Airborne microbial flora in a cattle feedlot

A total of 1,408 cattle held in eight commercial feedlot pens were used to examine the quantity and diversity of microorganisms in cattle feedlot air. The effect of two feeding patterns on the generation of airborne dust and the total numbers of microorganisms was also examined (four feedlot pens/treatment). Microbial samples were collected, and dust particles that were 2.5 microm or less in diameter were measured with a Dustrak monitor during the evening dust peak for 4 days at sites both upwind and downwind of the feedlot pens. An Andersen biological cascade sampler was employed with different medium and incubation combinations for the capture and identification of bacteria and fungi. The results showed that when bacteria were considered, only nonpathogenic gram-positive organisms were recovered. However, gram-negative bacteria may have been present in a viable but nonculturable state. Fungi were recovered in smaller numbers than bacteria, and none of the fungi were pathogenic. The Dustrak results showed that one feeding pattern resulted in cattle behavior that generated levels of downwind dust lower (P = 0.04) than the levels generated by the behavior resulting from the other feeding pattern. However, the Andersen sampler results showed that there were no differences between feeding patterns with regard to the total number or diversity of microorganisms. The disparity may have been due to the different operating principles of the two systems. The overall numbers of microorganisms recovered were lower than those reported in studies of intensively housed farm animals in which similar recovery techniques were used.

A video data base system for studying animal behavior

Classification of farm animal behavior is based on oral or written descriptions of the activity in which the animal is engaged. The quantification of animal behavior for research requires that individuals recognize and code the behavior of the animal under study. The classification of these behaviors can be subjective and may differ among observers. Illustrated guides to animal behavior do not convey the motion associated with most behaviors. Video-based guides offer a method of quantifying behaviors with real-time demonstrations of the components that make up a behavior. An animal behavior encyclopedia has been developed to allow searching and viewing of defined (video-recorded) behaviors on the Internet. This video data base is being developed to initiate a system that automatically extracts animal motion information from an input animal activity video clip using a multiobject tracking and reasoning system. Eventually, the extracted information will be analyzed and described using standard animal behavior definitions (the behavior encyclopedia). The intended applications of the behavior encyclopedia and video tracking system are 1) an accessible data base for defining and illustrating behaviors for both research and teaching and 2) to further automate the collection of animal behavior data.

Effects of diverse developmental environments on neuronal morphology in domestic pigs (Sus scrofa)

Potential effects of environmental rearing conditions on the brains of farm animals have not been examined experimentally, with the exception of one report for pig somatosensory cortex. The goal of the present experiment was to determine whether different developmental environments in use in agricultural production units affect neuronal morphology in the pig cerebral cortex. Littermate female pigs (gilts) were cross-fostered at birth and reared in either an indoor (n = 6) or outdoor (n = 6) production unit for 8 weeks. Additional littermates (n = 6) were sacrificed at 3 days of age to provide a developmental reference point. Brains were fixed by perfusion and stained by the Golgi-Cox method. The primary somatosensory, auditory and visual cortices were sectioned at 170 microns, and layer IV stellate neurons (n = 492) were digitized and 3-dimensionally reconstructed. Measurements of dendritic length, membrane surface area, total number of segments, number of 1st- through 7th-order dendrites, spine density, soma area, and soma form factor were taken. In auditory cortex neurons, outdoor pigs compared to indoor pigs had (a) significantly more primary dendrites, (b) significantly greater spine density, and (c) trends of increases both in number of 2nd- and 3rd-order dendrites and in total dendritic length. In visual cortex neurons, indoor pigs had significantly more 7th-order dendrites, whereas in all three cortical areas, the indoor animals had more 5th-order dendrites. Multiple morphological differences occurred in stellate cell populations between the three sensory areas of the Week 8 pigs. Also, within different cortical areas, dendritic morphology changed substantially from 3 days to 8 weeks of age. Further investigations are needed to determine which environmental factors are critical in producing the observed changes in brain morphology and whether other brain effects may be produced by varying developmental environments.

The effects of restraint using self-locking stanchions on dairy cows in relation to behavior, feed intake, physiological parameters, health, and milk yield

Holstein cows (n = 64) ranging from peak to end lactation were restrained in self-locking stanchions (i.e., head locks) for approximately 4 h/d for four periods in a modified switchback design. Milk yield, milk fat percentage, somatic cell count, and dry matter intake and dry matter intake were unaffected by restraint. Milk protein percentage was significantly lower for cows that were restrained. Plasma cortisol concentrations and the ratio of neutrophils to mononuclear cells were not significantly different between restrained and unrestrained (control) cows. No difference in the incidence of mastitis or other health concerns was noted. Behaviorally, cows that were locked in the stanchions spent significantly more time lying after release from restraint. For cows that were locked up, eating frequency over 24 h was significantly reduced, but dry matter intake was not affected. Total rumination frequency over 24 h was not significantly different for cows that were restraubed; however, cows that were restrained ruminated less during the day following release. Grooming was considered to be a behavioral need and was significantly increased during all times when cows were not locked up. Grooming was also one of the first behaviors performed following release. Acts of aggression were elevated during all periods following restraint, but oral behaviors, such as tongue playing and chewing on objects, drinking behavior, and resting postures were not affected. The use of self-locking stanchions did not appear to affect substantially the overall well-being of the cow.

Immunological and hematological characterizations of the wasting pig syndrome

After weaning, pigs may develop a wasting syndrome characterized by slow growth, decreased disease resistance, and increased mortality. This study was conducted to determine whether differences in immune indices exist between wasting and normal pigs of a common age. Treatments were normal controls (N), wasting pigs (WP), and WP treated with the neuroleptic drug amperozide (WPA). Blood samples were taken on the day of treatment (d 0) and 7 and 21 d after treatment. Cortisol concentrations and hematological values were measured, and functional immune assays were conducted on all samples. Body weight was lower (P < .05) for wasting pigs at the start of the study. Wasting pigs and WPA also had fewer (P < .05) white blood cells, lymphocytes, and monocytes than normal pigs. The neutrophil:lymphocyte ratio, an index of stress, was greater for WP and WPA (.79, .92, and .59 +/- .07 for WP, WPA, and N, respectively; P = .008). Functional in vitro immune assays did not differ between groups. Differences in numbers of lymphocytes and monocytes in wasting pigs may result from chronic stress and contribute to the decreased disease resistance and increased mortality seen in these pigs.

Sources of maternal odors and the development of odor preferences in baby pigs

Seven experiments utilizing 77 litters of piglets were conducted to determine the relative preferences or aversion of piglets for maternal olfactory cues. A Y-maze was used to test piglet preferences for two substances at any one time. A preference index was calculated from Y-maze data to identify whether piglets expressed a preference or aversion to the two substances tested in each session. The first two experiments examined piglet preferences for maternal fecal odors, colostrum, milk, urine and skin washings at 12 h and 7 d of age. Piglets preferred the odor of nipple washings and sow feces at 12 h of age. Piglets preferred sow fecal odors at 7 d of age in one study. The third study showed that piglets could discriminate between their mother's fecal odor and fecal odors from other sows. The fourth study examined piglet preferences for maternal fecal odors at birth, 12 h and 1, 3 and 7 d of age. At all ages tested except birth, piglets preferred sow fecal odors over water. The final three studies showed that piglets did not prefer to be near novel odors (orange and banana odors), nor did they prefer to be near the putative rat maternal pheromone, deoxycholic acid. In conclusion, piglets learn their mother's odor within the first 12 h of life. Piglets are most attracted to the odors associated with maternal feces and skin secretions. Piglet odor discriminatory ability is specific for maternal odors (not just odorous substances) and very acute (they can discriminate between mother and non-mother odors). When modifying piglet behavior to improve survival, the piglet's well-developed olfactory ability should be considered.

Sensory systems and nipple attachment behavior in neonatal pigs

The influence of piglet sensory systems and the role of odors from the sow's ventrum on piglet nipple attachment were investigated. In Experiment 1, four sows had their ventrum washed with organic solvents and four were unwashed control sows. Piglets were given one of four treatments shortly after birth: nares that were mechanically blocked (B), a lidocaine flush of the olfactory system (LFO), a saline flush of the olfactory system (SFO) or nontreated controls (C). Time to attach to a nipple, up to a maximum of 600 sec, was recorded. On unwashed sows, nipple attachment was affected (p less than 0.01) by piglet treatment. Piglets have B or LFO treatments took longer to attach to a nipple than SFO or C piglets. Piglets of all treatments took longer to attach to washed sows than to unwashed controls. Seven unwashed sows and their litters were used in Experiment 2. Piglets were tested after birth with one of the following treatments: an olfactory system flushed with lidocaine, lidocaine on nose (LN), lidocaine applied to the tongue (LT) or nontreated controls. All lidocaine-treated piglets took more time to attach than C piglets. Nipple attachment latencies were intermediate for LN or LT piglets. In Experiment 3, three unwashed sows and their litters were used. Treatments were: lidocaine applied to both the nose and the tongue (LNT), an olfactory system flushed with lidocaine or nontreated controls. LFO piglets had an increased latency to attachment compared to controls while LNT piglets were intermediate in latency to attach. Piglet olfaction, gustation and tactile sensory modalities as well as odors on the sow's ventrum influenced nipple attachment.(ABSTRACT TRUNCATED AT 250 WORDS)