Plasma cortisol and ACTH concentrations in the warmblood horse in response to a standardized treadmill exercise test as physiological markers for evaluation of training status.

Reliable physiological markers for performance evaluation in sport horses are missing. To determine the diagnostic value of plasma ACTH and cortisol measurements in the warmblood horse, 10 initially 3-yr-old geldings of the Hannovarian breed were either exposed to a training schedule or served as controls. During experimental Phase 1, horses were group-housed, and half of the horses were trained for 20 wk on a high-speed treadmill. During Phase 2, groups were switched and one group was trained for 10 wk as during Phase 1, whereas the control group was confined to boxes. During Phase 3 horses were initially schooled for riding. Thereafter, all horses were regularly schooled for dressage and jumping, and half of the horses received an additional endurance training for 24 wk. During all phases horses were exposed at regular intervals to various standardized treadmill exercise tests. During and after the tests frequent blood samples were taken from an indwelling jugular catheter for determination of ACTH and cortisol. Treadmill exercise increased both hormones. Maximum ACTH concentrations were recorded at the end of exercise, and maximum cortisol levels were recorded 20 to 30 min later. Except for one test there were no differences in ACTH levels between trained horses and controls. There was no significant effect of training on the cortisol response (net increase) to treadmill exercise in any of the tests during Phase 1. During Phase 2 higher cortisol responses were recorded in controls than in trained horses (P < .05) after 10 wk of training (controls confined to boxes). During Phase 3 plasma cortisol responses were also higher in controls than in trained horses (P < .05 after 6, 18, and 24, P < or = .07 after 12 wk of training) when the inclination of the treadmill was 5%, but not at 3%. There was no overlap in net cortisol responses at 30 min between trained and untrained horses. An ACTH application after 24 wk of training resulted in higher cortisol responses in controls than in trained horses (P < or = .05), without any overlap between the groups at 30 min after ACTH. Plasma cortisol responses to either treadmill exercise or ACTH injection may be a reliable physiological marker for performance evaluation. Prerequisites are sufficient differences in training status and sufficient intensity of exercise test conditions.

Studies on a local effect of boar seminal plasma on ovulation time in gilts.

Previous studies showed that intrauterine infusion of seminal plasma at the onset of oestrus could advance ovulation in pigs, possibly to enhance the chances of fertilization by optimizing the chronological events of fertilization. This effect has been attributed to a local unilateral mechanism whereby infusion into a single uterine horn advances ovulation in the adjacent ovary. The present study was designed to elucidate possible mechanisms of local signal transduction. In a series of five experiments using 43 gilts, the ovarian response was investigated after infusion of seminal plasma at different sites of the female reproductive tract. The time of ovulation was detected sonographically at 4- or 2-h intervals. Single uterine horn infusion of 100 ml seminal plasma advanced ovulation on the ipsilateral ovary by 9.3 h (mean) compared with the contralateral ovary. Dissection of the ipsilateral isthmus abolished the unilateral seminal plasma effect. Unilateral infusion of 50 microliters or 1 ml seminal plasma or 50 microliters of the concentrated 1-10 kDa fraction in the lower isthmus was ineffective. Application of 5 ml seminal plasma into the tip of a ligated uterine horn lead to 3.6 h (mean) earlier ovulation on the adjacent ovary. In contrast, the infusion of 5 ml NaCl showed no effect. Application of 5 ml seminal plasma in the middle of the uterine horn between two ligatures was ineffective. It is concluded that, for the transduction of the local signal involved in the advancement of ovulation, contact of seminal plasma with the epithelium of the utero-tubal junction is essential.

[In vivo investigations of stress susceptibility in pigs by means of magnetic resonance spectroscopy]. / In-vivo-Untersuchungen zur Stressanfälligkeit beim Schwein mit Hilfe der Magnet-Resonanz-Spektroskopie.

31P nuclear magnetic resonance spectroscopy was performed on 19 to 55 kg weighing pigs of different MHS genotypes to study the changes of phosphorus components (inorganic phosphate --Pi, phosphocreatine--PCr and adenosine triphosphate--ATP) of muscle metabolism as well as intramuscular pH under application of halothane. Aim of the present study was to observe the changes in energy metabolism and to perform a comparison with also measured blood parameters. Both, NN and Nn pigs did not show any changes during halothane exposure in phosphorus spectra, but in all animals a partially metabolically compensated respiratoric acidosis was found. In all MHS positive pigs a rapid fall of PCr and a corresponding raise of Pi levels in muscle was observed.

LH profile and advancement of ovulation after transcervical infusion of seminal plasma at different stages of oestrus in gilts.

The influence of a transcervical infusion of seminal plasma on preovulatory LH profiles and the advancement of ovulation after seminal plasma infusion for different times during oestrus were investigated using the single uterine horn infusion technique (Mariensee model), in combination with transcutaneous sonographic monitoring of the ovaries. Preparative surgery in 23 German Landrace gilts comprised the detachment of the left uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. In six gilts fitted with a permanent jugular vein catheter the patent horns were administered a transcervical infusion of seminal plasma (n = 5 cycles) or PBS (n = 4 cycles) immediately after the detection of oestrus by a teaser boar. In addition, 17 non-catheterized gilts received infusions of seminal plasma either 0 h (n = 3 gilts), 16 h (n = 7 gilts) or 24 h (n = 7 gilts) after the detection of oestrus. Seminal plasma infusion at the onset of oestrus provoked ovulation in the ipsilateral ovary of the treated horn 8.5 +/- 0.9 h earlier than in the contralateral (control) ovary. Seminal plasma did not influence the LH profile compared with PBS (P > 0.05), but shortened the interval between the LH peak and ipsilateral ovulation to 23.4 +/- 4.0 h compared with 31.8 +/- 3.4 h in the contralateral ovulation (P < or = 0.01). Infusion 16 h after the onset of oestrus reduced the effect to 4.6 +/- 3.8 h with a wide range of 0-8 h (P < 0.01). The effect was more pronounced in gilts with long intervals between the onset of oestrus and contralateral ovulation compared with earlier ovulation on the control ovary. Seminal plasma infusion less than 16 h before contralateral ovulation and 24 h after the detection of oestrus had no effect. It is concluded that transcervical infusion of seminal plasma early in oestrus synchronizes the variable intervals between the onset of oestrus and ovulation in sows by a locally active mechanism.

Effect of ovariectomy on bone histology and plasma parameters of bone metabolism in nulliparous and multiparous sows.

To investigate the suitability of the pig as animal model for postmenopausal osteoporosis, effects of ovariectomy (OVX) on bone metabolism and histology were studied in two groups of sows (9 months, nulliparous or 35 months, multiparous). A standard diet of about 1.5% calcium (Ca) was fed till sacrifice at either 12 or 20 months post OVX when mineral content and histology were studied in representative bone specimens of proximal tibia, iliac crest and lumbar vertebrae. At 4, 8, 12, and 18 months post OVX, total and bone-specific alkaline phosphatase (APt, APb) calcidiol, calcitriol and parathyroid hormone (PTH) were measured in plasma. In young sows OVX did not significantly affect plasma variables except for calcitriol, which was higher at 4 months post OVX. No significant differences between OVX or control animals were observed in the variables of bone chemical and histological analyses, neither 12 nor 20 months post OVX. In multiparous sows OVX significantly increased PTH plasma concentrations at 8 months post OVX and plasma calcitriol, APt and APb at 12 months post OVX. All effects were moderate and transient. OVX did not significantly affect the variables of bone chemical and histological analyses neither 12 nor 20 months post OVX. Although undoubtedly the clinical-chemical changes observed were not accompanied by any histomorphometric signs of osteopenia/osteoporosis, it must be left to future experiments as to whether this resulted from the ample calcium supply provided. This possibility is supported by recent observations showing that porcine osteopenia could be induced by OVX in animals maintained on only 0.75% dietary calcium but not on higher (0.9%) Ca regimens.

Advanced ovulation in gilts by the intrauterine application of a low molecular mass pronase-sensitive fraction of boar seminal plasma.

The shortening of the time interval between the onset of oestrus and ovulation in sows by the transcervical administration of seminal plasma was investigated in 23 German Landrace gilts, using the technique of single horn infusions (Mariensee model) in combination with the transcutaneous sonographic monitoring of ovaries. Preparative surgery comprised the detachment of the left uterine horn from the corpus, leaving the caudal end open to the peritoneal cavity but sealing the corpus wound. The left ovary was loosely tied to the ventral abdominal wall for better sonographic distinction. The animals were used in two to four consecutive cycles. After detection of oestrus by the teaser boar, the patent (right) horns were filled by transcervical infusion of 100 ml of a variety of test solutions. Ovulation was probed by transcutaneous sonography at intervals of 4 h thereafter. Native seminal plasma provoked ovulation in the ipsilateral ovary of the treated horn 10.7 h earlier than in the contralateral ovary. This effect was reduced to 7.3 h after charcoal treatment of seminal plasma; addition of 10 micrograms oestradiol restored the effect in full, while 10 micrograms of oestradiol in PBS shortened the time interval to only 3.3 h versus the control ovary. Little effect was seen with oestrone sulfate, none with prostaglandins in PBS or with PBS alone. The preliminary characterization of the nonsteroidal component of seminal plasma advancing ipsilateral ovulation after transcervical infusion suggests a proteinaceous nature. The activity resides in the 1-10 kDa fraction separated by ultrafiltration and is lost after treatment with pronase.

[The quantitative passage of immunoglobulins from the intestine into the blood vessels in newborn lambs]. / Untersuchungen zum quantitativen Ubergang von Immunoglobulinen aus dem Darm in die Blutbahn neugeborener Lämmer.

A trial with 69 lambs examined the effect of the feeding regime on the transfer of colostral immunoglobulins from the intestinal lumen to the circulating blood. The lambs received 125 ml of bovine colostral milk per kg birth weight at each feeding in the first 24 hours after birth. There were four experimental groups. Feeding intervals were either 2 or 6 hours and the milk was administered with or without doubling the fluid volume by addition of tap water. Serum concentrations of IgG1, IgG2, IgM and IgA were measured during the experimental period and the transport efficiency index for each isotype was calculated. The transport efficiency index represents the relationship between the amount of immunoglobulin administered in colostral milk and the concentration measured in the blood. Feeding in 2 hour intervals produced maximum immunoglobulin concentrations at 30 hours, while 6 hour feeding intervals achieved the same maximal levels at 24 hours. The relative proportions of the four immunoglobulin isotypes measured in the blood were unaffected by the feeding interval. Doubling the fluid volume administered while holding the absolute amount of colostral milk constant, resulted in a disproportionate increase in blood IgG1 concentration as compared to the other isotypes. Concentrations for IgG2, IgM and IgA remained essentially the same as those achieved with undiluted colostral milk. The feeding regimes tested did not affect endogenous immunoglobulin synthesis, growth rate or the health of the lambs.

[The "waiting period" for follow-up administration of bovine colostrum to newborn lambs]. / Untersuchungen über "Wartezeiten" mit anschliessender Verabreichung von Rinderkolostralmilch bei neugeborenen Lämmern.

Extent and duration of the permeability of the small intestine of newborn lambs for intact proteins from cow's colostrum was analyzed in five groups of animals. Cow's colostrum in quantities of 200 ml/kg birth weight, was offered in 3-hr intervals for 24 hrs, beginning either immediately after birth or after fasting, for 12 and 24 hrs respectively. In two groups each either 5% glucose solution or saline was offered to the fasting animals. The following results were obtained: 1. All lambs fed immediately after birth drank eagerly. The intake in all fasting groups dropped between 12 and 24 hrs of the feeding period. 2. While the duration of the permeation of the small intestine for intact proteins remained unaffected by the various regimens, fasting with or without supplementation decreased the maxima. 3. The decrease in protein permeation was class-depending as demonstrated by the lower levels of bovine IgM in the sera of fasting lambs. 4. The permeability of the small intestine for proteins was substantially reduced by 5% glucose. The difference between fasting lambs or lambs with saline substitution was minimal. 5. All lambs fed immediately after birth survived. The losses in the other groups amounted to 29% after 12 hrs of starving, 33% after 24 hrs of starving, 30% after starving with glucose supplementation and 50% after saline solution. 6. The surviving animals showed no differences in weight gain.

[The significance of meat quality in marketing]. / Die Bedeutung der Fleischqualität bei der Vermarktung.

Food quality in general and meat quality in particular are not only evaluated by means of objective quality traits but the entire production process is gaining more attention by the modern consumer. Due to this development quality programs were developed to define the majority of the processes in all production and marketing steps which are again linked by contracts. Not all of these items are quality relevant, but are concessions to ethic principles (animal welfare etc.). This is demonstrated by the example of Scharrel-pork production. The price differentiation at the pork market is still influenced predominantly by quantitative carcass traits. On the European market quality programs still are of minor significance. Premiums which are paid for high quality standards are more or less compensated by higher production costs and lower lean meat percentages, which must be expected in stress susceptible strains. The high efforts to establish quality programs, however, help to improve the quality level in general, and secure the market shares for local producers.

[Necessary care of newborn lambs using ovine colostrum. 2. Duration of administration]. / Erforderliche Versorgung neugeborener Lämmer mit Schafskolostralmilch. 2. Mitteilung: Verabreichungsdauer.

Sheep colostrum, pooled from 0-12 h milkings, was fed to 38 newborn lambs for either 6, 12, 18 or 24 hrs after birth. The influence of the duration of feeding periods on the transintestinal passage of immunoglobulins, the growth performance, the loss rate and the onset of immunoglobulin synthesis were investigated by monitoring the serum concentrations of IgG1, IgG2, IgM and IgA during months 1 through 9 of life. Feeding of 3 portions of 100 ml at 2 h intervals resulted in lower serum levels of Ig's than the extension of the feeding to 12 x 100 ml every second hour. There was, however, no difference in the onset of endogenous Ig production between both groups. Growth performance and the loss rate were also identical.

[Necessary provision of newborn lambs with sheep colostrum]. / Erforderliche Versorgung neugeborener Lämmer mit Schafskolostralmilch. 1. Mitteilung: Verabreichungsintervall.

Twenty new-born lambs of each of the breeds Schwarzkopf, Texel and Finnish were fed with 600 ml of pooled colostrum (0-12 h) on the first day of life. The total allocation was fed in portions ranging from 25 to 150 ml at intervals of 1, 2, 3, or 6 hours. The effect of the different intervals and portion volumes on the transintestinal passage of immunoglobulins, the onset of endogenous synthesis, the growth performance of the lambs and the mortality rate was investigated. The concentrations of IgG1, IgG2, IgM and IgA in the sera were analyzed over the course of a nine-week period. 1. The extent of passive immunization by transintestinal passage remained essentially unaffected by different feeding schedules. 2. There was also no effect on the onset of endogenous Ig synthesis. 3. Growth performance and mortality rate likewise showed no discernible differences.

[Transcervical injection into the uterine lumen of castrated swine as a cell and organ biological research design. The Mariensee model]. / Die transcervicale Injektion in das Uteruslumen von kastrierten Schweinen als zell- und organbiologische Versuchsanordnung. Das Mariensee Modell.

The technique and the equipment necessary for the transcervical intrauterine injection in trained, ovariectomized pigs is detailed. Experimental groups of 14-16 week-old animals are recruited from German landrace litters with large numbers (4-9) of females. A silastic tubing containing a crystalline suspension of estradiol in propylene glycol is subcutaneously implanted behind the right ear. Ovariectomy and the detachment of the left uterine horn from the cervix are performed 7-10 days later. The animals are then kept for 6-7 weeks in ventilated stables, heated to 20 degrees C in wintertime, with 12 hr light dark cycle, free access to water and semi-ad libitum supplies of pelleted standard feed. The silastic implant gives rise to plasma levels of 8-12 pg estradiol/ml and still contains crystalline sediments when removed before the experiment. The manipulations for the transcervical, intrauterine instillation of solutions, imitating the reproductive action of the boar, are practiced daily for at least one week. The animals learn quickly to enter a restraining box, which is facilitated by the simultaneous offering of pellets drenched with root beer. The intrauterine injections proceed thereafter without any signs of stress from the animals. Stress is also avoided during slaughter by unexpected electric stunning on leaving the box, followed by exsanguination. Uteri are quickly excised and chilled in crushed ice until processed. One to two grams of endometrium cells can be harvested by curettage from each, treated and untreated (detached) horn. The Mariensee model allows for defined kinetic analyses of treated cells and provides nontreated controls from the same animal. It combines the advantages of in-vivo and in-vitro experiments.

[Physiologic reactions during the slaughter of cattle and sheep with and without stunning]. / Physiologische Reaktionen bei der Schlachtung von Rindern und Schafen mit und ohne Betäubung.

In a first trial the cortical activity of cattle and sheep was tested using only an electrocorticogram (ECoG). The results showed a shorter phase after sticking or the ritual slaughter cut respectively, until the ECoG disappears in stunned animals. However, considering the time between stunning and the cervical state, the interval until disappearance of the ECoG was prolonged in the stunned animals. The observed time differences, however, are only a tendency and not statistically confirmed. Insofar, concerning animal protection, the different slaughter methods could be regarded equivalent. A second trial was designed in a manner to allow a more exact interpretation of the ECoGs and was completed by measuring visually and somatosensorically evoked potentials. Additionally, in contrast to the first trial, only adult cattle were used here. The results revealed shorter intervals until disappearance of cortical activities when using captive-bolt stunning. Also the variance was much lower in this trial than after ritual slaughter. The mean of the time differences was relatively low (5.5 seconds). It was especially remarkable that after captivebolt stunning absolutely no evoked potentials could be registrated, whereas these potentials lasted for 77 seconds (somatosensorically evoked potentials) and 55 seconds respectively (visually evoked potentials) after the ritual slaughter cut. Thus, after ritual slaughter a nervous conduction was measured up to 126 seconds in the extreme cases. However, from the results obtained it can not be concluded whether or not pain sensitivity occurred in the animals.

Cortical function in cattle during slaughter: conventional captive bolt stunning followed by exsanguination compared with shechita slaughter.

Brain function was examined in adult cattle after conventional captive bolt stunning or shechita slaughter, using eight animals in each treatment. The times to loss of evoked responses (visual and somatosensory) and spontaneous activity in the electro-corticogram were used to determine the onset of brain failure. Captive bolt stunning followed by sticking one minute later resulted in immediate and irreversible loss of evoked responses after the stun. Spontaneous cortical activity was lost before sticking in three animals, and in an average of 10 seconds after sticking in the remaining five animals. The duration of brain function after shechita was very variable, and particularly contrasted with captive bolt stunning with respect to the effects on evoked responses. These were lost between 20 and 126 seconds (means of 77 seconds for somatosensory and 55 seconds for visual evoked responses) and spontaneous activity was lost between 19 and 113 seconds (mean 75 seconds) after slaughter.

Effects of Sarcocystis miescheriana infection on carcass quality and on the water-binding capacity of the meat of halothane-tested fattening pigs.

Ten halothane-positive pigs (stress sensitive, group A) and ten halothane-negative pigs (stress insensitive, Group C) with a mean body weight of 36 kg were each inoculated orally with 50,000 sporocysts of Sarcocystis miescheriana. Twelve halthane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks post infection (p.i.) the lean: fat ratios of the pigs of the infected groups A and C were lower (A, 1:0.41 +/- 0.09; C, 1:0.50 +/- 0.10) than those of the pigs of the non-infected groups B and D (B, 1:0.50 +/- 0.08; D, 1:0.55 +/- 0.08). The back-fat thickness, the fat thickness 'A' and the fat thickness 'B' were thinner in infected pigs than in non-infected pigs. The difference in Lendenstärkespeckquotient (Loin Fat Thickness Quotient) (LSQ) between infected and non-infected pigs was not statistically significant. The values of the water-holding capacity were lower in infected pigs than in non-infected pigs, the difference being statistically significant only in the halothane-negative groups (C, 0.45 +/- 0.02; D, 0.48 +/- 0.04). The water-absorbing capacity was significantly higher in the infected groups (A, 5.92 +/- 3.99%; B, 2.26 +/- 1.08%; C, 8.96 +/- 2.90%; D, 4.97 +/- 2.51%). In conclusion, it can be said that there was a slight tendency towards a better carcass quality and a better water-binding capacity in infected pigs, although this was combined with reduced growth rates.

[Stress, health and production in swine]. / Stress, Gesundheit und Leistung beim Schwein.

The "porcine stress syndrome" is a well established concept. Effects exerted on part of the meat type pig populations by their increased susceptibility to stress, resulting in meat quality defects, are meant by it. The problem of stress is rather a complex phenomenon. Stress is a part of daily life and can have negative as well as positive effects on performance and health, depending on its intensity and duration. These connections are discussed in the following paragraphs: 1. Definition of stress, and of stress-related reactions and possibilities of their assessment. 2. Stressors and their effects on the performance and health of pigs with regard to genetic dispositions. 3. Conclusions for the avoidance of stress effects in pig production.

Effects of Sarcocystis miescheriana infection on carcass weight and meat quality of halothane-tested fattening pigs.

Ten halothane-positive pigs (Group A) and ten halothane-negative pigs (Group C) were each infected per os by 50,000 sporocysts of Sarcocystis miescheriana when they had reached a mean body weight of 36 kg. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks p.i. (post infection), the pigs were slaughtered and the carcass weights and the number of cystozoites in several muscles were determined. In addition, 11 parameters of meat quality were measured in Musculus longissimus dorsi (M.l.d.) and Musculus semimembranosus (M.s.): pH and temperature 30 min and 24 h p.m. (post mortem), electrical conductance 45 min, 60 min and 24 h p.m., colour brightness (FOP) and rigor values 30 min and 24 h p.m. Additionally, the AMP, ADP, ATP and lactate contents were determined in samples from the M.l.d. The mean carcass weights of the infected pigs (A: 79.9 +/- 6.9 kg; C: 76.3 +/- 11.6 kg) were lower than those of the pigs of the non-infected groups (B: 85.7 +/- 8.0 kg; D: 87.5 +/- 7.0 kg). The pH values at 24 h p.m. were significantly higher in the M.l.d. of infected pigs than in M.l.d. of non-infected pigs. Electrical conductance in the M.s. at 45 min p.m. was significantly higher in the halothane-negative infected pigs, but at 24 h p.m., the mean values of electrical conductance in the M.s. of the pigs of both infected groups were significantly lower than in the control groups. FOP values at 30 min p.m. were raised in the M.l.d. of the halothane-negative infected pigs, but at 24 h p.m., differences between infected and non-infected pigs could no longer be found. Mean rigor values were higher in the pigs of the infected groups at 24 h p.m., but the difference from the non-infected groups was not statistically significant. AMP was reduced only in the meat of halothane-positive infected pigs, while lactate was reduced in both infected groups. Using conventional methods for the determination of meat quality, the hypothesis of impaired meat quality in Sarcocystis-infected pigs could not be confirmed. The meat quality parameters investigated were, in part, better in infected pigs than in non-infected controls.

Biosynthesis and posttranslational finishing of the estradiol receptor.

The time course of subcellular receptor distribution in porcine endometrial epithelium was studied after intrauterine administration of estradiol alone or in combination with puromycin. In untreated cells, the major proportion of receptor is associated with cytoplasmic membranes. The solubilization of receptor from isolated nuclei is independent of their estradiol content. Smooth cytoplasmic membranes are the site of origin of receptor which is swiftly translocated into the nucleus in a 1:1 ratio with the hormone after exposure of the cells to estradiol. Simultaneously administered puromycin delays receptor synthesis and reveals that the nuclear passage of receptor is terminated by receptor degradation. The synthesis of receptor proceeds in rough endoplasmic membranes. A subsequent finishing and deposition in smooth membranes depends on intact protein synthesis.

A case of "reversed cannibalism": the piglets damaging the sow.

Sows introduced to a new housing system containing farrowing pens with slatted floor showed increased occurrence of lesions of the vulvar region, caused by the piglets during the later stages of the lactation period. An investigation was undertaken in which the activity of the piglets, particularly rooting and investigatory behavior, was examined and compared to that of piglets kept on straw. Although the occurrence of vulvar lesions disappeared spontaneously before the conduction of the investigation, the results revealed that piglets on slatted floor spent significantly more time chewing on inappropriate objects such as other group members or the vulva of the sow, whereas the rooting and investigatory behavior of piglets raised on straw was almost exclusively directed towards the straw. The results confirm previous observations that piglets living in a relatively poor environment show a greater tendency to direct their activity towards inappropriate objects. If the housing system is otherwise healthy, the change in behavioral activity remains insignificant. If, however, other minor disturbances occur in the system, in the present case clinically insignificant lesions on the vulva of the sow caused by the new slatted floor, aggravation of the lesions can occur due to this change in piglet activity.