Current and predicted temperatures impair reproduction in the Australian sheep flock

Climate change threatens global livestock production1,2. We modelled the impact of recent temperatures and a 1°C and 3°C temperature increase over the historical baseline on risks of heat stress at key periods of the reproductive cycle and consequences for reproduction across the entire Australian sheep flock. We estimate that 2.1 million potential lambs are currently lost annually due to heat stress, increasing to 2.5 and 3.3 million as temperatures rise.

Dynamics of Neospora caninum-Associated Abortions in A Dairy Sheep Flock and Results of a Test-and-Cull Control Programme

Neospora caninum is an apicomplexan parasite that can cause abortions and perinatal mortality in sheep. Although ovine neosporosis has been described worldwide, there is a lack of information about the relationship between N. caninum serostatus and the reproductive performance. In this study, we described the infection dynamics in a dairy sheep flock with an abortion rate up to 25% and a N. caninum seroprevalence of 32%. Abortions were recorded in 36% and 9% of seropositive and seronegative sheep, respectively. Seropositive sheep were more likely to abort twice (OR = 4.44) or three or more times (OR = 10.13) than seronegative sheep. Endogenous transplacental transmission was the main route of transmission since 86% of seropositive sheep had seropositive offspring. Within dams that had any abortion, seropositive sheep were more likely than seronegative ones to have female descendants that aborted (OR = 8.12). The slight increase in seropositivity with the age, the low percentage of animals with postnatal seroconversion or with low avidity antibodies, and the seropositivity of one flock dog, indicated that horizontal transmission might have some relevance in this flock. A control programme based on selective culling of seropositive sheep and replacement with seronegative animals was effective in reducing the abortion rate to 7.2%.

Subclinical mastitis in a pampinta dairy sheep flock in the la pampa province

Se han estudiado aspectos de la oveja Pampinta, una raza sintética desarrollada en la EEA de Anguil, constituida por Frisona del Este (East Friesian) y Corriedale. Es considerada de triple propósito (carne, leche y lana), pero seleccionada fenotípicamente hacia la raza Frisona del Este, siendo una de las principales razas que se la utiliza en ordeñe en Argentina. El objetivo de este trabajo es describir las mastitis subclínicas (MSC) que ocurren en la majada del Tambo Modelo de la Experimental de Anguil, con datos recogidos en los controles lecheros entre los años 2009 y 2014. Se utilizó un modelo animal con efectos aleatorios y efectos fijos como edad al parto; año de lactancia; tipo de cría y parto y clase de producción lechera. Se utilizó el programa estadístico SAS para los datos de producción y un Threshold Model (TM, Legarra et al., 2008) para mastitis. La producción de leche no estuvo relacionada con la incidencia de mastitis. El recuento de células somáticas (RCS) varía a lo largo de la lactancia, teniendo valores elevados al comienzo, luego desciende y se mantiene. La edad, la presencia de MSC y el nivel de producción de leche son factores que influyen en el RCS. El ambiente donde se encuentren lo animales puede tener factores estresantes que pueden interferir en el sistema inmunológico. Se necesitan más estudios y en otros establecimientos para poder generalizar estos resultados, lo que si hay que tener en cuenta que existe una demanda en los procesos de selección.

Meningoencephalitis, Vasculitis, and Abortions Caused by Chlamydia pecorum in a Herd of Cattle

A cow dairy ( n = 2000) in close proximity to a sheep flock had third-trimester abortions and fatalities in cows and calves over a 14-month period. Eighteen of 33 aborted fetuses (55%) had multifocal random suppurative or mononuclear meningoencephalitis with vasculitis. Seventeen of these affected fetuses had intracytoplasmic bacteria in endothelial cells, and 1 fetus with pericarditis had similar bacteria within mesothelial cells or macrophages. Immunohistochemistry for Chlamydia spp. or polymerase chain reaction (PCR) for Chlamydia pecorum or both, performed on brain or pooled tissue, were positive in all 14 tested fetuses that had meningoencephalitis and in 4/4 calves and in 3/4 tested cows that had meningoencephalitis and thrombotic vasculitis. In 1 calf and 11/11 fetuses, C. pecorum PCR amplicon sequences were 100% homologous to published C. pecorum sequences. Enzootic chlamydiosis due to C. pecorum was the identified cause of the late term abortions and the vasculitis and meningoencephalitis in fetuses, calves, and cows. C. pecorum, an uncommon bovine abortogenic agent, is a differential diagnosis in late-term aborted fetuses with meningoencephalitis, vasculitis, and polyserositis.

Environmental Factors Affecting Birth Weight And Litter Size In Yankasa Sheep

Records on 1634 lambings of a Yankasa sheep flock collected from 1983 to 1990 were used to determine the effects of parity, litter size, sex, season and year of birth on birth weight, and that of parity, season and year of birth on litter size respectively. Least squares means (± s.e.) for birth weight and litter size were 2.49±0.013kg and 1.22±0.010 respectively. Birth weight was significantly (P<0.01) affected by parity, sex, litter size and season of birth. Lambs born in the late wet season had higher birth weights than those born in other seasons. Also, male and single lambs were heavier at birth than female and twin lambs. Litter size was significantly (P<0.01) affected by parity, season and year of birth. Late wet season lambing had lower litter size than other seasons. The repeatability estimates for birth weight and litter size were 0.19±0.028 and 0.01±0.032 respectively while phenotypic correlation between the two traits was -0.249.

Index selection of Kazakh karakul sur-type sheep with platinum shades

Aim of the study: Karakul sheep farming is one of the effective subsectors of animal breeding in the southwestern region of Kazakhstan. Sheep coloring is a result of genetic factors. Breeding can provide farmers with offspring of the desired color through the selection of parental couples. Materials: This research introduces an index method for breeding sur-type sheep with the proportion of underfur fibers under 25%. Such a proportion of underfur fibers provides a 15.25% deeper color within the breed at the 25.3% higher chance of getting platinum shades. Methods: Platinum coloring in sheep makes them less piebald. The inheritance index is quite stable and is within 55.66-65.66%. In the breeding flock, the initial proportion of sur-type lambs which could be used in coat making (elite class) was up to 8.72%. The analysis of platinum color heritability by Kazakh sur-type karakul sheep shows that this color is inherited as a dominant one in the line breeding. The share of sur-type sheep with platinum shades was between 85.85% and 87.27%. Results: The difference in the inherited trait between the groups of sheep selected according to the proportion of underfur fibers was insignificant, 0.99-1.42% (P > 0.05). The stabilizing selection introduced into the theory of line breeding of Kazakh sur-type sheep allowed optimizing the variability of selected features to the level of desired parameters. The authors have proposed the index selection method for sur-type sheep breeding that can be applied to improve the Atyrau sheep flock, to increase their genetic potential, and to apply various line breeding levels to accelerate the breeding process. Conclusions: The originally designed method for improving breeding indexes will be useful when setting optimal breeding goals (fur color and quality) and assessing genetic parameters of a certain sheep flock. The study was approved by the Ethics Committee attached to the Far Eastern State Agrarian University (Protocol No. 5 of 25 May 2010).