Maternal stress in sheep during late pregnancy influences sperm quality in early puberty of the offspring.

Stress at the end of sheep gestation can damage the reproductive development of young males. The aim of the present study was to evaluate the effects of LPS administration in the last third of sheep pregnancy on the reproductive parameters of prepubertal rams. Thirty-six pregnant nulliparous ewes (12 ±â€¯2 months old; 45 ±â€¯6 kg) were assigned to two treatments, LPS (E. coli; 0.8 µg kg-1) and control (placebo/saline) administered in late pregnancy (120 days post-conception). The animals gave birth to 17 male lambs (11 LPS; 8 control). Reproductive development of the young rams was analyzed from 5 to 12 months of age. A completely randomized design in double factorial scheme was used. The data were analyzed by analysis of variance. The model included treatment (LPS; control), age as main effects and their interactions, and the animal as a repeated measure. Means were compared by the PDIFF-SAS (Pr > |t|) at P < 0.05. An effect of age was observed for scrotal circumference, testicular consistency, homogeneity of testicular parenchyma, vascularization, semen quantity and quality, and blood testosterone concentration (P < 0.05). LPS increased sperm defects (P < 0.05) but an interaction with age was not observed (P > 0.05) with higher abnormalities only during months 8 and 9 (P < 0.05) and not thereafter. In summary, LPS did not cause long-term damage to testicular morphology analyzed from the onset of puberty to sexual maturity. However, LPS treatment affected sperm morphology during early puberty of the offspring.

Heat loss efficiency and HSPs gene expression of Nellore cows in tropical climate conditions.

Adaptation is a relevant characteristic to be understood in livestock animals in order to maintain and raise productivity. In Brazil, the Nellore beef cattle are widely disseminated and well-adapted breed that present good thermoregulatory characteristics for tropical environment conditions. Conversely, the physiological and cellular mechanisms required for thermoregulation and thermotolerance in this breed are still limited. The aim of this study was to comprehend the heat loss efficiency at the whole animal level and heat shock response at the cellular level of Nellore cows in tropical climate conditions. Healthy purebred Nellore cows were classified according to their capacity to lose body heat as Efficient or Inefficient based on vaginal temperature which was continuously monitored by data-loggers. Rectal, tail, and ocular temperatures, sweating rate, and respiratory frequency were collected to assess other thermoregulatory responses. Peripheral mononuclear cells were used for gene expression of heat shock proteins 60, 70, and 90 induced by in vitro heat treatments at 38, 40, and 42 °C. In our findings, the Efficient cows presented higher sweating rates compared to Inefficient cows that presented higher rectal temperature with greater amplitude of vaginal temperature profile. Transcription of the HSP genes was stable at 38 and 40 °C and decreased for all HSP genes at 42 °C. In conclusion, the Nellore efficiency to lose heat was mainly associated with their sweating capacity and cellular thermotolerance confirmed by the maintenance of heat shock proteins transcripts under heat stress. Taken together, this knowledge contributes as a future key for genetic selection of adapted animals.

Abrupt weaning type combined to stress during late pregnancy in sheep present economic losses on carcass and low testicular development in lambs

This study investigates the combined effect of the progressive or abrupt weaning after the stress during middle and late pregnancy on performance and development of lambs. Twenty-four male lambs were used, born from 18 Santa Ines ewes that were divided into three experimental groups. Pregnant ewes were submitted to the application of Lipolysaccharides E. coli (LPS) during the 70th day of pregnancy (Ig; n=12) or at the 120th day (Fg; n=8). Animals were kept as control (Cg; n=14). Lambs born in a 6 day interval were subjected to two types of weaning (Pw: progressive weaning; Aw: abrupt weaning at 45 days of age). Lamb data, including testicular development, yield carcass and economic cost were analyzed. Means were compared by F test and Student's t test (P0.05). The highest yields in gross margin was observed for the Cg group and the lowest for Fg (P0.05). On lambs’ testicular weight, Cg average value was higher than Fg (P0.05). The combined effect of LPS challenge as a simulated disease process during late pregnancy and abrupt weaning change the testicular weight and the yield carcass, resulting in economic losses.

Abrupt weaning type combined to stress during late pregnancy in sheep present economic losses on carcass and low testicular development in lambs

This study investigates the combined effect of the progressive or abrupt weaning after the stress during middle and late pregnancy on performance and development of lambs. Twenty-four male lambs were used, born from 18 Santa Ines ewes that were divided into three experimental groups. Pregnant ewes were submitted to the application of Lipolysaccharides E. coli (LPS) during the 70th day of pregnancy (Ig; n=12) or at the 120th day (Fg; n=8). Animals were kept as control (Cg; n=14). Lambs born in a 6 day interval were subjected to two types of weaning (Pw: progressive weaning; Aw: abrupt weaning at 45 days of age). Lamb data, including testicular development, yield carcass and economic cost were analyzed. Means were compared by F test and Student's t test (P<0.05). Fg lambs had the lowest average carcass weight compared with Cg and Fg groups (P<0.05) and lambs from progressive weaning had higher carcass weight in relation to the abrupt weaning process (P<0.05). On carcass yield, no difference was observed on gestation groups for any type of weaning (P>0.05). The highest yields in gross margin was observed for the Cg group and the lowest for Fg (P<0.05), and no difference to Ig group (P>0.05). On lambs testicular weight, Cg average value was higher than Fg (P<0.05), but no difference was observed on scrotal circumference (P>0.05). The combined effect of LPS challenge as a simulated disease process during late pregnancy and abrupt weaning change the testicular weight and the yield carcass, resulting in economic losses.(AU)

Termografia infravermelha da superfície ocular como indicador de estresse em suínos na fase de creche / Infrared thermography of the ocular surface as stress indicator for piglets postweaning

Desmama é uma fase crítica na vida do suíno devido a separação materna e a introdução de uma dieta seca. A termografia infravermelha medida na região ocular se mostra como um indicador confiável para a condição de estresse pontual de suínos. O objetivo deste estudo foi determinar a relação entre medidas de termografia infravermelha da superfície ocular e de cortisol em situações de estresse em leitões na pós desmama. Foram avaliados 66 leitões, uma vez por semana, durante sete semanas, em dois períodos do dia (7h e 15h) com medidas de temperatura superficial ocular, temperatura superficial do dorso e amostras de saliva para determinação de cortisol salivar. A análise estatística contemplou os efeitos fixos de semana e período do dia e sua interação e correlações de Pearson para relação entre termografia ocular, temperatura superficial e cortisol a 5% de significância. Cortisol salivar não diferiu entre os períodos, mas foi superior nas três primeiras semanas após o desmame (P<0,05). Nas duas primeiras semanas após a desmama o cortisol apresentou correlação alta e positiva (P<0,05) com a temperatura ocular máxima (0,89) e a temperatura superficial do dorso (0,80). As duas temperaturas superficiais apresentaram uma associação moderada positiva (r=0,41; P<0,0001) durante todo o período experimental. Este estudo destaca que a temperatura de superfície ocular obtida por meio da termografia infravermelha pode ser um indicador de temperatura de superfície corporal e estado de bem-estar de leitões em fase de creche, além de ser um método não invasivo e de rápida mensuração. Entretanto, mais pesquisas são necessárias para aprofundar a relação entre temperatura ocular e cortisol durante estresse crônico.(AU)

Weaning is a critical phase in pigs' life due to maternal separation and the introduction of a new diet. Infrared thermography measurement taken in the ocular region appears to be a reliable indicator of the stress condition of the pig. The aim of this study was to evaluate the relationship between ocular surface temperature by infrared thermography and cortisol in piglets post weaning. Sixty-six piglets were evaluated once a week, during 7 weeks, in two periods of the day (7am and 15pm) and ocular surface temperature and dorsal surface temperature were collected using a thermographic camera and a laser surface thermometer, respectively. Saliva was also collected to determine salivary cortisol. Statistical analysis included fixed effects of week and period of the day and their interaction, and relationship between thermography, dorsal surface temperature and cortisol were done by Pearson's correlations with 5% significance level. Salivary cortisol did not differ between periods, but it was higher in the first three weeks after weaning (P<0.05). During the first two weeks after weaning cortisol presented high and positive correlation (P<0.05) between ocular surface temperature (0.89) and dorsal surface temperature (0.80). The two superficial temperatures had a moderate and positive association (r=0.41; P<0.0001) during all experiment. This study highlights that the ocular surface temperature obtained through infrared thermography can be a superficial body temperature indicators, besides being a non-invasive and fast method of measurement. However, more research is needed to deepen the relationship between ocular surface temperature and cortisol during chronic stress.(AU)