Sexual differentiation in litter-bearing mammals: influence of sex of adjacent fetuses in utero

In rodents and swine, individual differences in a broad range of characteristics correlate with intrauterine position during fetal life. By identifying the intrauterine position of mice at cesarean delivery, we can predict reliably postnatal reproductive traits such as genital morphology, timing of puberty, length of estrous cycles, timing of reproductive senescence, sexual attractiveness, sexual behavior, aggressiveness, daily activity level, body weight and tissue enzyme activity in females; in males we can predict genital and brain morphology, sexual behavior, aggressiveness, daily activity level, body weight, and tissue enzyme activity. In mice, as in all mammals, male fetuses have greater concentrations of testosterone than do females. In addition, female mouse fetuses have greater circulating concentrations of estradiol than do male fetuses, a condition not found in all mammals. A mouse fetus positioned between males has greater concentrations of testosterone than does a fetus of the same sex positioned between females, and a fetus positioned between females has greater concentrations of estradiol than does a fetus of the same sex positioned between males. Gonadal steroids regulate differentiation of secondary sexual characteristics. Studies in which the effects of intrauterine position have been eliminated by exposing fetuses to steroid receptor blockers reveal the critical role of steroids in mediating this phenomenon. The intrauterine position phenomenon provides the only mammalian model for relating postnatal traits to concentrations of endogenous hormones to which individuals are exposed during fetal life. Results from studies using this naturally occurring experimental system in litter-bearing species have given insights concerning the consequences of individual differences in steroid concentrations during sexual differentiation that likely apply to all mammals. One specific hypothesis is that circulating estradiol may interact with testosterone in mediating some aspects of sexual differentiation in rodents and, thus, possibly in other mammals.     

Coordination of social signals and ovarian function during sexual development

Social cues, often in the form of priming pheromones, can retard or enhance the rate of sexual development in a variety of mammals. The complex interactions between the social environment and reproduction have been explored most thoroughly in the house mouse. A urinary pheromone produced by females in a group inhibits sexual development, and a urinary pheromone from adult males accelerates onset of puberty in juvenile females. These priming pheromones apparently are detected by the vomeronasal organ and induce the changes in ovarian function via changes in the hypothalamic-pituitary system. Accelerated onset of puberty is not accompanied by deficits in reproductive performance. Puberty acceleration can have important management implications for domestic farm animals. It already is proving useful for manipulation in rearing swine and in synchronizing seasonal reproductive recrudescence in sheep. In cattle, the results are less clear that signals from the bull can hasten onset of puberty in heifers. The effect may be operable only under certain nutritional or other interacting conditions. Presumably, the postpartum anestrus period in the cow can be shortened by stimulation from the bull, although pheromones have not been implicated in this effect.     

Identification of genomic regions that exhibit sexual dimorphism for size and muscularity in cattle

Sexual dimorphism, the phenomenon whereby males and females of the same species are distinctive in some aspect of appearance or size, has previously been documented in cattle for traits such as growth rate and carcass merit using a quantitative genetics approach. No previous study in cattle has attempted to document sexual dimorphism at a genome level; therefore, the objective of the present study was to determine whether genomic regions associated with size and muscularity in cattle exhibited signs of sexual dimorphism. Analyses were undertaken on 10 linear-type traits that describe the muscular and skeletal characteristics of both males and females of five beef cattle breeds: 1,444 Angus (AA), 6,433 Charolais (CH), 1,129 Hereford, 8,745 Limousin (LM), and 1,698 Simmental. Genome-wide association analyses were undertaken using imputed whole-genome sequence data for each sex separately by breed. For each single-nucleotide polymorphism (SNP) that was segregating in both sexes, the difference between the allele substitution effect sizes for each sex, in each breed separately, was calculated. Suggestively (P ≤ 1 × 10⁻⁵) sexually dimorphic SNPs that were segregating in both males and females were detected for all traits in all breeds, although the location of these SNPs differed by both trait and breed. Significantly (P ≤ 1 × 10⁻⁸) dimorphic SNPs were detected in just three traits in the AA, seven traits in the CH, and three traits in the LM. The vast majority of all segregating autosomal SNPs (86% in AA to 94% in LM) had the same minor allele in both males and females. Differences (P ≤ 0.05) in allele frequencies between the sexes were observed for between 36% (LM) and 66% (AA) of the total autosomal SNPs that were segregating in both sexes. Dimorphic SNPs were located within a number of genes related to muscularity and/or size including the NAB1, COL5A2, and IWS1 genes on BTA2 that are located close to, and thought to be co-inherited with, the MSTN gene. Overall, sexual dimorphism exists in cattle at the genome level, but it is not consistent by either trait or breed.     

Seasonality of Reproduction in Mammals: Intimate Regulatory Mechanisms and Practical Implications

Farm mammals generally express seasonal variations in their production traits, thus inducing changing availability of fresh derived animal products (meat, milk and cheese) or performances (horses). This is due to a more or less marked seasonal birth distribution in sheep and goats, in horses but not cattle. Birth peak occurs at the end of winter-early spring, the most favourable period for the progeny to survive. Most species show seasonal variations in their ovulation frequency (presence or absence of ovulation), spermatogenic activity (from moderate decrease to complete absence of sperm production), gamete quality (variations in fertilization rates and embryo survival), and also sexual behaviour. The intimate mechanism involved is a complex combination of endogenous circannual rhythm driven and synchronized by light and melatonin. Profound and long-term neuroendocrine changes involving different neuromediator systems were described to play a role in these processes. In most species artificial photoperiodic treatments consisting of extra-light during natural short days (in sheep and goats and mares) or melatonin during long days (in sheep and goats) are extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres. Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non-invasive ones which fully respect animal welfare. Genetic selection could be one of the future ways to decrease seasonality in sheep and goats.     

Interspecific variation in wildlife responses to cattle,swine and chicken feed in the forests surrounding poultry farms

To strengthen farm biosecurity, wildlife behaviors around livestock environments require significant attention. Livestock feed is considered one of essential factors that attract wildlife to the livestock environment. We experimentally studied wildlife response to cattle, swine, and chicken concentrated feeds in the forests surrounding poultry farms. In 14 feeding sites, four feed conditions were established: without feed (control); cattle feed; chicken feed; and swine feed. Wildlife behaviors at each feed point were monitored using infrared cameras. In 3,175 videos, 10 mammals were photographed on 10 or more occasions. Wildlife more frequently appeared at the points with feed than without feed. In addition, the number of videos that captured foraging or interest behaviors was largest for swine feed, followed by chicken feed, then cattle feed. There was a large difference among wildlife in their response to livestock feeds, although each species did not have a strong preference for a specific feed. Livestock feeds invite frequent visits by high and moderate response groups, especially omnivores and carnivores with omnivorous tendencies. Therefore, to protect against such wildlife intrusion, leftover feed and feed storage must be properly managed. This study also suggests that livestock feeds may not cause intrusions by rare response group species; hence, if their intrusions occur, they may be due to factors other than livestock feed. The study situation can partly reflect actual feed-stealing situations. The results will contribute to consider the properly management to protect livestock environments from wildlife intrusions.     

Selection for disease resistance in domestic ruminants and swine by indicator traits as well as marker and causal genes--a review. Part 1: Short introduction to immunogenetics of MHC and non-MHC genes and special immunogenetics of cattle and swine

The introduction deals with immunogenetic investigations on the field of life-stock. The main chapter is outlined as a tabular overview of current opportunities of the application of indicator traits as well as marker and causal genes in breeding for disease resistance in cattle, sheep, goats and swine. In the discussion of the second part, emphasis was layed on diseases of small ruminants in central and western Europe. Indicator traits are discussed with respect of their advantages and disadvantages. The rigorous selection of specific traits is connected with an increase of the number of homozygotes. In contrary, pathogens do undergo mutations, thus escaping the host's immune system. Out of this point of view it is advisable, to set on selection very cautiously. The role of technologies of modern immunogenetics is pointed out in respect of constructing disease resistant animals.     

Selection for disease and epidemic resistance in domestic ruminants and swine by indicator traits,marker and causal genes--a review. Part 2: Special immunogenetics of sheep and goats with particular regard for endoparasitoses,scrapie, foot rot and maedi-visna virus infection

The introduction of the first part deals with immunogenetic investigations on the field of life-stock. The main chapter is outlined as a tabular overview of current opportunities of the application of indicator traits as well as marker and causal genes in breeding for disease resistance in cattle, sheep, goats and swine. In the discussion of the second part, emphasis was laied on diseases of small ruminants in central and western Europe with special respect of endoparasitoses, scrapie, foot-rot and maedi-visna virus infection. Indicator traits are discussed with respect of their advantages and disadvantages. The rigorous selection on specific traits is connected with an increase of the number of homozygotes. In contrary, pathogens do undergo mutations, thus escaping the host's immune system. Out of this point of view it is advisable, to set on selection very cautiously. The role of technologies of modern immunogenetics is pointed out in respect of constructing disease resistant animals.     

Responses of cattle, sheep and poultry to a recombinant vaccinia virus expressing a swine influenza haemagglutinin

Groups of cattle, sheep and poultry were inoculated with a recombinant vaccinia virus expressing the haemagglutinin of the swine influenza virus A/NJ/11/76. No adverse clinical responses were recorded and none of the animals developed a viraemia when inoculated with the recombinant or wild-type vaccinia virus. Recombinant virus reisolated from lesions in cattle was stable, maintaining its thymidine kinase negative phenotype and ability to express the swine influenza haemagglutinin. Antibodies to the influenza haemagglutinin were detected in cattle, sheep and poultry inoculated with the recombinant virus. While no animals inoculated with wild-type virus developed these antibodies, there was no detectable spread of either recombinant or wild-type virus from the inoculation sites or to in-contact uninoculated animals. The results indicate that recombinant vaccinia viruses can induce immune responses in cattle, sheep and poultry demonstrating their potential as vaccine vectors in a variety of important veterinary species.     

Are goats naturally resistant to gastric Helicobacter infection?

Gastric Helicobacter species are widespread and have been reported in wild and domestic mammals of different dietary habits such as humans, dogs, cats, macaques, mice, cheetahs, ferrets, swine and cattle. All have been associated with gastric pathologies. Recently, gastric Helicobacter species were shown to be widespread in cattle and swine in Europe, and there is a report of Helicobacter pylori in sheep in Italy. However, there are no reports of Helicobacter infection in the goat, another important domestic animal of human consumption. The aim of our study was to assess whether Helicobacter abomasal infection was common in goats slaughtered for human consumption. Infection was detected through PCR analysis of DNA extracted from gastric biopsies, using genus- and species-specific primers. Bovine and porcine gastric samples were also analyzed as positive controls. None of the 70 goats were positive for Helicobacter spp.; however, Candidatus Helicobacter bovis and Candidatus Helicobacter suis were detected in 85% of the bovine and 45% of the porcine samples, respectively. We discuss the possibility that goats may exhibit natural resistance to abomasal infection by Helicobacter spp.     

Comparative activities of semicarbazide-sensitive amine oxidase (SSAO) in five domestic species

Semicarbazide-sensitive amine oxidase (SSAO) activity was measured spectrophotometrically using benzylamine as a substrate, in the serum of healthy males and females of horses, camels, cattle, sheep and goats. The animals were born and raised in the same area, and the blood collection was made on the same day to avoid variations. Also the concentrations of protein and copper were measured in the same samples. There were no significant gender-related differences in SSAO activity between the tested animals regardless of species. Activities of SSAO in either male or female of horse were significantly different (p < 0.05) from the remaining tested animals. The highest activities (expressed as micromole of benzaldehyde production/mg protein/hr) were found in horses (9.592 and 9.458), followed by camels (3.226 and 2.407), cattle (1.014 and 1.648), goat (0.750 and 0.572) and sheep (0.435 and 0.244). Insignificant higher activities of SSAO were noted in all males of the tested animals compared to that in females except in cattle. The results suggest that horses are endowed with a very high activity of this enzyme amounting to 3-21 times higher than that found in large and small ruminants. There were no significant differences between the levels of protein and copper in either sex of all the tested species.     

Mechanisms of infection in the respiratory tract

Related to its potential vulnerability the respiratory tract has a very complex and effective defence apparatus. The interaction between these defence mechanisms and certain characteristics of aetiological agents results in a pattern in which initial infections by these agents tend to occur at specific sites in the tract. Infections in which the primary portal of entry is in the upper respiratory tract include Bordetella bronchiseptica and Haemophilus spp in pigs; Pasteurella spp in cattle, sheep, pigs; Mycoplasma spp in cattle, sheep, pigs and poultry; equine herpesvirus 1 in horses; infectious bovine rhinotracheitis in cattle; parainfluenza 3 in cattle and sheep; infectious laryngo-tracheitis and infectious bronchitis in poultry; feline viral rhinotracheitis and calicivirus in cats; Aujeszky's disease virus and swine influenza in pigs; and equine influenza in horses. Infections in which the primary portal of entry is in the lower respiratory tract include Aspergillus fumigatus in poultry and mammals, respiratory syncytial virus in cattle, distemper virus in dogs and adenovirus in cattle and dogs. A fuller understanding of the interactions between an agent and the host at the point of entry would make it much easier to develop effective vaccines and therapeutic agents.     

新疆塔里木盆地叶城沙蜥的两性异形

叶城沙蜥是一种主要分布于中国新疆南部地区的蜥蜴,通过测量和比较采自新疆塔里木盆地且末县叶城沙蜥的个体大小以及口宽等8个形态特征,研究了叶城沙蜥的两性异形。研究共采集叶城沙蜥62只,其中成年雌性个体27只,雄性个体35只。结果显示:(1)叶城沙蜥雌雄性成体的体长有显著差异,雄性大于雌性,表明叶城沙蜥具有雄性偏大的两性异形模式;(2)叶城沙蜥其他身体形态特征中尾长、腹长和头长3个特征有显著差异,其中雄性的尾长和头长大于雌性,而雌性的腹长大于雄性;(3)叶城沙蜥雌雄性个体间的口宽、眼间距等其他形态特征则没有显著差异。叶城沙蜥的两性异形表现为雄性大于雌性,并且雄性具有更大的头部和更长的尾部,雌性具有更长有腹部,这可能是雄性个体面临的性选择压力与雌性个体面临的繁殖压力共同作用的结果。     

Echinococcosis/hydatidosis in western Iran

In the present study, 115 stray dogs (56 males and 59 females, mixed breed), 86 golden jackal (Canis aureus, 42 males and 44 females), 60 red foxes (Vulpes vulpes, 33 males and 27 females), and three female wolves (Canis lupus) were examined for Echinococcus granulosus infection, as well as, 32,898 sheep, 10,691 goats, 15,779 cattle and 659 buffaloes for hydatid infection from five provinces in western Iran during 3 years (1997-2000). Meanwhile fertility rates of different types and forms of cysts isolated from infected animals and the viability of protoscolices were also determined. Results indicated that 19.1% of the dogs, 2.3% of the golden jackals and 5% of the red foxes were infected with Echinococcus granulosus. 11.1% of the sheep, 6.3% of the goats, 16.4% of the cattle and 12.4% of the buffaloes were also found to be infected with hydatid cyst. The cysts isolated from liver and lungs of the sheep show higher fertility rate than the cysts of liver and lungs of goats, cattle and buffaloes.     

Factors relating to urine spraying and fighting in prepubertally gonadectomized cats

The fact that male cats are routinely castrated prior to full sexual maturity for behavioral reasons prompted a survey of the prevalence of these behaviors in prepubertally gonadectomized male and female cats. About 10% of the 134 male and 5% of the 152 female cats studied engaged in spraying on a frequent basis later in adult life. Problem spraying and fighting in males was of the same order of magnitude as in males castrated in adulthood after the problem behaviors had appeared. The age of prepubertal castration, ranging from 6 to 10 months, had no influence on spraying or fighting later in life. It was found that male cats are more likely to spray and fight if they are in households with female cats than with other male cats. With regard to female cats, spraying or fighting was less than that of male cats. Age at the time of gonadectomy was not a factor in their tendency to spray or fight. Possible prenatal masculinization of female fetuses by male fetuses, as revealed by littermate composition, was not a factor in the predisposition of female cats to spray or fight.     

Variations in the normal activity of esterases in plasma and liver of camels (Camelus dromedarius), cattle (Bos indicus), sheep (Ovis aries) and goats (Capra hircus)

Esterases are a large group of enzymes found in plasma (or serum) and tissues, which hydrolyse a number of xenobiotics. Some of these enzymes have not yet been measured in tropical domestic animals. In the present work, we have measured the activities of three esterases, viz. aspirin esterase, cholinesterase and nitrophenylacetate esterase in the plasma and livers of male and female camels, cattle, sheep and goats. The results indicate that the enzyme activities are highest in the goat, followed by sheep and cattle (which showed broadly similar activities), and lowest in camels. Gender had no statistically significant effect, although males exhibited about 5-8% more enzyme activity in each of the four species, than females.     

New techniques to measure blood cholinesterase activity in domesticated animals.

A macromethod and a semimicromethod were developed to measure erythrocyte acetylcholinesterase activity in cattle, sheep, goats, horses, dogs, and swine, and to measure plasma cholinesterase activity in horses, dogs, and swine. Comparison of the 2 methods with erythrocytes of sheep, cattle, goats, and horses indicated both methods gave similar results. They can be done in a shorter time and are more sensitive than Michel's method. Normal deltapH values per minutes, with standard deviations for blood cholinesterase activity of animals of different ages, sexes, breeds, and species, were: 0.76 +/- 0.12/30; 0.65 +/- 0.10/15; 0.69 +/- 0.19/45; 0.78 +/- 0.11/45; 0.63 +/- 0.11/45; and 0.71 +/- 0.06/25 for sheep, cattle, goats, horses, dogs, and swine erythrocyte acetylcholinesterase, respectively; and 0.66 +/- 0.18/20; 0.67 +/- 0.20/30, and 0.46 +/- 0.05/60 for horses, dogs, and swine plasma cholinesterase, respectively. It was shown that either the chloride or the iodide salt of acetylcholine can be used as the enzyme substrate. tin blood samples stored at 5 C for 24 hours, there was no significant change of the enzymatic activity.     

Pestivirus infections in Norway. Serological investigations in cattle, sheep and pigs.

Serum samples from 1,133 dairy cows (187 herds), 3,712 ewes (103 flocks) and 1,317 adult pigs (877 herds), were tested for neutralizing antibodies against the NADL strain of bovine virus diarrhoea virus. The prevalence rate of seropositive animals was 18.5% in cattle, 4.5% in sheep and 2.2% in pigs, such seroreactors being found in 28% of the cattle herds and 18% of the sheep flocks. In all three species the rate showed considerable herd and geographical variation. In cattle the seroreactor rate was similar in herds with normal reproduction and in 62 herds with problems of repeat breeding. Of 31 pig sera containing antibodies against the NADL strain, 27 were also positive in a neutralization test for antibodies against swine fever virus (Baker strain). However, all sera showed a higher titre of antibodies against the bovine strain than against the swine fever virus. It was concluded that the immune response of the pigs had been induced by ruminant pestivirus, and not by swine fever virus.     

A 6-year survey of pathological conditions of slaughtered animals at Zango abattoir in Zaria,Kaduna State,Nigeria

A 6-year retrospective study (2000–2005) of animals slaughtered at the Zango abattoir in Zaria, Kaduna State, Nigeria was carried out to determine disease conditions encountered in slaughtered animals. Records kept at the abattoir were analysed. A total of 69,307 cattle, 3,820 goats and 1,763 sheep were slaughtered for the period under study. Of the 69,307 cattle slaughtered for the period, 22,459 (32.41%) were males and 46,848 (67.59%) were females, while 1,763 sheep were slaughtered comprising of 506 (28.70%) males and 1,257 (71.30%) females, and 3,820 goats made up of 1,212 (31.73%) males and 2,608 (68.27%) were females. The major disease and/or pathological conditions were helminthosis (fascioliasis, haemonchosis and paramphistomosis) 16.20%, Streptothricosis 4.15%, Pericarditis 2.20%, liver cirrhosis 2.08%, abscesses 1.04%, pneumonia 0.14%, nephritis 0.05% and Contagious Bovine Pleuropneumonia, Tuberculosis and Nocardiosis 0.01% each. Out of the 15,075 infected organs, 13,314 (88.38%) were partially salvaged while 1,751 (11.6%) whole organs were condemned. A total of 1,239 pregnant cows, 221 pregnant ewes and 637 pregnant does were slaughtered, representing a foetal wastage of 2.65% for cattle, 17.58% for sheep and 24.43% for goats. The result of this study apart from serving as an indicator of field disease condition also demonstrates cases of serious losses in production due to slaughter of pregnant animals especially for sheep and goats.     

Canine pedal dermatitis due to percutaneous Uncinaria stenocephala infection

Related to its potential vulnerability the respiratory tract has a very complex and effective defence apparatus. The interaction between these defence mechanisms and certain characteristics of aetiological agents results in a pattern in which initial infections by these agents tend to occur at specific sites in the tract.

Infections in which the primary portal of entry is in the upper respiratory tract include Bordetella bronchiseptica and Haemophilus spp in pigs; Pasteurella spp in cattle, sheep, pigs; Mycoplasma spp in cattle, sheep, pigs and poultry; equine herpesvirus 1 in horses; infectious bovine rhinotracheitis in cattle; parainfluenza 3 in cattle and sheep; infectious laryngo-tracheitis and infectious bronchitis in poultry; feline viral rhinotracheitis and calicivirus in cats; Aujeszky' disease virus and swine influenza in pigs; and equine influenza in horses. Infections in which the primary portal of entry is in the lower respiratory tract include Aspergillrrs fumigatus in poultry and mammals, respiratory syncytial virus in cattle, distemper virus in dogs and adenovirus in cattle and dogs. A fuller understanding of the interactions between an agent and the host at the point of entry would make it much easier to develop effective vaccines and therapeutic agents.