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Epithelial ion transport disorders, including cystic fibrosis, adversely affect male reproductive function by nonobstructive mechanisms and by obstruction of the distal duct. Continuous cell lines that could be used to define ion transport mechanisms in this tissue are not readily available. In the present study, porcine vas deferens epithelial cells were isolated by standard techniques, and the cells spontaneously immortalized to form a porcine vas deferens epithelial cell line that we have titled PVD9902. Cells were maintained in continuous culture for >4 yr and 200 passages in a typical growth medium. Frozen stocks were generated, and thawed cells exhibited growth characteristics indistinguishable from their nonfrozen counterparts. Molecular and immunocytochemical studies confirmed the origin and epithelial nature of these cells. When seeded on permeable supports, PVD9902 cells grew as electrically tight (>6,000 [OMEGA]*[cm.sup.2]), confluent monolayers that responded to forskolin with an increase in short-circuit current (I.sub.sc; 8 [greater than or equal to] 1[mu]A/[cm.sup.2]) that required [Cl.sup.-], HC[O.sup.-.sub.3] a[Na.sup.+] ,and was partially sensitive to bumetanide, mRNA was expressed for a number of anion transporters, including CFTR, electrogenic [Na.sup.+]-HC [O.sup.-.sub.3] co-transporter 1b (NBCe1b), downregulated in adenoma, pendrin, and [Cl.sup.-]/formate exchanger. Both forskolin and isoproterenol caused an increase in cellular cAMP levels. In addition, PVD9902 cell monolayers responded to physiological (i.e., adenosine, norepinephrine) and pharmacological [i.e., 5'-(N-ethylcarboxamido) adenosine, isoproterenol] agonists with increases in [I.sub.sc]. Unlike their freshly isolated counterparts, however, PVD9902 cells did not respond to glucocorticoid exposure with an increase in amiloride-sensitive [I.sub.sc]. RT-PCR analysis revealed the presence of both glucocorticoid and mineralocorticoid receptor mRNA as well as mRNA for the [alpha]-and [gamma]-subunits of the epithelia [Na.sup.+] channels ([alpha]-and [gamma],-ENaC), but not [beta]-ENaC. Nonetheless, PVD9902 cells recapitulated most observations in freshly isolated cells and thus represent a powerful new tool to characterize mechanisms that contribute to male reproductive function. male reproductive tract; cystic fibrosis; epithelial [Na.sup.+] channel expression; glucocorticoid receptor; adrenergic; vasopressin

Our objective was to determine whether onset of first postpartum ovulation would be altered in suckled cows nursing an unrelated calf in the presence or absence of their own nonsuckling calf. In a 2-yr study, Angus x Hereford cows were assigned randomly to five treatments between d 13 and 18 postpartum for 4 wk: 1) own calf was weaned (OCW, n = 9); 2) own calf was present continuously (OCP, n = 12); 3) own calf was present continuously but restricted from udder contact (OCR, n = 9); 4) unrelated calf was present continuously after own calf was removed (UCP, n = 10); and 5) unrelated calf was present continuously and own calf was present but restricted as in the OCR treatment (OCR+UCP, n = 10). Interval to the first increase in progesterone (ovulation) was less (P < .05) in OCW (14.7 [+ or -] 3.4 d) and OCR (19.9 [+ or -] 3.4 d) than in the OCP (35.0 [+ or -] 2.9 d), UCP (38.0 [+ or -] 3.4 d), and OCR+UCP (37.6 [+ or -] 3.4 d) treatments. The OCW cows showed no maternal bond with their own calves after 4 wk of treatment, whereas OCR, OCP, and OCR+UCP cows were bonded to their own natural calves. Cows in the UCP treatment, suckled by unrelated calves, formed new maternal bonds with those calves, resulting in prolonged anovulation. Further, OCR+UCP cows had prolonged anovulation because maternal bonds were maintained with their own restricted calves while milk was removed by unrelated calves. We conclude that milk removal preceded by a continuously reinforced cow-calf bond (original or reestablished) is essential to prolong anovulation in beef cows. Key Words: Suckling, Anestrus, Progesterone, Cows

As undergraduate animal science student populations shift to more diverse backgrounds, hands-on learning activities have been shown to increase engagement and are necessary for students with diverse backgrounds in animal exposure. Student feedback and engagement in the classroom suggest that students value and seek hands-on learning opportunities. The outcomes of lecture courses with concurrent enrollment in laboratory or hands-on style courses warrant evaluation. Thus, our study aimed to investigate potential impacts of concurrent enrollment in lecture and laboratory sections on final course percentages. Data were collected from students enrolled in the farm animal reproduction lecture and (or) laboratory courses in the spring semesters of 2021 and 2022 including final course percentage in lecture, college classification (sophomore, junior, senior), gender, and degree option (science or production focus). Student learning outcomes and structure of the laboratory course were designed to provide hands-on learning opportunities that coincided with concepts discussed in lecture. A total of 193 students majoring in Animal Science were included in the analysis, of which 65 were concurrently enrolled in the laboratory and lecture, and 128 were enrolled in the lecture alone. Students concurrently enrolled in laboratory and lecture had a greater (P < 0.03) final course percentage in the lecture as compared with those enrolled in lecture alone. Students in the science degree option had a greater (P < 0.01) final lecture course percentage when compared with those in the production degree option. Neither student gender nor college classification affected (P > 0.10) final lecture course percentage. At the end of the semester, students were surveyed about perceived value of the laboratory course on their learning. Among students enrolled in laboratory sections, only 1.6% indicated the hands-on activities did not improve their learning of course concepts in lecture. In 2022, 82.2% of students enrolled in lecture, but not in a laboratory section indicated they wished they had enrolled in a laboratory section, because they believe it would have improved their grade in the lecture course. These student beliefs are supported by our results which indicate that not only did taking the laboratory and lecture together improve student final course percentages, but that students valued the hands-on learning opportunities provided in laboratory sections. Benefits of hands-on learning activities warrant providing student access to these types of activities and incorporating them in lecture courses when laboratory classes are unavailable to improve student performance and experiences. [ABSTRACT FROM AUTHOR]

Fertility is a critically important factor in cattle production because it directly relates to the ability to produce the offspring necessary to offset costs in production systems. Female fertility has received much attention and has been enhanced through assisted reproductive technologies, as well as genetic selection; however, improving bull fertility has been largely ignored. Improvements in bull reproductive performance are necessary to optimize the efficiency of cattle production. Selection and management to improve bull fertility not only have the potential to increase conception rates but also have the capacity to improve other economically relevant production traits. Bull fertility has reportedly been genetically correlated with traits such as average daily gain, heifer pregnancy, and calving interval. Published studies show that bull fertility traits are low to moderately heritable, indicating that improvements in bull fertility can be realized through selection. Although female fertility has continued to progress according to increasing conception rates, the reported correlation between male and female fertility is low, indicating that male fertility cannot be improved by selection for female fertility. Correlations between several bull fertility traits, such as concentration, number of spermatozoa, motility, and number of spermatozoa abnormalities, vary among studies. Using male fertility traits in selection indices would provide producers with more advanced selection tools. The objective of this review was to discuss current beef bull fertility measurements and to discuss the future of genetic evaluation of beef bull fertility and potential genetic improvement strategies. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) have effects on characteristics of spermatozoa, including mitochondrial membrane potential, acrosomal integrity, and structural abnormalities that can influence spermatozoa function. The objective was to determine correlations between sperm response to ROS and functional sperm measurements using ejaculates collected as part of bull breeding soundness exams (BSE). Semen samples were collected from Angus and Charolais bulls (403 ± 11 d of age; n=46) over three days during yearling BSEs. A veterinarian evaluated spermatozoa for percent motility and normal morphology, and percentage progressive motility was measured using an iSperm® analyzer. If ejaculates met minimum thresholds for passing a BSE, they were diluted to 70 million cells/mL using BoviFree® and sent overnight for flow cytometry evaluation. Flow cytometry assays including acrosome and cell membrane integrity, mitochondrial energy potential, and oxidation status. Data were analyzed using Pearson's correlation coefficients in SAS. Percentage live spermatozoa with positive ROS status was correlated (r = 0.53; P < 0.001) with percentage progressive motility. Percentage live spermatozoa with negative ROS status was moderately correlated with percentage spermatozoa exhibiting secondary abnormalities (r = 0.33; P = 0.02) and tended to be lowly correlated (r = 0.28; P = 0.06) with percentage spermatozoa exhibiting primary abnormalities. Percentage live spermatozoa that had disrupted acrosomes was strongly correlated (r = 0.66; P < 0.001) with percentage live spermatozoa with negative ROS and also moderately negatively correlated (r = -0.31; P = 0.04) with percentage live spermatozoa with positive ROS. Percentage live spermatozoa with positive ROS status was correlated (r = 0.58; P < 0.001) with percentage of spermatozoa with active mitochondrial membranes. Live spermatozoa with positive ROS were strongly correlated (P< 0.001) with live spermatozoa (r=0.94) and live spermatozoa with intact acrosome (r=0.92). These data confirm previous research that shows the detrimental effects of ROS on spermatozoa function. [ABSTRACT FROM AUTHOR]

Flow cytometry has been used as a reliable and objective tool for bull sperm quality assessments and identification of sub-fertility. Our objective was to determine if breed differences exist in sperm quality assessments using flow cytometry when evaluating semen from yearling Angus and Charolais bulls that passed breeding soundness exam (BSE) semen evaluation thresholds. Ejaculates were collected via electroejaculation on one of three consecutive days from yearling (403.15 ± 11.19 d age) Charolais (n=23) and Angus (n=23) bulls as part of a BSE. BSEs were conducted by one veterinarian and all bulls met all requirements as set by the Society for Theriogenology. An additional sperm motility analysis was conducted with the iSperm analyzer. Ejaculates were diluted in BoviFree to 70 million cells/mL and sent overnight for flow cytometry analyses. Sperm flow cytometry analyses included: acrosome and cell membrane integrity, mitochondrial energy potential, and oxidation status. The GLIMMIX procedure of SAS with bull as experimental unit, bull breed as the main effect and collection date as a random variable was used to assess potential differences in sperm quality variables. Neither iSperm (P = 0.26) nor visual assessment (P = 0.66) of sperm motility differed among breeds. Bull breed did not influence (P = 0.83) total percentage of viable cells, nor percentage of viable cells with intact acrosomes (P = 0.83). When evaluating oxidation status by measuring reactive oxygen species, bull breed did not influence (P = 0.92) percentage of live sperm cells with positive reactive oxygen species status. There was a tendency (P = 0.10) for a greater percentage of sperm from Charolais bulls (31.1% ± 3.35) to have positive mitochondrial energy potential as compared with Angus bulls (17.6% ± 3.35). Bull breed appears to have little influence on sperm quality assessments among yearling bulls meeting threshold requirements for passing BSEs. [ABSTRACT FROM AUTHOR]