Animal - Open Space最新文献

This study investigated the impact of the age at which heifers conceive for the first time on the growth and reproductive development of their female offspring. A total of seven heifers pregnant at 15 months of age (15M), nine heifers pregnant at 27 months of age (27M) and seven multiparous pregnant cows (Adult) were used in the present trial. All dams were pregnant by AI from a single sire and managed in a single group during gestation, lactation and rearing stages. After weaning heifer calves were stocked on natural pastures. Progeny of heifers that gestated for the first time at different ages did not present differences in growth; however, progeny of 15 and 27M dams had reduced BW, longissimus muscle area and 12th fat thickness compared to progeny of adult dams (P < 0.05). Diameter of the largest follicle was greater in progeny born to Adult compared to progeny born to 15 and 27M (P = 0.04). Reproductive tract score (RTS) in heifers born to Adult at 399 days of age was greater compared to heifers born to 27M, and this category presented greater development than heifers born to 15M (P = 0.02). At 435 days of age, the heifers born to Adult had a greater percentage defined as pubertal compared to the progeny of 15 and 27M (P = 0.04). At 495 days of age, the weight of uterus, ovaries and corpora lutea were not affected by the age of dams at calving (P > 0.25). These data indicated that the age at which heifers received their first service affects female offspring growth RTS at early ages, but it does not have any impact in organ development after diet with a high energy level.

This study compared two collection methods (CMs) to obtain ileal content from broiler chickens to determine apparent ileal amino acid digestibility coefficients (AIAAD). CM1 consisted of collecting the digesta by gently squeezing the ileum, while in CM2, the ileal digesta was flushed with distilled water. A total of 130 one-day-old male chicks were randomly distributed among 10 cages, using five replicate cages per CM. Birds were fed ad libitum with a standard starter diet from 0 to 18 d of age. At 18d, the diet switched to a corn-based semi-purified diet with 0.5% titanium dioxide (TiO2) as the indigestible marker. At 21d, birds were euthanized, and ileal digesta was collected using one of the two CMs. Bird performance was monitored; feed and lyophilized ileum content samples were analyzed to determine amino acids (AAs) and Ti content to determine AIAAD. A two-sided T-test and an F-test two-sided were performed to determine differences among the CMs’ means and variances, respectively. All significant differences were considered at a P-value < 0.05. Bird performance was similar for both groups throughout the experiment (P > 0.05). No significant differences between CMs were observed in the AIAAD coefficients for any of the amino acids analyzed (P < 0.05). The variances were significantly different for 6 AA (Iso, Lys, Thr, Ala, Asp, Glu; P < 0.05). In addition, four AAs approach significance (Leu, Met, Val, Pro; P < 0.1). The numeric values of the AAs variances were consistently higher when the sample was obtained using CM1. Squeezing may increase variability by enhancing endogenous losses like sloughed cells and mucin, underestimating digestibility in some samples. Using CM2 (flushing with distilled water) would provide more consistent and uniform results. This approach not only diminishes the likelihood of errors but also contributes to the standardization of methodologies applied in digestibility trials within the poultry research field.

Heat stress is a major factor affecting animal productivity in tropical countries, with effects on physiological, hormonal, and behavioral responses. This study aimed to assess the differences in these responses between heat-tolerant and less heat-tolerant hair sheep during heat stress. Twenty-four Santa Ines sheep were selected from a group of 80 sheep, with 12 identified as heat-tolerant and 12 as less heat-tolerant based on thermotolerance assessment. The animals were exposed to heat stress in a climatic chamber at an average temperature of 36 °C (1000–1600 h) for 8 days and maintained at 28 °C (1600–1000 h). The rectal temperature, respiration rate, sweat rate, ocular surface temperature, body surface temperature, tympanic temperature, triiodothyronine level, and insulin level were measured. Skin samples were collected on the last day of the cycle for histological analysis. The results showed that the less heat-tolerant sheep had higher rectal and body surface temperatures (P < 0.05). Although no differences in skin morphology were observed between the groups, less heat-tolerant sheep continued to sweat for a longer period after the end of the thermal challenge to lose heat (P < 0.05). Less heat-tolerant animals also presented higher rectal temperatures during cooler hours and required more time to dissipate the excess heat. These findings suggest that there are individual differences in the thermoregulatory responses within the same breed under the same environmental conditions, and that breeding programs could be employed to produce more heat-tolerant, but still productive animals in tropical conditions.

Due to the evolution of welfare laws and the search for novel methods to study pig microbiota, the development of precise and non-invasive sampling methods is key to studying the microbial communities that inhabit the guts of pigs. Administering swallowable devices to pigs is always a challenge due to factors such as anatomy, the requirement for specific materials, and the need to restrain the animals. In this study, we describe a step-by-step protocol on how to administer Capsule for Sampling (CapSa), a biocompatible non-invasive device to study pig’s microbiota without harming the animals. The validation of the protocol was done through two different studies. In Study 1, 92 Swiss Large White pigs (BW: 6.45–71.3 kg) were administered two capsules each and monitored for the following 3 days for capsule retrieval. On day 3, all pigs were euthanised to locate the missing capsules directly from their gastrointestinal tracts. In Study 2, 16 Swiss Large White pigs were selected at weaning and administered CapSas at five different timepoints (T1: 52 ± 3; T2: 70 ± 3; T3: 83 ± 3; T4: 110 ± 3; T5: 126 ± 3 days of age). To retrieve the capsules in the faeces, pigs were monitored 3 days postadministration. At T5, the pigs were slaughtered, and CapSas that were not found in the faeces, termed as missing CapSas, were retrieved from their gastrointestinal tracts. The protocol entails acclimation of the animals, housing modifications, administration of a prokinetic agent (prucalopride) to facilitate gastric emptying, and oesophageal intubations to overcome challenges related to administration, gastric blockage, and retrieval of the capsules. In Study 1, 46.74% of the administered CapSas were found in the faeces within 72 h postadministration, with 47.67% retrieved within the first 24 h, and 28.26% were located in the stomach. The CapSa retrieval was lowest in light pigs (<12 kg). In Study 2, 75.6% of CapSas were recovered in the faeces within 72 h postadministration, with 51.23% retrieved within the first 24 h. The CapSa retrieval rates varied depending on the administration time point being lowest at T1 and T3 and highest at T2 with intermediate values at T4 and T5. In both studies, the pH levels were affected by transit time (P < 0.01), resulting in a more acidic content when capsules were expelled after 36–40 h. To the contrary, the volume of the CapSa content was never affected by transit time (P < 0.05). In both studies, postmortem observations showed no health-related issues except one pig from Study 2 excluded due to respiratory distress. The present study describes a valid procedure for administering CapSa or any other swallowable devices in pigs. Moreover, this procedure is applicable to singular and repetitive administrations over the lifespan of pigs.

The infection of the endophytic fungus (Epichloë festucae var. lolii) within perennial ryegrass (Lolium perenne) pastures can produce toxic alkaloids, including lolitrem B and ergovaline which can negatively impact animal welfare and behaviour through causing ryegrass staggers as well as poor growth and increased sensitivity to heat stress. Wearable 3-axis acceleration sensors can provide an alternative to automatically monitor individual grazing livestock who need essential treatment to minimise the impact of grazing pastures infected with an endophyte. The objective of this study was to categorise changes in ruminating, eating and other behavioural activities of grazing lambs exposed to endophyte-infected perennial ryegrass via commercial accelerometer sensors. Lambs were fitted with the ear-mounted accelerometer sensors (CowManager SensOors, Agis, Harmelen, the Netherlands) and allocated randomly within live-weight strata to graze either endophyte-free (Control) or wild−type endophyte-infected (Endophyte) perennial ryegrass pasture. Live weight change, behaviour and incidence of staggers were monitored over a 2-month grazing period. Moderately severe staggers (score 4/5) occurred in 40% of lambs in the Endophyte treatment with a mean staggers score of 2.33 ± 0.41 across the group. Compared with control lambs, endophyte-infected lambs compensated for reduced eating (−36.0 min/day) and inactive (−43.7 min/day) duration in favour of increased ruminating (+40.2 min/day) and active (+29.9 min/day) duration. The sensors also identified diurnal adaptations in behaviour of lambs which were affected by endophyte staggers, presenting significant effects of endophyte challenge by hour interaction on the diurnal eating duration (P < 0.001), diurnal ruminating duration (P < 0.001), diurnal inactive duration (P < 0.001), diurnal active duration (P < 0.001) and diurnal highly active duration (P < 0.001). In conclusion, these sensors were able to detect subtle changes in the behaviour of grazing sheep that can be used to detect subclinical symptoms of ryegrass staggers when consuming ryegrass staggers.

This meta-analysis comprehensively evaluates the impact of production diseases on dairy cattle, examining a variety of physiological, metabolic, and behavioral traits. From an initial set of 3 349 records, a rigorous selection process resulted in 56 relevant articles, highlighting the strict criteria employed. The low inclusion rate of 1.67% underscores the dedication to studying quality and significance. Common reasons for exclusion, such as statistical methodology and the lack of a negative control group, emphasize the necessity for robust scientific investigation. The study reveals key indicators of production diseases, such as decreased milk production, weight loss, a low body condition score, digestive disorders, lameness, and respiratory distress. These findings align with existing knowledge, emphasizing the multifaceted nature of production diseases and their broad impact on dairy cattle health. Diseased animals consistently exhibit higher parameter values, supported by confidence intervals that indicate result precision. Subgroup analyses offer nuanced insights into the specific effects of diseases and interventions on different characteristics. Metritis and Mastitis significantly affect milk production, highlighting the economic implications for dairy farmers. Interventions such as improved milking techniques show promise. Similarly, interventions involving veterinary medications and controlled energy diets effectively mitigate weight loss, a low body condition score, and digestive disorders. The analysis underscores the vulnerability of dairy cattle to reproductive issues, metabolic imbalances, and increased susceptibility to infections. Interventions addressing these challenges include hormone therapy, balanced diets, and vaccination programs. Behavioral changes and feeding habits emerge as significant indicators of dairy cattle well-being. Ovarian cysts are identified as a major contributor to behavioral changes, necessitating targeted interventions. In conclusion, this meta-analysis provides valuable contributions to the field of dairy cattle health, offering specific insights into the effects of diseases and the effectiveness of interventions. These findings inform evidence-based practices for dairy stakeholders, ultimately enhancing animal welfare and promoting sustainable dairy production. However, establishing precise reference values presents challenges, warranting further investigation.