Productive performance and reproductive characteristics of Morada Nova male lambs fed with high-energy diet.

Morada Nova breed sheep are without wool, tropicalized, small-sized animals, known for their high-quality meat and skin. Their body development naturally depends on the genetic potential and adequate nutritional support, which suggests that the offer of high-energy density diets positively influences their productive indicators. Thus, the present study investigated the effect of a high-energy diet for the Morada Nova lambs on body development and testicular function, considering their histomorphometric characteristics and seminal quality. Forty-two males (19.2 weeks, 20.7 ± 3.5 kg) were equally divided into two groups and fed with 2.05 Mcal (G7, n = 21) or 2.37 Mcal (G24, n = 21) of metabolizable energy/day, equivalent to 7% and 24% above the minimum for growing lambs. The animals were confined for 23 weeks (W0 to W23). Weight and body score differed significantly from the W1 (P < 0.05). From the W5, thoracic perimeter, body length, wither height, and rump attributes were higher in G24 (P < 0.05). The scrotal circumference and testicular volume were higher in G24 from the W3 (P < 0.05). Although testosterone levels were not affected (P = 0.05), the highest energy intake increased the diameter of the seminiferous tubules and the development of the epididymal epithelium (P < 0.05). This positively influenced the seminal quality and reduced the minor defects (21.87% vs. 17.13%) and the total spermatic defects (26.34% vs. 21.78%, P < 0.05). Thus, it is possible to employ higher levels of dietary energy for Morada Nova young males to express higher productive efficiency and earlier reproductive attributes of interest.

Determination of toxic metals in leather by wavelength dispersive X-ray fluorescence (WDXRF) and inductively coupled plasma optical emission spectrometry (ICP OES) with emphasis on chromium.

The tanning industry is one of the largest environmental polluters due to high generation waste in all production processes, but the tanning is particularly worrisome due to the use of significant amounts of chromium. Cr is an element potentially toxic to both health and the environment, depending on the concentration and the oxidation state. Cr(VI) can come in contact with human skin when using leather goods, which can cause allergies and dermatitis, besides being carcinogenic. Considering that approximately 90% of the world production of leather is performed with Cr salts, the determination of this element in leather is necessary to avoid exposure to the risks that the element can provide. The main goal of this study was the development of an alternative analytical method for the determination of Cr in leathers (ovine and bovine leather tanned with Cr and vegetable tannin) using wavelength dispersive X-ray fluorescence (WDXRF) for direct solid analysis. Besides performing analysis of the chemical composition and determination of Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Ni, Pb, Sb, Sr, Ti, and Zn in leather by inductively coupled plasma optical emission spectrometry (ICP OES). Principal component analysis (PCA) was also used in the evaluation of the WDXRF and ICP OES data sets. WDXRF calibration models for Cr presented satisfactory figures of merit and the analysis of the leathers revealed an alarming concentration of total Cr in the samples reaching 21,353 mg kg-1.

Thermoregulation of male sheep of indigenous or exotic breeds in a tropical environment.

Climate change has intensified the frequency of heat waves in the world, thereby exposing farm animals to stressful conditions. For better productive performance it is important to identify the most resilient genotypes. Thus, our objective was to evaluate the thermoregulatory responses of rams of tropical indigenous (Morada Nova and Santa Inês) and exotic breeds (Dorper and Texel), by monitoring the environmental and physiological indicators related to heat tolerance. The experiment was carried out in a tropical climate region (Cwa), in Brazil, for twelve months, which comprised spring, summer, autumn and winter. Thirty-three rams were divided into groups: Morada Nova (MN; n=8, red-coat), Santa Inês (SI; n=9, black-coat), Dorper (DO; n=8, white-coat) and Texel (TX; n=8, white-coat). The microclimatic variables were monitored, and the THI and BGHI comfort indices were calculated. Coat thickness and body surface temperatures were measured monthly, and serum triiodothyronine-T3 measurements and complete blood tests were performed. The physiological variables were evaluated every fifteen days and skin micro-biopsies were performed in the summer and winter for histological evaluation. During the warmer seasons, the THI and BGHI reached values that indicated thermal discomfort. TX showed higher coat thickness throughout the year, increased physiological variables related to thermolysis, and reduced T3 (P < 0.05). The internal temperature was permanently lower in the MN, SI and DO (P < 0.05). The body surface temperatures were affected by the coat characteristics and wool length. Hematological parameters varied in the seasons with the highest thermal conditions (P < 0.05). The MN showed larger sweat glands, while the area occupied by the sweat glands was higher in the SI. The DO showed higher hair density in the summer and winter (P < 0.05). The results indicated that the MN, SI and DO breeds overcome the thermal challenge more easily throughout the seasons due to specific adaptive morphological and physiological characteristics.

High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds.

This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1-animals maintained in the shade (11 to 12 h); period 2-animals exposed to sunlight (12 to 13 h); and period 3-animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased (P < 0.05), which matches a thermal discomfort situation. In period 3, the variables returned to baseline values and some values were lower than those in period 1. Semen quality and testicular parenchyma integrity suffered no negative effects with the thermal challenge. IRT ocular and IRT testicular were positively correlated (P < 0.05). It is concluded that MN and SIN rams had efficient thermolytic mechanisms that favor preserving gonadal functionality. The animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.

Avaliação histológica de peles de caprinos em idades diferenciadas / Histological evaluation of goat's hair at different ages

Objetivando-se analisar a pele de caprinos, identificando as diferenças estruturais histológicas, utilizou-se 16 animais machos mestiços da raça Alpina, com 4 animais em cada abate a partir dos 180 dias com intervalos entre cada abate de 45 dias. Após o sacrifício foram retiradas amostras de pele das regiões dorsal, paleta, ventre, anca e lateral. Estas amostras foram fixadas em Bouin e processadas histologicamente segundo rotina de inclusão em parafina. Os cortes de 5 mm foram analisados e fotomicrografados. A pele dos caprinos, com 180 dias de vida, mostrou-se com maior espessura da camada termostática da derme, consequentemente com grande densidade de folículos e glândulas. Com o aumento da idade os feixes de fibras do colágeno se desenvolveram aumentando a espessura da camada reticular.