Allocating forage to fall-calving cow-calf pairs strip-grazing stockpiled tall fescue.

In a 2-yr study, we evaluated the effect of different forage allocations on the performance of lactating beef cows and their calves grazing stockpiled tall fescue. Allocations of stockpiled tall fescue at 2.25, 3.00, 3.75, and 4.50% of cow-calf pair BW/d were set as experimental treatments. Conventional hay-feeding was also evaluated as a comparison to grazing stockpiled tall fescue. The experiment had a randomized complete block design with 3 replications and was divided into 3 phases each year. From early December to late February (phase 1) of each year, cows and calves grazed stockpiled tall fescue or were fed hay in the treatments described above. Immediately after phase 1, cows and calves were commingled and managed as a single group until weaning in April (phase 2) so that residual effects could be documented. Residual effects on cows were measured after the calves were weaned in April until mid-July (phase 3). During phase 1 of both years, apparent DMI of cow-calf pairs allocated stockpiled tall fescue at 4.50% of BW/d was 31% greater (P < 0.01) than those allocated 2.25% of BW/d. As allocation of stockpiled tall fescue increased from 2.25 to 4.50% of cow-calf BW/d, pasture utilization fell (P < 0.01) from 84 +/- 7% to 59 +/- 7%. During phase 1 of both years, cow BW losses increased linearly (P < 0.02) as forage allocations decreased, although the losses in yr 1 were almost double (P < 0.01) those in yr 2. During phases 2 and 3, few differences were noted across treatment groups, such that by the end of phase 3, cow BW in all treatments did not differ either year (P > 0.40). Calf ADG in phase 1 increased linearly (P < 0.01) with forage allocation (y = 0.063x + 0.513; R(2) = 0.91). However, calf gain per hectare decreased linearly (P < 0.01) as stockpiled tall fescue allocations increased (y = -26.5x + 212; R(2) = 0.97) such that gain per hectare for cow-calf pairs allocated stockpiled tall fescue at 4.50% BW/d was nearly 40% less (P < 0.01) than for those allocated 2.25% of BW/d. Allocating cow-calf pairs stockpiled tall fescue at 2.25% of BW/d likely optimizes its use; because cow body condition is easily regained in the subsequent spring and summer months, less forage is used during winter, and calf gain per hectare is maximized.

Endophyte infection level of tall fescue stockpiled for winter grazing does not alter the gain of calves nursing lactating beef cows.

We examined the effect of endophyte infection level of tall fescue (Festuca arundinacea Schreb.) used for stockpiled forage on the performance of lactating, fallscalving beef cows and their calves. Treatments were endophyte infection levels of 20% (low; SEM = 3.5), 51%, (medium; SEM = 1.25), and 89% (high; SEM = 2.4; 4 replications/treatment). Five cow-calf pairs grazed in each replicate (n = 60 cow-calf pairs/yr) for 84 d (phase 1) starting on December 2, 2004 (yr 1), and December 1, 2005 (yr 2). After 84 d of grazing each treatment, the cattle were commingled and fed as a single group (phase 2) until weaning in April of each year. Phase 2 allowed measurement of residual effects from grazing stockpiled tall fescue with varying levels of endophyte infection. Pregrazing and postgrazing forage DM yield, forage nutritive value, and total ergot alkaloid concentrations of forage were collected every 21 d during phase 1. Animal performance data included cow BW, ADG, and BCS, as well as calf BW and ADG. Animal performance was monitored during both phases. Endophyte infection did not affect (P = 0.52) apparent intake (pregrazing minus postgrazing forage DM yield) of stockpiled tall fescue, because each cow-calf pair consumed 16 +/- 1.7 kg/d regardless of treatment. Cow ADG during phase 1 was -0.47 +/-0.43 kg for the low treatment, which was greater (P < 0.01) than either the medium (-0.64 +/-0.43 kg) or high (-0.74 +/- 0.43 kg) treatments. However, cows that had grazed the high or medium treatments in phase 1 lost -0.43 and -0.57 (+/-0.24) kg/d, respectively, which was less (P < 0.01) BW loss than the cows in the low (-0.78 +/- 0.24 kg/d) treatment during phase 2. By the end of phase 2, cow BW did not differ (528 +/-27 kg; P = 0.15). Body condition score for cows in the low treatment was greater (P = 0.02) than that of the medium and high treatments at the end of phase 1. Body condition scores did not change appreciably by the end of phase 2, and differences among treatments remained the same as at the end of phase 1 (P = 0.02). In contrast to cow performance, calf ADG was unaffected (P = 0.10) by endophyte level and averaged 0.73 +/- 0.07 kg during phase 1 and 0.44 +/- 0.04 kg during phase 2. Our data suggest that fall-calving herds can utilize highly-infected tall fescue when stockpiled for winter grazing, with little impact on cow performance and no impact on calf gain.

Growth and reproduction in captive tufted capuchins (Cebus apella).

We present data on weight and reproduction from a colony of tufted capuchins monkeys (Cebus apella) over a 12 year period. The data constitute a normative record for this species. Weight at birth averages 210 g, and infants gain weight rapidly. Females typically first conceived just after their fifth birthday, and males were fertile by 4 years, 5 months. Interbirth intervals average 576 days. Eighty-seven percent of live-born infants survived past 6 months. Three of eight live-born infants that died prior to 6 months succumbed from trauma inflicted by cage mates.

Developmental changes in manipulation in tufted capuchins (Cebus apella) from birth through 2 years and their relation to foraging and weaning.

This study examined the contributions of physical and sensorimotor development to manipulation in capuchins (Cebus apella) from birth to 2 years. Between months 1-6 and 7-12, manipulation increased significantly in frequency, in the proportion that was vigorous or required fine motor control, and in the proportion directed at portable objects. Fine motor control, moving objects in relation to the body, and stamina are largely in place by 12 months, after which little changed. All elements of the manipulative repertoire have appeared, and vigorous and dexterous activities have peaked before fully independent foraging. Emergence of permanent dentition and achievement of approximately half of adult body size accompany the attainment of fully independent foraging at 15 months. Thereafter, increasing strength and specific knowledge probably contribute more to changing foraging competence in young capuchins than do stamina and sensorimotor development.

Neurochemical correlates of antiepileptic drugs in the genetically epilepsy-prone rat (GEPR).

The GEPR model is composed of two independently derived strains of rats each characterized by a broad-based seizure predisposition. Moderate seizure GEPRs (GEPR-3s) exhibit generalized clonus with loss of righting reflex in response to a standardized sound stimulus. The same stimulus in severe seizure GEPRs (GEPR-9s) produces a tonic-clonic convulsion much like that produced by supramaximal electroshock. The numeric descriptors (3 and 9) derive from the ordinal rating scale developed by Jobe and coworkers for evaluation of convulsion intensity. GEPRs experience an anticonvulsant effect in response to all established and many experimental antiepileptic drugs and distinctions between the classes of drugs can be made. Since serotonin plays an anticonvulsant role in nearly all animal seizure models, we examined the effects of antiepileptic drugs on serotonin using microdialysis. Among clinically effective anticonvulsants, carbamazepine, antiepilepsirine (used in China) and loreclezole produced dose-related anticonvulsant effects and increases in extracellular serotonin in GEPRs. Similarly, drugs known to block serotonin reuptake and increase extracellular serotonin (fluoxetine and sertraline) produce dose related anticonvulsant effects in GEPRs and other animal models. Accentuation of serotonin release by treating GEPRs with fluoxetine and 5-hydroxytryptophan enhances the anticonvulsant effect produced by fluoxetine. Depletion of serotonin greatly decreased the anticonvulsant effect produced by carbamazepine, antiepilepsirine and fluoxetine. Phenytoin produced a dose related anticonvulsant effect in GEPRs but did not increase extracellular serotonin. Depletion of serotonin did not diminish the anticonvulsant effect produced by phenytoin. Thus, serotonin appears to play a role in the anticonvulsant effect of several but not all anticonvulsant drugs.

Anticonvulsant properties of D-20443 in genetically epilepsy-prone rats: prediction of clinical response.

D-20443 is an experimental antiepileptic drug. Its mechanism of antiepileptic action is unknown. We evaluated the anticonvulsant effectiveness of D-20443 against sound-induced seizures in genetically epilepsy-prone rats (GEPRs). This compound produced anticonvulsant effects against sound-induced seizures in moderate seizure GEPRs (GEPR-3s) at significantly lower doses than in severe seizure GEPRs (GEPR-9s). Based on these data and on the responses of GEPRs to other antiepileptic drugs, we predict that D-20443 will be a broad spectrum antiepileptic agent in humans. That is, we predict that D-20443 will suppress both tonic/clonic and absence seizures in humans.

The genetically epilepsy-prone rat (GEPR).

Two independently inbred strains of genetically epilepsy-prone rats (GEPRs) have been developed. GEPR-3s and GEPR-9s have moderate and severe degrees of seizure predisposition as well as expression, respectively. Seizure predisposition is a fundamental distinction between the normal and epileptic brain. Seizure predisposition in GEPRs and in humans with epilepsy includes spontaneous seizures and exaggerated seizure responsiveness and/or abnormally low thresholds to stimuli which also cause seizures in non-epileptic subjects. Activation of brainstem seizure circuitry by auditory input via the inferior colliculus causes electrographic and behavioral responses in GEPR-9s which replicates human generalized tonic/clonic seizures. Activation of brainstem seizure circuitry by input from forebrain seizure circuitry in GEPRs provides a newly discovered model of complex partial seizures with secondary generalization to tonic/clonic seizures. Thus, seizure predisposition in GEPRs offers a unique opportunity to study the human epilepsies that is not offered in studies of normal brain exposed to convulsant stimuli.

The essential role of integrative biomedical sciences in protecting and contributing to the health and well-being of our nation.

The biomedical sciences in the United States are currently experiencing the effects of an increased emphasis on in vitro models of biological and disease processes. Advances in cellular and subcellular biology have been a driving force in the funding of new research, the training of new scientists, and new drug discovery and development. The importance of new findings at the cellular and subcellular levels is not disputed. However, the corresponding decline in funding and training opportunities for biologically relevant investigations at the level of the intact animal (including humans; hereafter designated as integrative biology) is a serious threat to continued biomedical advances. The lack of resources for integrative biology has far-reaching negative consequences in 1) the development and utilization of whole animal models of disease and dysfunction; 2) assessing the relevancy of in vitro studies to physiological mechanisms; 3) the evaluation of the scientific merit of whole animal investigations and their relevancy to the nation's scientific imperatives; 4) the instruction of young scientists in the technology and especially in the methods of integrative biology, including how to develop appropriate experimental hypotheses; 5) the instruction of graduate, medical, dental, pharmacy, and nursing students in drug and disease processes in the intact human; and 6) the ability of the pharmaceutical manufacturers, the FDA, the EPA and academia to hire scientists who can develop drugs and evaluate the effects of exogenous agents on the intact animal. These negative consequences can be alleviated in a variety of ways. These include 1) increasing the availability of funding for research in integrative biology, 2) increasing the opportunities for training in integrative biology, and 3) instituting grant reviews of integrative biomedical research by peers in integrative biomedical sciences. These measures can revitalize integrative biomedical research, help ensure the continued advancement of biomedical understanding, and consequently contribute to the alleviation of human suffering.

Development of manipulation in capuchin monkeys during the first 6 months.

This study describes the orderly changes in manipulation over the first 6 months in capuchin monkeys (Cebus apella). By 6 months of age, all the basic forms of manipulation seen in adults have appeared. Actions that occur frequently in the first 8 weeks are gentle and involve sustained visual orientation and aimed reaching. Later actions are more vigorous, and involve grasping. Large increases in the rate of activity are evident over the period of development studied. The increase from the first 8 weeks to the second may be due to (a) an increase in the amount of time spent alert and active, (b) a decrease in the amount of time spent in a ventral position, (c) improvements in postural control and stamina and (d) the onset of independent locomotion. Changes in form can be attributed primarily to postural factors and to neuromuscular development (precisely aimed and controlled movements appearing in the 5th and 6th months).

Noradrenergic abnormalities in the genetically epilepsy-prone rat.

The genetically epilepsy-prone rat (GEPR) has central nervous system noradrenergic deficits as compared to normal rats. It is possible that these deficits contribute to seizure predisposition because they are exhibited by seizure-naive as well as by seizure-experienced GEPRs. On the basis of pharmacological studies, it is hypothesized that there is an inverse relation between seizure predisposition and levels of noradrenergic activity in brain. Neurochemical studies indicate that deficits exist in areas innervated by both the locus ceruleus and the lateral tegmental noradrenergic systems. These deficits exist in GEPRs without seizure experience and are more pronounced in the severe seizure strain as compared to the moderate seizure strain. We review eight experimental steps undertaken to identify more precisely the anatomical location of noradrenergic determinants of seizure predisposition. These steps illustrate the theoretical bases for the studies and describe the specific experiments completed. Evidence supports the hypothesis that noradrenergic deficits in the superior colliculus and/or ventrally adjacent regions are determinants of seizure predisposition.

Generative aspects of manipulation in tufted capuchin monkeys (Cebus apella).

Evaluating the cognitive and ontogenetic bases of tool use in primates requires comparative data on the generative nature of manipulation, including the frequency and variety of combinations of actions and objects. Thirty-one tufted capuchins (Cebus apella) of 3 age groups devoted significant proportions of time to interaction with objects and substrates. Activity that combined an object with a substrate occurred often; activities that combined 2 portable objects were less frequent. Predictions drawn from neo-Piagetian theory of an ontogenetic link between combinatorial behaviors and the onset of tool use were not supported. The frequency and generative nature of capuchins' manipulative activity, particularly acts combining objects and substrates, could account for their proclivity to use tools. The use of tools by capuchins need not involve the representational abilities proposed by neo-Piagetian theory.

Conceptual learning in capuchin monkeys.

This paper reviews concept learning in Cebus monkeys, focussing on their ability to use the identity relation, oddity and natural concepts. Capuchins are similar to other primate genera in their use of these concepts. The extant data on learning in primates generally reflect historical concerns with general processes of learning. An alternative approach which considers the tasks the animal faces in its natural environment may be better suited to the discovery of species-unique characteristics of learning. This approach has not yet been applied to Cebus.

Antibiotic prophylaxis in high-risk biliary operations: multicenter trial of single preoperative ceftriaxone versus multidose cefazolin.

A prospective, double-blind trial of a single preoperative dose of ceftriaxone, a new long-acting cephalosporin, versus one preoperative and three postoperative doses of cefazolin was carried out in 81 patients at high risk of infection after biliary surgery. Indications for antibiotic prophylaxis included recent or ongoing cholecystitis (52 patients), common duct stones (14 patients), common duct obstruction (3 patients), and age greater than 70 years (22 patients). Intraoperative bile cultures were positive in 7 of 41 patients (17.1 percent) given ceftriaxone and 12 of 40 patients (30 percent) given cefazolin, but there were no wound infections in either group. Neither regimen was associated with significant antibiotic resistance. Side effects, such as proteinuria and elevated liver transaminases and alkaline phosphatase levels, were transient and not definitely related to the antibiotics. We conclude that a single preoperative dose of ceftriaxone is as effective as multiple perioperative doses of cefazolin in the prophylaxis of infection associated with biliary tract surgery.

Infant perception of numerosity.

A multiple habituation paradigm was used to determine whether 10--12-month-old infants were able to discriminate between visual arrays which differed only in their numerosity (2 vs. 3, 3, vs. 4, or 4 vs. 5 items). 96 infants were tested in one of two conditions. In the heterogeneous condition, infants were habituated to a series of slides in which only the number of items remained invariant, while the item type (e.g., dogs, houses, etc.), size, and position varied on each slide. In the homogeneous condition, both the item type (chicks) and number remained invariant, while the size and position of the stimuli varied. Infants in both conditions were then tested with slides which contained either N + 1 or N - 1 items. The results demonstrated that, regardless of condition (homogeneous/heterogeneous), infants were able to discriminate between 2 and 3 items and unable to discriminate between 4 and 5 items. For the 3 versus 4 discrimination, a condition x sex interaction indicated that females discriminated between the items in the homogeneous condition while males were able to make the discrimination in the heterogeneous condition. Since the subjects in this study were preverbal infants, the results suggest that early counting skills are preceded by a more perceptual awareness of numerosity.