Observations on the occurrence of crystal-like structures in nematode parasites of sheep and cattle

Waller P. J., Dash K. M. and Major G. W. 1979. Observations on the Occurrence of crystal-like structures in nematode parasites of sheep and cattle. Internationl Journal for Parasitology9: 147–151. Intracellular rod-like inclusions were found in a high percentage of inhibited fourth-stage larvae of H. contortus in sheep with naturally acquired infections. Artificial infections showed inclusions occurred in developing as well as inhibited fourth-stage larvae. The presence of these structures was associated with degenerative changes of the parasites and serial worm counts showed that larvae with large numbers of inclusions failed to persist within the host.Large refractive hexagonal crystals were observed in the gut lumen of fourth-stage and adult O. ostertagi acquired by previously worm-free lambs grazed on cattle pastures. The crystals tended to accumulate in the posterior gut region where they may cause gut blockage and lead to early mortality of the parasites in the abnormal host. No inclusions or crystals were observed in O. ostertagi from cattle or goats, or in O. circumcincta from sheep.     

On synchronous sporulation with possible reference to malarial parasites

With the view of suggesting a possible mechanism, it is shown that sporulation may be synchronous, as with the malarial parasite, given the following condition: A metabolite which is essential to the growth of the parasite is periodically released from storage organs and dissipated from the blood stream of the host.     

Physiological responses to stress with reference to the domestic fowl.

Environmental stress may effect the outcome of routine investigations as well as experimental procedures. This is illustrated by investigations in the domestic fowl.     

Helminth parasites of intermingling axis deer, wild swine and domestic cattle from the island of Molokai, Hawaii

Helminth infections of axis deer (Cervus axis), wild swine (Sus scrofa) and domestic cattle (Bos taurus) were studied among intermingling herds on the Puu-O-Hoku Ranch, Molokai, Hawaii. Twenty-four species of helminths were collected from the 10 deer, 10 swine and 10 cattle. Capillaria bovis, Cooperia punctata, Haemonchus contortus and Trichostrongylus axei infected both axis deer and cattle, whereas Gongylonema pulchrum infected both axis deer and wild swine. None of the species of helminths occurred in both wild swine and cattle nor was any species found in all three hosts. Wild swine and domestic cattle supported separate and distinct helminth communities. In contrast, the helminth community of axis deer appeared to be derived from the helminth communities of cattle and wild swine and consisted only of those species capable of parasitizing either a broad range of ruminants or many mammalian taxa.     

Environmental temperature and lactation (with special reference to cattle)

The majority of fundamental information on temperature effects on lactation is on cattle. The yield and composition of milk are affected by the temperature of the environment or the animal's body temperature. Environmental temperatures lower and higher than the comfort zone temperatures, diminish yield and alter many of the components of milk. Concepts as to the possible manner in which temperature may alter the synthesis of milk and the role of the neuro-endocrine and environmental physiological funtions in the maintenance of lactation were presented. The elucidation of many of these postulated mechanisms of temperature effect on lactation merely awaits the application of available modern endocrine, physiological, and biochemical techniques utilizing chromatography, tracer, fluorometric, manometric, and other procedures.

---

Zusammenfassung Der Hauptteil der grundsÄtzlichen Kenntnisse über Einflüsse der Temperatur auf die Milcherzeugung betrifft Rinder. Die Milchleistung und Zusammensetzung der Milch werden von der Temperatur der Umgebung sowie im Tier beeinflusst. Temperaturen der Umgebung, die höher oder tiefer sind als die des normalen körperlichen Wohlbefindens, verringern die Michleistung und verÄndern die Zusammensetzung der Milch. Die verschiedenen Arten der VerÄnderung der Milchsynthese durch Temperaturunterschiede und die Rolle der neuro-endokrinen und anderen physiologischen Funktionen zur Unterstützung der Milcherzeugung werden dargestellt-Die AufklÄrung vieler dieser angenommenen Mechanismen des Temperatureinflusses auf die Milchproduktion verlangt lediglich die Anwendung der üblichen modernen Methoden der Hormonforschung, der Physiologie und Biochemie.

---

Resume La majeure partie des recherches faites sur l'influence exercée par la température sur la lactation concerne les bovidés. La quantité et la composition du lait son influencées par la température ambiante ou par celle du corps de l'animal. Des températures extérieures supérieures ou inférieures à celles limitant la zone de confort diminuent les quantités de lait sécrété et modifient plusieurs de ses composants. On indique ici les différentes possibilités d'action de la température sur la sythèse du lait et le rÔle que jouent les fonctions physiologiques, en particulier neuroendocrines sur le maintient de la lactation. L'établissement de bien des mecanismes supposés de l'influence de la température sur la production laitière nécessite l'utilisation des techniques modernes en physiologie et en biochimie ainsi que dans la recherche des hormones. Il s'agit en particulier de la Chromatographie,de la chimie, de la mesure de la fluorescence, des mesures de pression, etc.

     

Genetics and domestic cattle origins

Genetics has the potential to provide a novel layer of information pertaining to the origins and relationships of domestic cattle. While it is important not to overstate the power of archeological inference from genetic data, some previously widespread conjectures are inevitably contradicted with the addition of new information. Conjectures regarding domesticated cattle that fall into this category include a single domestication event with the development of Bos indicus breeds from earlier Bos taurus domesticates; the domestication of a third type of cattle in Africa having an intermediate morphology between the two taxa; and the special status of the Jersey breed as a European type with some exotic influences. In reality, a wideranging survey of the genetic variation of modern cattle reveals that they all derive from either zebu or taurine progenitors or are hybrids of the two. The quantitative divergence between Bos indicus and Bos taurus strongly supports a predomestic separation; that between African and European taurines also suggests genetic input from native aurochsen populations on each continent. Patterns of genetic variants assayed from paternally, maternally, and biparentally inherited genetic systems reveal that extensive hybridization of the two subspecies is part of the ancestry of Northern Indian, peripheral European, and almost all African cattle breeds. In Africa, which is the most extensive hybrid zone, the sexual asymmetry of the process of zebu introgression into native taurine breeds is strikingly evident. © 1998 Wiley-Liss, Inc.     

Genetically resistant sheep avoid parasites to a greater extent than do susceptible sheep

Livestock breeding programmes have created resistant (R) and susceptible (S) sheep that differ in their ability to control parasites through their immune function but potentially also their grazing behaviour (i.e. parasite avoidance). Using the Perendale genetic lines, we tested the hypothesis that R-sheep avoid parasites more effectively, reducing their parasite exposure/challenge, compared with S-sheep. However, in grazing systems, parasite-rich areas are also forage rich, suggesting that parasite avoidance behaviours are associated with nutritional penalties. We first created a naturally heterogeneous sward structure of gaps and tussocks and then used focal behavioural observations to quantify the sward selection of R- and S-sheep. Tussock swards were more nitrogen rich (41%), offered increased forage intake rates (32%) and contained 17 times more parasite larvae than gap swards. All the animals avoided grazing the tussock swards. However, the R-sheep grazed the tussock swards to a lesser degree than the S-sheep. We conclude that selection for genetic resistance has resulted in animals that, despite being well armed to fight parasitism through improved immune function, adopt parasite avoidance strategies with associated nutritional disadvantages. This experiment highlights the role of host behaviour in the control of parasitism and suggests that animals can be bred to avoid disease.     

Breeding cattle and sheep for resistance to gastrointestinal nematodes

Gastrointestinal nematodes are an important cause of reduced production of meat, milk and wool in domestic livestock. It is generally believed that problems caused by these parasites have increased owing to the intensification of animal husbandry(1-3) of resistance to anthelmintics, current research is focussed on alternative control strategies that do not rely on anthelmintics. Here, Bram Kloosterman, Henk Parmentier and Harm Ploeger review work on the genetic resistance of domestic ruminants to these nematodes and discuss the practicality of breeding programmes.     

Population response of reintroduced bighorn sheep after observed commingling with domestic sheep

Bighorn sheep (Ovis canadensis) often die from respiratory disease after commingling with domestic sheep. From 2000 to 2009, we observed commingling between domestic and reintroduced bighorn sheep in 3 populations in UT, USA. We investigated how commingling affected survival of radio-collared female bighorns that were released initially (founder) and those that were subsequently released (augmented). We predicted that the proportion of young surviving to their first winter and population growth would be lower after observed commingling with domestic sheep. We observed groups of bighorns year-round on 2,712 occasions and commingling between domestic sheep and bighorns in 6 instances. On Mount Timpanogos, survival rates were best modeled as constant for females (n?=?57) before and after observed commingling with domestic sheep. Survival rates of female bighorns, however, decreased significantly in Rock Canyon (n?=?21) and on Mount Nebo (n?=?22) for founder, but not augmented bighorns after observed commingling with domestic sheep. Also, the proportion of young surviving to their first winter was almost 3 times lower and population growth was reduced for bighorns after observed commingling with domestic sheep in Rock Canyon and on Mount Nebo. Commingling between domestic and bighorn sheep reduced population parameters in 2 of 3 bighorn populations we studied; however, on Mount Timpanogos, interactions between those 2 species were not fatal for radio-collared female bighorns. Wildlife biologists should manage for spatial separation of these 2 species and consider the location of hobby farms and trailing operations of domestic sheep near release sites for bighorns.     

The prevalence and intensity of external parasites in domestic pigeons (Columba livia domestica) in Egypt with special reference to the role of deltamethrin as insecticidal agent

This study aimed to investigate the prevalence and intensity of external parasites in domestic pigeons in Giza, Egypt, from January 2020 to December 2020. A total of 300 domestic pigeons (25 pigeons per month) were examined. The birds were divided into groups based on their age. The oxidative stress parameters; serum zinc concentration, serum malondialdehyde (MDA), and serum Nitric oxide were evaluated in single and mixed external parasitic infestations. The prevalence of external parasites in examined pigeons was 80.3%. The detected parasites were Pseudolynchia canariensis (P. canariensis), Hippobosca equina (H. equina), Columbicola columbae (C. columbae), Menopon gallinae (M. gallinae), Knemidocoptes species (spp.) and Dermanyssus gallinae (D. gallinae); their incidences were 41.6, 26, 7, 5,0.33 and 0.33%, respectively. The highest infestation was recorded in both spring and summer. . The incidence of disease was higher in squabs and young birds than in adults. The mixed external parasitic infestation was recorded in this study. The infected birds showed decreased serum zinc concentration and elevated MDA and serum Nitric oxide levels. In conclusion, regular monthly treatment with deltamethrin is recommended as an effective drug in the treatment of the infested birds and succeeded in reducing the incidence of externalparasites in the treated birds; in addition, pigeon management measures must be implemented to reduce the risk of external parasites.