Reproductive traits in Ethiopian male goats

This thesis characterizes reproductive traits of Ethiopian male goats raised under extensive husbandry and subjected to differential nutritional management. A total of 177 extensively-managed indigenous bucks of 5 breeds (i.e., Arsi–Bale [AB], Central Highlands [CH], Afar, Boran and Woito-Guji [WG]) were selected following stratified random sampling.The bucks were compared according to three age classes (<14 mo [young], 14–19.5 mo [intermediate] and 19.6–24 mo [old]) to determine whether breed and age influenced body size, testicular traits and epididymal sperm morphology. Bucks of a single goat breed (Ogaden; n= 35), selected by simple random sampling, were used to determine responses to differential nutritional treatments. Dietary treatments consisted of native hay fed ad libitum (control, C), native hay supplemented with 1% of body weight (BW) of agro–industrial by-products (Treatment 1, T1), native hay supplemented with 1% of BW of khat (Catha edulis) leftovers (Treatment 2, T2) and khat leftovers fed ad libitum (Treatment 3, T3). Breed, age and their interaction affected (P<0.05 to P<0.001) BW, body condition score (BCS), scrotal circumference (SC) and testicular weight (TW). Comparing all age classes, Boran displayed the highest (P<0.05) BW, greatest SC and heaviest TW, while Afar displayed the lowest values for these characteristics. Expressed as percentage of BW, Afar bucks had the highest TW. Regarding epididymal sperm morphology, most acrosome defects were displayed by CH (P<0.05) while AB mainly showed loose sperm heads (P<0.05). Bucks from a lowland agroclimate (i.e., Afar, Boran and WG) displayed more total sperm-head abnormalities (P<0.05) than did bucks of highland breeds (i.e., AB and CH). Younger bucks showed more (P<0.05) loose sperm heads, while older bucks had more (P<0.05) acrosome defects. Bucks fed according to the T1–T3 treatments improved (P<0.05) their BW, BCS, testicular size and testicular weight compared to controls. Goats in treatment groups T1–T3 showed higher (P<0.05) sperm motility, sperm concentration per mL and total number of spermatozoa per ejaculate compared to controls. Of groups T1–T3, bucks in T3 had the highest BW and testicular size. Feeding goats according to the T1–T3 regimes improved (P<0.001) feed dry matter (DM) and nutrient intake, and the occurrence of morphologically normal spermatozoa, compared to controls. Of the T1–T3 treatments, feeding according to T3 and T2 resulted in higher (P<0.05) DM, organic matter and gross energy intakes, while T1 followed by T3 resulted in the highest (P<0.05) crude protein intake, and T3 the highest occurrence of morphologically normal spermatozoa. In conclusion, body size, testicular traits and sperm morphology of Ethiopian bucks raised under extensive management were influenced by breed and age. Nutritional supplementation with khat leftovers and an agro–industrial by-product mix improved feed intake, growth and semen characteristics; these feedstuffs could be considered alternative feed resources to enhance goat production under smallholder farming systems in Ethiopia

Features of reproduction and assisted reproduction in the white (Ceratotherium simum) and black (Diceros bicornis) rhinoceros

Despite the worldwide increase of rhinoceros calf numbers, the growth of the population of white and black rhinoceros is slowing down mainly due to anthropogenic causes, such as poaching and habitat loss. Assisted reproduction is one of the methods of preserving the valuable genomes of these animals from being lost, and assists in breeding them in captivity to maintain the specie(s) numbers and provide an option for possible reintroduction into the wild. Since wild rhinoceros are difficult to handle and examine clinically, most of the current information available on their reproductive characteristics has been gained from captive rhinoceros populations. Nevertheless, very little is known about rhinoceros reproduction. Since the rhinoceros belongs to the odd-toed ungulates (Perissodactyls) group, like the horse and the tapir, the horse has been proposed as a suitable model to study reproduction and artificial reproductive techniques in the rhinoceros. In this review, the current knowledge of the reproduction of the rhinoceros is summarized

Auditory communication in domestic dogs: vocal signalling in the extended social environment of a companion animal

Domestic dogs produce a range of vocalisations, including barks, growls, and whimpers, which are shared with other canid species. The source–filter model of vocal production can be used as a theoretical and applied framework to explain how and why the acoustic properties of some vocalisations are constrained by physical characteristics of the caller, whereas others are more dynamic, influenced by transient states such as arousal or motivation. This chapter thus reviews how and why particular call types are produced to transmit specific types of information, and how such information may be perceived by receivers. As domestication is thought to have caused a divergence in the vocal behaviour of dogs as compared to the ancestral wolf, evidence of both dog–human and human–dog communication is considered. Overall, it is clear that domestic dogs have the potential to acoustically broadcast a range of information, which is available to conspecific and human receivers. Moreover, dogs are highly attentive to human speech and are able to extract speaker identity, emotional state, and even some types of semantic information

Disrupting effect of androgens in postnatal female domestic cats

To test the hypothesis that in domestic cats, postnatal androgens induce sterility, the aims of this study were to describe the reproductive effects and the clinical safety of a postnatal administration of a long term release androgen in this species. Thirteen newborn littermate female kittens were randomly assigned to one of the following treatment groups within the first 24 h of birth: testosterone enanthate 12.5 mg sc (TE; n = 8) or Placebo (PL; n = 5). The animals were subsequently assessed for fecal sexual hormones until puberty was attained and subsequently when matings occurred. After 21 days, ovulation and gestation were diagnosed. All queens were subsequently ovario-hysterectomized. Fecal testosterone concentrations differed between the treatment groups throughout the study period (P 0.1). While all the females were receptive during the pubertal estrus (P > 0.1), two TE (2/8) compared with all (5/5) females of the PL group had ovulations (P < 0.05). Only one (1/2) compared with three (3/5) of the queens of the TE and PL groups, respectively became pregnant. All kittens of the TE group had transient clitoral enlargement. Anovulatory TE-treated cats had no corpus luteum, and a significant diminution of the endometrial glands as well as of the height of the uterine epithelium. It is concluded that, in domestic cats, a single postnatal supra-physiological dose of testosterone caused a large proportion of queens to be anovulatory and there were also histological endometrial abnormalities that also occurred with this treatment that were accompanied by mild and transient side effects.Fil: Demalde, Lucia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; ArgentinaFil: López Merlo, Mariana Lucía. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Vercellini, Maria del Rosario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; ArgentinaFil: Barbeito, Claudio Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Fernandez, Patricia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; ArgentinaFil: Gobello, María Cristina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Laboratorio de Nutrición Mineral y Fisiología Reproductiva; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Hypothesis of the basic biological sense of cancer revisited: a putative explanation of Peto's paradox

The conventional interpretation of cancer, summarized in the unified genetic theory of carcinogenesis, assumes that the malignant cell is the anatomical and physiological unit of cancer. This assumption means that any evolutionary increase in the number of cells (and thus body size) should lead to a higher tumor incidence since the population at risk is higher. However, the available data fail to support this prediction: most animals, in particular most mammals, exhibiting wide differences in body size and lifespan, from the mouse to the blue whale, display a roughly similar tumor incidence. This unexpected lack of correlation between body size, lifespan and cancer is usually called Peto?s paradox and it has intrigued theoretical oncologists for decades.In this essay, we attempt to offer a putative explanation of this paradox based on the notion that the unit at risk of carcinogenesis is actually the tissue or organ rather than the individual cell. In turn, this notion is based on a different interpretation of neoplastic diseases that we proposed some years ago and that has been called the hypothesis of the biological sense of cancer. This hypothesis was based on the observation that throughout the animal kingdom, cancer seems to arise only in organs and tissues (or parts of them) that have experienced a significant decrease in the regenerative ability, and this would occur when a critical proportion of their cells have partially or wholly lost that capacity. In such a case, if an organism or an organ were x times larger than another one, the probability that its regenerative capacity is critically diminished would be x times lower, because an x times greater number of cells would have to be affected to depress that capacity. This lower probability would balance the proportionally higher number of their cells that could be transformed and this would explain why the blue whale displays no greater risk of developing cancer than the mouse by unit of time. However, since big animals tend to live y times longer than small ones, it remains to explain why both animals may display a similar tumor incidence by lifespan. The concept of mass-specific basal metabolic rate (msBMR) can account for this problem since msBMR diminishes with body weight as much as lifespan increases meaning that the time for individual cells to get both the natural decline in regenerative ability and potential neoplastic mutations should be, in the big animal, y times slower than in the small one. This could explain why the tumor incidence in blue whales along their long lifespan may be not higher than that observed in mice along their short life.Fil: Bustuoabad, Oscar David. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Ruggiero, Raul Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentin

Anatomy of hypothalamic and diencephalic nuclei involved in seasonal fertility regulation in ewes

In this study, we describe in detail the anatomy of nuclei involved in seasonal fertility regulation (SFR) in ewes. For this purpose, the intergeniculate leaflet of the visual thalamus, the caudal hypothalamic arcuate nucleus, and suprachiasmatic, paraventricular and supraoptic nuclei of the rostral hypothalamus were morphometrically and qualitatively analyzed in Nissl-stained serial sections, in the three anatomical planes. In addition, data were collected on calcium-binding proteins and cell phenotypes after immunostaining alternate serial sections for calretinin, parvalbumin and calbindin. For a complete neuroanatomical study, glial architecture was assessed by immunostaining and analyzing alternate sections for glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (IBA1). The results showed a strong microglial and astroglia reaction around the hypothalamic nuclei of interest and around the whole 3rd ventricle of the ewe brain. Moreover, we correlated cytoarchitectonic coordinates of panoramic serial sections with their macroscopic localization and extension in midline sagittal-sectioned whole brain to provide guidelines for microdissecting nuclei involved in SFR

Magnetic resonance imaging evaluation of Yukatan minipig brains for neurotherapy applications

Magnetic resonance imaging (MRI) of six Yukatan minipig brains was performed. The animals were placed in stereotaxic conditions currently used in experiments. To allow for correctpositioning of the animal in the MRI instrument, landmarks were previously traced on the snout of the pig. To avoid movements, animal were anesthetized. The animals were placed in a prone position in a Siemens Magnetom Avanto 1.5 System with a head coil. Axial T2-weighted and sagittal T1-weighted MRI images were obtained from each pig. Afterwards, the brains of the pigs were fixed and cut into axial sections. Histologic and MR images were compared. The usefulness of this technique is discussed

Evo-devo of human adolescence: beyond disease models of early puberty

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research