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The present study aimed to evaluate the effects of rearing system and level of dietary protein supplementation on growth performance, metabolic profile, plasma leptin, and carcass composition of young Podolian bulls. At the beginning of the finishing period (about 14 mo of age), animals were divided into 3 groups according to rearing system and dietary protein level: indoor receiving a diet with 15% CP of DM (IND); and outdoor, at pasture, receiving a supplementation with 12% CP of DM (OUT12) or with 15% CP of DM (OUT15). Plasma leptin concentration increased (P < 0.05) with age, whereas it was unaffected by rearing system and protein level. Positive correlations between plasma leptin concentration, ADG (r = 0.861, P < 0.001), and blood glucose concentration (r = 0.977, P < 0.001) were observed, whereas NEFA and triglycerides were not correlated with leptin concentration. At the end of the finishing period (about 20 mo of age), young bulls in the OUT12 group showed greater (P < 0.05) cholesterol concentrations in blood than the OUT15 group, whereas the OUT15 group showed greater urea concentrations compared with IND (P < 0.01) and OUT12 groups (P < 0.001). Average daily gains, feed conversion ratio, and final BW were similar between groups. Intramuscular lipid content of LM, semitendinosus, and semimembranosus muscles was correlated with plasma leptin before slaughtering (r = 0.77, P < 0.01; r = 0.67, P < 0.01, r = 0.79, respectively). Correlations between plasma leptin and intramuscular fat were found starting from 18 mo of age for LM (r = 0.44; P < 0.05) and from 19 mo for semimembranosus (r = 0.56; P < 0.05) and semitendinosus (r = 0.58; P < 0.05). Mean value of intramuscular fat and intramuscular fat of LM was greater in OUT15 than OUT12 (P < 0.05). No differences were found between 12 and 15% CP supplementations for growth and carcass data. Therefore, we conclude that the extensive rearing system supplemented with 12% CP may be adequate to sustain good growth performance and carcass quality from the Podolian breed. These data also provide confirmation that leptin, in cattle, is directly related to nutritional status and may represent a suitable predictor for body fat starting from 1 mo before slaughtering. Key words: carcass composition, leptin, metabolic profile, Podolian cattle, protein level, rearing system

The aim of the present study was to estimate the genetic variability of the Gentile di Puglia sheep breed by using microsatellite markers, to provide information useful for conservation. The DNA of 82 animals, belonging to 6 different farms, was analyzed at 19 microsatellite loci. The number of alleles, allele frequencies, deviations from Hardy-Weinberg proportions, linkage disequilibrium among loci, genetic similarity, genetic distances, and molecular coancestry-based parameters were calculated. Seventeen out of 19 microsatellites showed heterozygote deficiency in the whole population, although only 4 (OarAE129, ILSTS28, ILSTS5, MAF33) showed significant deviations from Hardy-Weinberg proportions (P < 0.01). The genetic similarity (an index of allele sharing among individuals) within the whole population was low (0.318), and the average number of alleles per locus was quite high (9.68). The results obtained highlighted a population presenting both a deficiency of heterozygotes and great genetic variability. These results suggest that stratification of the breed in subpopulations, probably derived from different farm management in each herd, led to a population characterized by great genetic diversity among different herds and by great similarity within each herd. Moreover, in the past, Gentile di Puglia sheep have undergone a strong numeric decline, involving genetic drift effects and considerable consanguinity within the breed. Key words: genetic variability, Gentile di Puglia sheep breed, microsatellite marker

A 6-wk trial was performed with thirty-six lactating Comisana ewes during the summer of 2001. The animals were divided into three groups of 12, which were designated low (LVR), moderate (MVR), and programmed (PROGR) ventilation regimens. In LVR and MVR rooms, fans provided 10 ventilation cycles of 12.5 and 25 min/h, respectively, whereas in the PROGR room, the fan was programmed to operate at 30[degrees]C air temperature and 70% relative humidity. Mean ventilation rates were 33, 66, and 173 [m.sup.3]/h per ewe in LVR, MVR, and PROGR rooms. Air concentrations of microorganisms and dust and of gaseous pollutants were measured twice weekly. Respiration rate and rectal temperature were monitored throughout the trial at 1430. Behavioral traits of ewes were recorded once per week from 0930 to 1230. Cell-mediated immune response to phytohemagglutinin at d 3, 20, and 40 and humoral response to chicken egg albumin at d 11, 21, 30, and 40 were determined. At d 37, ewes were injected with 2 IU porcine ACTH/kg body [weight.sup.0.75] and subjected to blood sampling for evaluation of cortisol concentrations immediately before and 1, 2, and 4 h after ACTH injection. Milk yield was recorded daily. Individual milk samples were analyzed weekly for composition and renneting parameters and fortnightly for bacteriological characteristics. Averages of temperature-humidity index values were 78.9, 76.8, and 74.5 in LVR, MVR, and PROGR rooms, respectively. The LVR and MVR treatments resulted in higher N[H.sub.3] and C[O.sub.2] air concentrations than PROGR treatment (P < 0.05). The LVR and MVR ewes had higher rectal temperatures than PROGR ewes (P = 0.001). LVR animals also exhibited higher idling compared to PROGR (P < 0.01) and lower feeding times than MVR (P < 0.05) and PROGR animals (P < 0.01). Ewes under the LVR treatment displayed significant lower averages of antibody titers and higher plasma cortisol levels than PROGR (P < 0.01) and MVR ewes (P < 0.05) 60 min after ACTH injection. The LVR treatment resulted in lower yields of milk (P < 0.01) and reduced feed efficiency (P < 0.01) than PROGR treatment. Results suggest that a fan-ventilated system, providing ventilation cycles during the warmest hours of the day and the night at a mean ventilation rate of 66 [m.sup.3]/ewe per hour, may sustain the performance and welfare in lactating ewes raised in warm climates during summer. A ventilation regimen, programmed to operate over upper critical air temperature and relative humidity, may be economically unattractive under these conditions. Key Words: Hydrocortisone, Immune Response, Milk Yield, Sheep, Ventilation

The experiment involved 40 mid-lactating Comisana ewes. The animals were housed in straw-bedded pens and assigned to a control group (n = 10) and two test groups of 15 subjects each. Control ewes were never moved from their pen and peers throughout the experiment period, whereas test animals were subjected to either regrouping (RG) or regrouping and relocation (RGRL) three times at weekly intervals (d 7, 14, and 21 of the trial). Three behavioral recordings were conducted after each social and pen exchange over a 6-h period (1000 to 1600). Animals from groups RG and RGRL were bled immediately before each regrouping and relocation and 15 and 60 min afterward. The phytohemagglutinin skin test was performed at d 9, 16, and 23. Milk yield was recorded when the ewes were mixed and moved, and before and after each mixing and moving procedure. Individual milk samples were analyzed for composition, renneting parameters, and bacteriological characteristics; samples with more than [10.sup.6] somatic cells/mL were cultured for mastitis-related pathogens. Control ewes spent more time lying than groups RG (P [is less than] 0.001) and RGRL (P [is less than] 0.01) and less time in ambulatory activities than RGRL sheep (P [is less than] 0.05). Moved and remaining ewes showed a higher number of aggressive interactions than control subjects (P [is less than] 0.001 and P [is less than] 0.01, respectively). Control sheep showed the highest cell-mediated immune response compared with both moved and mixed ewes (P [is less than] 0.001 and P [is less than] 0.01, respectively). The RGRL ewes gave lower yields of milk than did the control ewes on the days after the first (P [is less than] 0.05) and the second (P [is less than] 0.01) change of pen and peers. The RGRL ewes also had a lower fat content (P [is less than] 0.05) than control ewes in the milk yielded on the day of the first regrouping and relocation and a lower milk protein content (P [is less than] 0.05) on the following day. The RG treatment resulted in the ewes yielding milk with a lower fat content (P [is less than] 0.01) on the day of each mixing procedure as compared with controls and in a decreased milk protein content on the days after the first (P [is less than] 0.05) and the second regrouping (P [is less than] 0.01). One case of subclinical mastitis was recorded in both the RG and RGRL groups, whereas no cases were detected in control group. These findings suggest that regrouping and relocation may cause increased aggression, altered immune responses, and short-term effects on the production performance of lactating ewes. These practices should be performed by attempting to minimize their impact on animal welfare. Key Words: Group Behavior, Immunity, Milk Yield, Sheep