Disseminating Equine Research and Teaching Videos Through the Institutional Repository: A Collaboration

Institutional repositories manage and disseminate a University's scholarly output and provide a multitude of benefits to the organization and society. Rutgers University Libraries is actively expanding its repository to include materials with scholarly merit that are currently siloed in academic departments or otherwise unpreserved and unavailable to the public. This article describes a collaboration between Rutgers Libraries faculty and Rutgers teaching faculty which is enabling discovery of a significant collection of video data relating to equine behavioral responses. The article describes the research, the repository tools, and the process of developing and customizing metadata to bring this collection to light.     

Physiological Changes in Mink (Mustela vison) Dams Subjected to Weaning at Different Times during Lactation

The influence of time of weaning on weight changes, and on hormone and electrolyte status in domestic mink (Mustela vison) dams raising at least five kits per litter was examined. The kits were weaned at either day 42 (group 1) or day 49 (group 2) after birth. The dams were weighed and urine and blood were sampled from day 29 to day 56 after delivery. A considerable loss of dams' body weight, constituting 6.3% in group 1 and 8.1% in group 2, was noticed on the day after weaning, indicating a greatly reduced food consumption on the day of weaning. No changes in plasma aldosterone and no significant decrease in urinary sodium concentration were seen in dams after removal from their litters, whereas, irrespective of time of weaning, urinary sodium and chloride concentrations were halved a few days after weaning compared with the other group. The plasma cortisol concentration was high before and during weaning and was nearly halved 1 week after weaning, implying less strain on the dams after weaning. It is concluded that the weaning period is a most vulnerable and stressful period to the dams irrespective of the actual time of weaning.     

The effect of the maturity and prior breeding activity of rams and body condition score of ewe hoggets on the reproductive performance of ewe hoggets

Abstract

AIM: To determine the effect of age and prior use of mature rams at a given ram-to-ewe ratio, and the effect of body condition on breeding performance and pregnancy rate of ewe hoggets.

METHODS: Ewe hoggets (n=733) aged 7–8 months were weighed and their body condition scored, then randomly assigned to one of three treatment groups (Day 0) and joined with either four two-tooth rams (20 months of age) not used previously (n=244; Two-tooth), four mixed-aged mature rams that had not been used earlier in the season (n=244; Mature-fresh), or four mixed-aged mature rams that had been used with mature ewes immediately prior to joining with hoggets (n=245; Mature-used). The breeding period was 34 days. Ewe hoggets were identified as having been marked during the first 17 days only, during both 17-day periods, during the second 17 days only, or not marked. Hoggets were re-weighed on Day 34, and pregnancy status determined using ultrasound on Day 92. The breeding soundness of the rams was assessed on Days ?34 and ?1.

RESULTS: Semen samples obtained from the rams did not differ significantly in any of the parameters measured (p>0.05). Ewe hoggets joined with Mature-fresh rams were less likely (p<0.05) to be marked in the second 17 days of breeding only than those joined with either Two-tooth or Mature-used rams. No other breeding parameters were affected by breeding group (p>0.05). Hoggets marked in the first 17 days only were heavier (p<0.05) at Day 0 than those marked in the second 17 days only or not marked. Hoggets diagnosed as twin-bearing were heavier (p<0.05) than non-pregnant or single-bearing hoggets. Those hoggets marked in the first 17 days only had a greater (p<0.05) body condition score (BCS) than those marked in the second 17 days only or not marked at all. These differences were no longer apparent after correction for liveweight (LW).Correction for LW at Day 0 or change in LW during the breeding period did not affect the results for breeding performance.

CONCLUSIONS: Under the conditions of this study, two-tooth rams and mature rams that had been used previously were just as suitable as mature rams that had not been used previously for breeding with ewe hoggets. Further studies are warranted to verify this result. The re-use of rams without reducing breeding performance would reduce breeding costs and may make breeding hoggets a more viable option for farmers. The BCS of ewe hoggets affected breeding performance, and can thus be used to identify those animals most suitable for breeding.     

Degradation of the neolignan, burchellin in the hemolymph of the bloodsucking insect Rhodnius prolixus

The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis.     

Mutational robustness of ribosomal protein genes

The distribution of fitness effects (DFE) of mutations is of fundamental importance for understanding evolutionary dynamics and complex diseases and for conserving threatened species. DFEs estimated from DNA sequences have rarely been subject to direct experimental tests. We used a bacterial system in which the fitness effects of a large number of defined single mutations in two ribosomal proteins were measured with high sensitivity. The obtained DFE appears to be unimodal, where most mutations (120 out of 126) are weakly deleterious and the remaining ones are potentially neutral. The DFEs for synonymous and nonsynonymous substitutions are similar, suggesting that in some genes, strong fitness constraints are present at the level of the messenger RNA.     

Effect of the thin cell layer technique in the induction of somatic embryos in Pinus patula Schl. et Cham

Pinus patula is a species commonly used for reforestation in Mexico.However,efficient methods for the mass production seedlings are required.Micropropagation particularly by somatic embryogenesis provides an option for the rapid multiplication of high-quality,genetically improved material.This study induces somatic embryogenesis in this species using the thin cell layer(TCL)technique.Two sources of explants(complete immature embryos;lTCL segments from immature embryos)were evaluated.The efficiency of TCL from longitudinal sections[lTCL]and transverse[tTCL]was evaluated.The results show using thin cell layers from immature embryos cultivated in 16 light/8 dark hours achieves induction of somatic embryos.A higher percentage of embryogenic callus was obtained when tTCL segments were used as an explant source.These results produced somatic embryos from tTCL segments of an immature embryo without germinating the seed,making the process more time efficient.In addition,this technique can be used to generate somatic embryogenesis in forest species that have low germination rates.     

Development of Procedures for Sex-sorting Frozen–Thawed Bovine Spermatozoa

Dairy bull sperm may be sex‐sorted, frozen and used to artificially inseminate heifers with acceptable fertility if the herd is well‐managed. One drawback to the technology is that donor bulls must be located within a short distance of the sorting facility in order to collect semen, which limits the number of bulls from which sorted sperm are available. A successful method used to overcome this limitation in sheep is sex‐sorting from frozen–thawed semen and refreezing for artificial insemination. This technique is attractive to the dairy industry, and therefore a series of three experiments was designed to investigate the optimal methods to prepare, sex‐sort and re‐freeze frozen–thawed bovine sperm. Sperm were prepared for sorting by density gradient separation in either PureSperm^® or BoviPure?, followed by staining in one of three diluents (Androhep^®, Bovine Sheath Fluid + 0.3% BSA or TALP buffer). Sperm were sorted and collected into Test yolk buffer, and frozen in an extender containing 0, 0.25, 0.375 or 0.5% Equex STM Paste. Frozen–thawed sperm were better orientated (p = 0.006) and had fewer damaged membranes (8.7 ± 0.6% vs 19.5 ± 2.4%; p = 0.003) after centrifugation in PureSperm^® rather than BoviPure? gradients. Sperm orientation (p < 0.05) and motility (69.9 ± 3.0 vs 55.6 ± 4.0; p < 0.001) were highest after staining in Androhep^® rather than in TALP buffer. Sperm were more motile (58.2 ± 4.7 vs 38.7 ± 3.5; p < 0.001) and had better acrosome integrity (74.3 ± 2.9 vs 66.8 ± 2.0; p < 0.001) after freezing in an extender containing 0.375% Equex STM Paste than in extender without Equex. Hence, a protocol has been developed to allow frozen–thawed bull sperm to be sex‐sorted with high resolution between the sexes, then re‐frozen and thawed with retention of motility and acrosome integrity.