Silvopastoral systems as a tool for recovering degraded pastures and improving animal thermal comfort indexes in Northern Ecuador.

Athropogenic changes have caused profound repercussions, which have led to a progressive degradation of natural resources. In the case of the Ecuadorian Amazon, the high rate of deforestation, changes in land use and extensive livestock management have led to low production rates with an eminent threat to the thermal comfort of ruminants. The present study aimed to contrasts how the use of SPs represents a viable option for the reconversion of extensive livestock farming. The current study compared the use of silvopastoral systems (SPs) versus a conventional pastoral system, as an alternative for the recovery of degraded areas. Therefore, under a completely randomized block design, Brachiaria decumbens was evaluated with three of treatments, such as Control = conventional pastoral, SPs1 = density 100 trees/ha-1 and SPs2 = 150 trees/ha-1. All environmental variables and bioclimatic indicators (temperature and radiant heat load: RHL) were shown to be mitigated under SPs (P < 0.001), which translates into better thermal comfort for ruminants (RHL; 638 vs. 1749 ± 40; P < 0.001). Although, the treatments affected all the agronomic variables of Brachiaria decumbens (P < 0.001 to 0.004), the month conditioned most of the chemical determinations (P < 0.001). This means that the use of SPs in the medium or long term could contribute to the recovery of pastures in degradation processes. Consequently, SPs as a clean production alternative would help improve aspects such as soil quality, agronomic yields, as well as greater nutritional quality of pastures. In any case, long-term studies should be performed to contrast our responses.

Repeated temporary threshold shift and changes in cochlear and neural function.

A robust temporary threshold shift (TTS) can create significant primary damage to the auditory synapse, termed cochlear synaptopathy (CS). The common model applied to examination of this pathology is a single noise exposure or extended duration exposures at relatively high noise dosages. It is unclear if a single noise exposure that does not produce physiological changes consistent with CS (such as suppressed suprathreshold responses) can create evidence consistent with the pathology induced by repeated exposures. Here, we exposed 16-week (wk) old Sprague-Dawley rats to repeated noise exposures (4 consecutive days, 8-16 kHz octave-band of noise, 97 dB SPL for 2 h) and examined measures of cochlear function (distortion product otoacoustic emissions) and auditory neural integrity (auditory brainstem response, wave 1 amplitude). Our results demonstrated a mean maximal threshold shift of 16 dB at 24 h post the initial noise exposure. Subsequent daily repeated exposures (4 consecutive days) resulted in diminished threshold shift at 24 h post repeated TTS. In addition to recovered thresholds, no sustained reduction in suprathreshold responses was observed. The findings are consistent with conditioning literature suggesting diminished TTS with repeated exposures. Repeated TTS that was not individually synaptopathic did not produce physiological evidence consistent with acute CS.

Comparison of electroejaculation and transrectal massage for semen collection in range and yearling feedlot beef bulls.

Two experiments were conducted to compare electroejaculation (EE) and transrectal massage (RM) of the ampullary region for semen collection from beef bulls, and to determine the effect of semen collection method on semen traits. In experiment 1, semen was collected either by EE or RM randomly assigned on an alternate basis in 137 range beef bulls unaccustomed to being handled. The maximum time allowed for RM was 4 min and if no semen was obtained, EE was used. In experiment 2, semen was collected from 39 yearling feedlot beef bulls that were accustomed to being handled, by RM followed immediately by EE. The maximum time allowed for semen collection by both methods was 4 min. In both experiments, sperm concentration, percent of progressively motile sperm, percent of sperm staining alive, and sperm morphology were determined. In experiment 1, RM resulted in fewer (P<0.001) successful semen collections and fewer bulls with penile protrusion than EE (80.9% versus 100% and 54.4% versus 91.5%, respectively). The success of RM was not influenced by bull age or breed, or by the veterinarian performing the massage. Transrectal massage required more time (30s, P<0.001) for obtaining a semen sample and resulted in samples with lower sperm concentration (P<0.001), percent motile sperm (P<0.05) and percent live sperm (P<0.001) when compared to EE. In experiment 2, EE and RM were equally effective for obtaining a semen sample (97.4 and 94.9%, respectively), but the proportion of bulls exhibiting penile protrusion during semen collection was lower (P<0.0001) with RM compared to EE. Percent of sperm staining alive was also lower (P<0.01) in samples collected by RM. Sperm morphology (normal sperm, head defects, midpiece defects, proximal cytoplasmic droplets, and detached sperm heads) did not differ between samples collected by EE and RM. In conclusion, semen could be collected by transrectal massage from approximately 80% of range beef bulls and from 95% of yearling beef bulls accustomed to handling. Sperm morphology was not affected by the method of semen collection, but percent of motile sperm and live sperm were lower in samples collected by RM. A reduced ability to stimulate penile protrusion with RM precluded examination of the penis in a large proportion of bulls.