motor control.
Animals↗
Excitation of the extraocular muscles in decerebrate cats during the vestibulo-ocular reflex in three-dimensional space.
(1) Vestibulo-ocular reflex excitation of the six extraocular muscles was studied by recording their electromyographic activity in decerebrate cats during oscillations about horizontal and vertical axes, at frequencies from 0.07 to 4 Hz. Animals were oriented in many different positions and rotated about axes that lay in the horizontal, frontal, or sagittal planes defined by our coordinate system. (2) The strengths of modulation (gains) of the responses of all extraocular muscles were a sinusoidal function of the orientation of the rotation axis within a coordinate plane, and this function was nearly independent of rotation frequency. (3) The responses were used to determine an axis of maximal excitation for each of the extraocular muscles by the vestibulo-ocular reflex. Antagonistic muscle pairs were found to have best axes in nearly opposite directions, confirming their operation as pairs. (4) Excitation of the medial and lateral rectus could be explained by input from the paired horizontal semicircular canals, with essentially no convergent input from vertical canals. (5) Excitation of the vertical rectus and oblique muscles could be explained by convergent inputs from the vertical canals with little or no horizontal canal input.
Animals↗
A model of adaptive control of vestibuloocular reflex based on properties of cross-axis adaptation.
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Adaptation, Physiological↗
Role of solid media when used in conjunction with the BACTEC system for mycobacterial isolation and identification.
This study evaluated the necessity and the contribution of solid media when used in conjunction with radiometric Middlebrook 7H12 (BACTEC 12B; Becton Dickinson, Towson, Md.) medium for recovery and complete identification of mycobacteria. Each of 1,184 digested, decontaminated respiratory specimens was inoculated into one BACTEC 12B vial, one 7H11 plate, and two Lowenstein-Jensen (LJ) slants. When the 12B vial was smear positive for acid-fast bacilli, the organisms were subcultured onto LJ slants and the BACTEC p-nitro-alpha-acetylamino-beta-hydroxypropiophenone (NAP) test system was inoculated with the organisms. Niacin tests were performed by using the growth from the original LJ slants and organisms from the LJ slants subcultured from 12B or 7H11 medium. The times to achieve definitive NAP and niacin test results were recorded. Recovery of all 143 isolates found in this study could not be achieved with a single medium. Among the three media, the highest percentage (92.8%) of Mycobacterium tuberculosis isolate recovered was with BACTEC 12B. The use of either 7H11 medium or LJ slants along with a 12B vial increased by 4 to 6% the total percentage of M. tuberculosis organisms that were isolated. Isolation of the M. tuberculosis complex and NAP differentiation in 12B medium were completed in an average of 17 days. On average, isolation and definitive niacin test results for M. tuberculosis cultures were obtained in 39.3 days by a conventional procedure and in 36.3 days when 12B subcultures were used. These results support the conclusion that LJ slants contribute 4 to 6% increased recovery of M. tuberculosis when used in conjunction with 12B medium. Additionally, a subculture onto LJ slants from 12B medium yielded sufficient growth for niacin testing earlier than an original LJ slant did.
Bacteriological Techniques↗
Body composition and fasting heat production from birth to 14 months of age for three biological types of beef heifers.
Thirty heifers were randomly sampled at five ages from each of the Hereford, Charolais, and Simmental herds at the U.S. Meat Animal Research Center to estimate association of fasting heat production (FHP) with body composition. Replicated measures of respiratory exchange were obtained for six heifers per breed at ages 2 d, 3 mo, 7 mo, 10 mo, and 14 mo using open-circuit calorimetry. Regression adjustment of FHP/live weight.75 to zero activity (AFHP) reduced the mean by 12% and variance among periods for the same animal by 42%. Daily AFHP (kcal/kg.75) was highest at 2 d (122), lowest at 10 mo (92) (P less than .01), and intermediate (103 to 106) at other ages and averaged 109, 106, and 102 for Charolais, Simmental and Hereford over all ages (P less than .05). Pooled within-age correlations of AFHP were .77 with weight of carcass (CAR) nonfat or water and .75 with live and empty body weight (EBW) but were only .13 with fat weight. Prediction of AFHP within age groups was most accurate from multiple regression on the nonfat weight in visceral organs and blood (VOB), gastrointestinal tract (GIF), head, hide, and shanks (HHS), and CAR fractions (R2 = 61%, error SD = 21.5), from regression on nonfat in CAR alone (60%, 21.6), or from regression on chemical components in each of the four fractions (59%, 22.0), relative to EBW (55%, 22.9) or its four chemical components (58%, 22.3). Partial regressions were largest for water or nonfat (P less than .01) and were negligible for fat. Importance in predicting AFHP was two to eight times greater for nonfat in CAR than in other fractions because CAR was 60 to 65% of EBW. Lean mass is clearly a major predictor of nutrient requirement that is useful to evaluate effects of body composition on the efficiency of beef production.
Adipose Tissue↗
Heterosis retention for birth and weaning characters of calves in the third generation of a five-breed diallel.
Data were 876 birth records and 727 weaning records of straightbred and F3 crossbred calves produced in the third generation of a five-breed diallel. Among straightbreds at birth, Holstein calves were heaviest and widest at the shoulders and hips. Jersey calves were lightest and narrowest at the hips, and Brahman calves were narrowest at the shoulders. Holstein crosses tended to be larger at birth than crosses among other breeds. Among straightbreds at weaning, Holstein calves were heaviest and tallest, and Hereford calves were lightest and shortest. Angus calves had the highest survival to weaning rate, and Holstein calves had the lowest survival rate. Among crossbred calves, Holstein crosses tended to be larger at weaning. Estimates of average heterosis retained for birth characters were not significant. Significant breed mean heterosis retention was observed for birth weight, shoulder width, and hip width of Hereford calves and for shoulder width and hip width of Holstein calves. Estimates of average heterosis retained for weaning weight and height were 6.1 kg (P less than .01) and 1.02 cm (P less than .05), respectively. In general, estimates of specific and average heterosis retained for survival to weaning were nonsignificant. Significant breed mean heterosis was observed for weaning weight and height of Brahman, Hereford, and Holstein calves and for survival to weaning of Hereford, Holstein, and Jersey calves.
Animals↗
Characterization of relative growth of empty body and carcass components for bulls from a five-breed diallel.
Slaughter and carcass data were obtained on 197 bulls produced in a diallel involving Angus, Brahman, Hereford, Holstein and Jersey that were slaughtered at either 6, 9, 12, 15, 18, 24, or 30 mo of age. Bulls were given ad libitum access to a 72% TDN diet on an individual basis from 6 mo of age until slaughter. Empty body weight (EBWT) was determined as the sum of the weights of blood, hide, hard drop, soft drop (minus contents of the digestive tract), and carcass weight (CWT), which were recorded at slaughter. Carcass protein (CPROT) and fat (CFAT) were based on weights and chemical analyses of lean and fat tissue and bone of the carcass. Empty body protein (EBPROT) and fat (EBFAT) were based on weights and chemical estimates of the components of the empty body. Growth of EBWT, EBPROT, EBFAT, CWT, CPROT, and CFAT relative to either live weight (LWT), EBWT, or CWT were investigated using the allometric equation. Breed-type differences existed (P less than .01) for the growth of EBWT relative to LWT. Comparisons of general combining abilities revealed that Angus, Hereford, and Jersey generally had lower maturing rates of EBWT relative to LWT and that Brahman and Holstein had higher maturing rates. Across breed-type, relative growth rates indicated that fat and protein were later-maturing components relative to LWT, EBWT, or CWT, which implies that other components mature relatively earlier. Relative maturing rates of components studied were not important in explaining differences in body composition that have been previously reported for these breed-types.
Adipose Tissue↗
Spatial properties of second-order vestibulo-ocular relay neurons in the alert cat.
Second-order vestibular nucleus neurons which were antidromically activated from the region of the oculomotor nucleus (second-order vestibuloocular relay neurons) were studied in alert cats during whole-body rotations in many horizontal and vertical planes. Sinusoidal rotation elicited sinusoidal modulation of firing rates except during rotation in a clearly defined null plane. Response gain (spike/s/deg/s) varied as a cosine function of the orientation of the cat with respect to a horizontal rotation axis, and phases were near that of head velocity, suggesting linear summation of canal inputs. A maximum activation direction (MAD) was calculated for each cell to represent the axis of rotation in three-dimensional space for which the cell responded maximally. Second-order vestibuloocular neurons divided into 3 non-overlapping populations of MADs, indicating primary canal input from either anterior, posterior or horizontal semicircular canal (AC, PC, HC cells). 80/84 neurons received primary canal input from ipsilateral vertical canals. Of these, at least 6 received input from more than one vertical canal, suggested by MAD azimuths which were sufficiently misaligned with their primary canal. In addition, 21/80 received convergent input from a horizontal canal, with about equal number of type I and type II yaw responses. 4/84 neurons were HC cells; all of them received convergent input from at least one vertical canal. Activity of many vertical second-order vestibuloocular neurons was also related to vertical and/or horizontal eye position. All AC and PC cells that had vertical eye position sensitivity had upward and downward on-directions, respectively. A number of PC cells had MADs centered around the MAD of the superior oblique muscle, and 2/3 AC cells recorded in the superior vestibular nucleus had MADs near that of the inferior oblique. Thus, signals with spatial properties appropriate to activate oblique eye muscles are present at the second-order vestibular neuron level. In contrast, none of the second-order vestibuloocular neurons had MADs near those of the superior or inferior rectus muscles. Signals appropriate to activate these eye muscles might be produced by combining signals from ipsilateral and contralateral AC neurons (for superior rectus) or PC neurons (for inferior rectus). Alternatively, less direct pathways such as those involving third or higher order vestibular or interstitial nucleus of Cajal neurons might play a crucial role in the spatial transformations between semicircular canals and vertical rectus eye muscles.
Animals↗
Measurements at calving for straightbred and crossbred cows of diverse types.
Reproductive and calving records of 611 cows from F1 and F2 generations from a diallel mating system with Angus, Brahman, Hereford, Holstein and Jersey were examined. The inter se matings were by artificial insemination, and each cow had three or four parturitions. Dependent variables included weight, hip weight at first calving, age at first calving, gestation length and calving interval. Brahmans were the heaviest, tallest and oldest purebred at first calving. Crossbred Brahman females tended to be older than other crosses at first calving. Purebred Brahmans and one-half Brahman crosses also had the longest gestation lengths and calving intervals. First-gestation (F1) crossbred cows were 18 kg heavier (P less than .05), 2.0 cm taller (P less than .01) and 35 d younger (P less than .05) at first calving than contemporary straightbreds. Average maternal heterosis for height at calving was significant (1.4 cm; P less than .05); however, estimates of specific and average maternal heterosis for measurements taken at first calving were generally nonsignificant. Estimates of specific and average individual and maternal heterosis were generally small and nonsignificant for gestation length and calving interval.
Age Factors↗
Body composition and tissue distribution from birth to 14 months for three biological types of beef heifers.
Thirty-four heifers were sampled randomly from each of the Hereford (He), Charolais (Ch) and Simmental (Si) herds at the U.S. Meat Animal Research Center at 2 d to 14 mo of age to examine body chemical composition and tissue distribution. Six heifers per breed were slaughtered after calorimetry at 2 d, 3 mo, 7 mo, 10 mo and 14 mo of age, and four others at 8 mo, to measure weight of empty body (EBW), water, fat, ash and protein as residual, in four fractions: carcass (CAR), head, hide and shanks (HHS), gastrointestinal tract plus internal fat (GIF) and visceral organs plus blood (VOB). Fasted live weight from birth to 14 mo increased from 39 to 414 kg for Ch, 38 to 385 kg for Si and 33 to 356 kg for He. Corresponding mean composition of EBW increased from 58 to 67% CAR and from 7 to 13% GIF but declined from 26 to 15% HHS and from 9 to 6% VOB. The water content of EBW declined from 73 to 51%, protein from 20 to 18% and ash from 4.3 to 3.5%, whereas fat increased from 3 to 28% and protein content of fat-free OM increased from 22% to 26%. Composition of CAR was similar to EBW but fat content increased more with age in GIF, less in HHS and least in VOB. Distribution of fat-free tissue changed from 58 to 66% in CAR, 26 to 18% in HHS, 7 to 8% in GIF and 9 to 8% in VOB. The EBW of Ch contained more CAR but less HHS than EBW of Si and HE. The EBW of Si and Ch contained more water and protein and less FAT than EBW of HE. The fatter He had proportionately less of their fat-free tissue in CAR (63%) and more in HHS (21%) and GIF (9%) than the Ch (66, 19, and 8%), with Si (64, 20 and 8%) intermediate. These age and breed differences in composition and tissue distribution may explain some of the variation in maintenance requirements.
Animals↗
Comparison of production characteristics from birth through slaughter of calves sired by Angus, Charolais or Piedmontese bulls.
Birth, weaning, growth and carcass records for calves sired by Angus, Charolais or Piedmontese bulls were used to evaluate the potential contribution of Piedmontese to beef production in the U.S. Bulls were mated by AI to Hereford and crossbred cows and heifers. Calves were born during fall 1985 or spring 1986. Statistical models used to analyze the importance of sire breed used sire nested within sire breed as a random effect. Effects of sex, birth season, contemporary group, dam breed and parity were considered fixed and tested with the residual error. Piedmontese-sired calves had the longest gestation length, followed by Charolais and Angus-sired calves (287.5, 285.0 and 282.8 d, respectively). Breed of sire was not significant for birth weight, but Piedmontese- and Charolais-sired calves had longer cannon bones than Angus-sired calves. Differences were found for weaning hip height, but weaning weights, weaning muscle scores and ADG during the preweaning period were similar for calves by the three sire breeds. When fed to a similar fat thickness, Angus-sired calves required fewer days on feed, produced lighter carcasses and gained less per day than Charolais- or Piedmontese-sired calves. Piedmontese-sired calves required more days on feed than Charolais-sired calves when slaughtered at a similar subcutaneous fat thickness. Piedmontese-sired calves produced carcasses with a larger average rib eye area, higher dressing percentage and lower (more desirable) yield grade than Charolais- or Angus-sired calves. No significant sire breed differences were detected for tissue cholesterol content.
Animals↗
Relationships of empty-body composition and fat distribution to live animal and carcass measurements in Bos indicus-Bos taurus crossbred cows.
Empty-body composition and fat distribution were determined for 55 nonpregnant, mature Bos indicus-Bos taurus crossbred cows fed to achieve variation in fatness. Prior to slaughter, cows were condition and frame scored, weighed and measured for hook height, hook width, heart girth and lengths from point of shoulder to pin and hook to pin. Fat thickness at three locations and ribeye area were measured ultrasonically on the live animal and carcass. Quality and yield grades were determined after a 48-h postslaughter chill. Visceral fat was excised at slaughter and weighed. Kidney, heart and pelvic (KHP) fat was excised from one side and the remainder of the side was separated into bone and soft tissue. Soft tissue was subsampled and analyzed for ether extract. Proportions of fat in soft tissue, bone, viscera and KHP were calculated. Variations of percentage of empty-body fat in soft tissue, KHP and bone were explained (R2 greater than .64) by equations involving either live animal or carcass measurements. Both ultrasonic and subjective fat estimates were of importance (P less than .05) in equations predicting fatness, indicating the importance of variation in fat distribution. Factor analysis indicated that fat accretion is a complex entity composed of several distinct distribution patterns (anterior-posterior, internal-external, intramuscular-intermuscular).
Adipose Tissue↗
Effects of optokinetic velocity and medial vestibulo-cerebellum lesions on vestibulo-ocular reflex direction adaptation in the cat.
Adaptive horizontal vestibulo-ocular reflex eye movements in response to vertical (pitch) rotations were produced by exposing three cats to synchronized horizontal optokinetic and vertical vestibular oscillations at 0.25 Hz. The effects of optokinetic stimulus velocity (6-80 degrees/s peak) and nodulo-uvular cerebellum lesions were studied. All optokinetic velocities elicited vestibulo-ocular reflex direction adaptation. though 6 degrees/s stimuli were somewhat less effective. Restricted aspirations of cerebellar vermis lobules IX and X in two cats resulted in reduced but still clearly evident adaptation.
Adaptation, Physiological↗