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Sixteen (mean age = 1.1 ± 0.1 yr; mean BW = 478 ± 34 kg) Brahman-influenced bulls were used to determine the influence of fescue type on sperm characteristics and serum concentrations of prolactin, cortisol, and testosterone. Bulls were blocked by BW, scrotal circumference (SC), and pregrazing sperm characteristics and randomly assigned to graze toxic endophyte-infected (EI; 4 bulls/pasture; 2 pastures) or novel endophyte-infected (NE; 4 bulls/pasture; 2 pastures) tall fescue for 121 d. Semen was collected by electroejaculation, and SC was measured and blood samples collected monthly. Sperm were evaluated for motility and morphology with an integrated visual optical system. Overall mean concentration of prolactin was decreased more (P < 0.01) in EI bulls than NE bulls from May to August. Scrotal circumference was not affected by fescue type (P = 0.58); overall SC averaged 36.7 ± 2.3 cm. Percentage of live sperm was not different (P = 0.24) between NE bulls (80%) than EI bulls (67%) in July and August. Bulls grazing NE fescue had more (P < 0.06) motile sperm than EI bulls in July and August. Percentages of progressive (57 vs. 38%, NE and EI, respectively; P < 0.06) and rapid (67 vs. 46%, NE and EI, respectively; P = 0.04) sperm were greater from bulls grazing NE than EI bulls in July and August. Average velocity of the smoothed sperm path and progressive velocity in a straight line from the beginning to the end of the sperm track were slower (P < 0.09) in EI bulls than NE bulls and were slower (P = 0.04) in August compared with July. Mean width of head oscillation as the sperm swims was less (P < 0.06) in August than July. Concentrations of cortisol and testosterone were not (P > 0.10) influenced by fescue type. Semen from bulls grazing EI had reduced motility and morphology than bulls grazing NE. Detrimental effects of toxic fescue may not be mediated by cortisol, testosterone, or both. Semen quality of bulls grazing toxic EI tall fescue was decreased with increased maximum ambient temperatures.

Sixteen (mean age = 1.1 ± 0.1 yr; mean BW = 478 ± 34 kg) Brahrnan-influenced bulls were used to determine the influence of fescue type on sperm characteristics and serum concentrations of pro-lactin, cortisol, and testosterone. Bulls were blocked by BW, scrotal circumference (SC), and pregrazing sperm characteristics and randomly assigned to graze toxic endophyte-infected (El; 4 bulls/pasture; 2 pastures) or novel endophyte-infected (NE; 4 bulls/pasture; 2 pastures) tall fescue for 121 d. Semen was collected by electroejaculation, and SC was measured and blood samples collected monthly. Sperm were evaluated for motility and morphology with an integrated visual optical system. Overall mean concentration of prolactin was decreased more (P < 0.01) in El bulls than NE bulls from May to August. Scrotal circumference was not affected by fescue type (P 0.58); overall SC averaged 36.7 + 2.3 cm. Percentage of live sperm was not different (P = 0.24) between NE bulls (80%) than El bulls (67%) in July and August. Bulls grazing NE fescue had more (P < 0.06) motile sperm than El bulls in July and August. Percentages of progressive (57 vs. 38%, NE and El, respectively; P < 0.06) and rapid (67 vs. 46%, NE and El, respectively; P = 0.04) sperm were greater from bulls grazing NE than El bulls in July and August. Average velocity of the smoothed sperm path and progressive velocity in a straight line from the beginning to the end of the sperm track were slower (P < 0.09) in El bulls than NE bulls and were slower (P = 0.04) in August compared with July. Mean width of head oscillation as the sperm swims was less (P < 0.06) in August than July. Concentrations of cortisol and testosterone were not (P > 0.10) influenced by fescue type. Semen from bulls grazing El had reduced motility and morphology than bulls grazing NE. Detrimental effects of toxic fescue may not be mediated by cortisol, testosterone, or both. Semen quality of bulls grazing toxic El tall fescue was decreased with increased maximum ambient temperatures. [PUBLICATION ABSTRACT]

Abstract Crossbred beef steers (n = 106; BW = 96 ± 3.9 kg; Age = 74 ± 2.0 d) were blocked by parity of dam (≤ 2 or > 2 parities), stratified by BW, age, and sire, and assigned randomly to 1 of 3 implant treatments on d 0: 1) Ralgro; 36 mg zeranol, 2) Component E-C; 100 mg progesterone and 10 mg estradiol with 29 mg tylosin, 3) Control; received no growth promoting implant. Body weights were recorded on d -7, 0 (branding), 57, 98, and 156 (weaning). Sera was harvested from a subset of calves (n = 48) for the analysis of blood urea nitrogen (BUN) and NEFA on d 0, 57, 98, and 156. Data were analyzed using the MIXED procedures of SAS with calf serving as the experimental unit for all dependent variables and analysis of BUN and NEFA utilized a repeated measures statement with main effects of treatment, day, and the interaction of treatment × day with α = 0.05. Day 0 BW were not different (P = 0.90) between treatments. Interim BW on d 57 and 98 were not affected (P ≥ 0.53) by growth promoting implants. Weaning BW were similar (P = 0.19) between all treatments; however, there was a tendency (P = 0.08) for greater weaning weights in implanted calves (239 kg) compared to non-implanted calves (225 kg). Average daily gain from d 0 to 57 was not affected (P = 0.59) by the use of growth promoting implants. Implanted steers had greater (0.91 vs. 0.79 kg/d; P = 0.04) ADG from d 57 to 98; however, type of implant was not different (P = 0.84). Average daily gain from d 98 to 156 was greater (P = 0.05) in Ralgro (1.25 kg/d) and Component E-C (1.21 kg/d) compared to Control (1.12 kg/d). Overall ADG from d 0 to 156 (weaning) was greater (P = 0.03) in Ralgro (0.91 kg/d) and Component E-C (0.90 kg/d) compared to Control (0.82 kg/d). There was no interaction (P = 0.86) of treatment × day, nor a main effect (P = 0.54) of treatment for NEFA concentrations. A treatment × day interaction was not detected (P = 0.27) for BUN concentrations; however, BUN were greater (P = 0.01; treatment main effect) in Control compared to Component E-C whereas Ralgro was intermediate. Implantation of male calves at branding, regardless of implant type, increased growth performance prior to weaning.

Crossbred beef steers (n = 106; BW = 96 ± 3.9 kg; Age = 74 ± 2.0 d) were blocked by parity of dam (≤ 2 or > 2 parities), stratified by BW, age, and sire, and assigned randomly to 1 of 3 implant treatments on d 0: 1) Ralgro; 36 mg zeranol, 2) Component E-C; 100 mg progesterone and 10 mg estradiol with 29 mg tylosin, 3) Control; received no growth promoting implant. Body weights were recorded on d -7, 0 (branding), 57, 98, and 156 (weaning). Sera was harvested from a subset of calves (n = 48) for the analysis of blood urea nitrogen (BUN) and NEFA on d 0, 57, 98, and 156. Data were analyzed using the MIXED procedures of SAS with calf serving as the experimental unit for all dependent variables and analysis of BUN and NEFA utilized a repeated measures statement with main effects of treatment, day, and the interaction of treatment × day with α = 0.05. Day 0 BW were not different (P = 0.90) between treatments. Interim BW on d 57 and 98 were not affected (P ≥ 0.53) by growth promoting implants. Weaning BW were similar (P = 0.19) between all treatments; however, there was a tendency (P = 0.08) for greater weaning weights in implanted calves (239 kg) compared to non-implanted calves (225 kg). Average daily gain from d 0 to 57 was not affected (P = 0.59) by the use of growth promoting implants. Implanted steers had greater (0.91 vs. 0.79 kg/d; P = 0.04) ADG from d 57 to 98; however, type of implant was not different (P = 0.84). Average daily gain from d 98 to 156 was greater (P = 0.05) in Ralgro (1.25 kg/d) and Component E-C (1.21 kg/d) compared to Control (1.12 kg/d). Overall ADG from d 0 to 156 (weaning) was greater (P = 0.03) in Ralgro (0.91 kg/d) and Component E-C (0.90 kg/d) compared to Control (0.82 kg/d). There was no interaction (P = 0.86) of treatment × day, nor a main effect (P = 0.54) of treatment for NEFA concentrations. A treatment × day interaction was not detected (P = 0.27) for BUN concentrations; however, BUN were greater (P = 0.01; treatment main effect) in Control compared to Component E-C whereas Ralgro was intermediate. Implantation of male calves at branding, regardless of implant type, increased growth performance prior to weaning.

An abstract of a study by Acharya et al determining the effect of semen extender and storage temperature on motility of ram semen is presented. Results indicated that progressive motility of ram sperm is greatly reduced within 24 h storage, regardless of extender or storage temperature.

This study evaluated the effect of tracemineral supplementation on bull semen quality, as measured by computer-assisted sperm analysis. Angus and Gelbvieh × Angus bulls assigned to inorganic (n = 9) and organic (n = 10) trace-mineral treatments were maintained in drylot pens and fed mixed grass hay. Three times weekly bulls were individually fed rations containing either inorganic or a mixture of inorganic and organic Zn, Cu, Co, and Mn trace mineral for 123 d (mid-May to early September). Starting on d 60, semen was collected by electroejaculation weekly for a 9-wk period (mid-July until early September) and evaluated by computer-assisted sperm analysis for motility parameters within 5min of collection. Data were analyzed by treatment, week, and their interaction using SAS PROC Mixed for repeated measures. Bulls supplemented with organic trace minerals had a greater (P = 0.02) percentage of motile sperm than those supplemented with inorganic trace minerals (65.5 vs. 56.1%, respectively). Likewise, percentage of progressive sperm was greater (P = 0.01) for bulls receiving organic (47.0%) versus only inorganic (38.4%) trace mineral. Sperm with rapid motility (path velocity >50 μm/s) was also greater (P = 0.03) for bulls supplemented with organic compared with bulls receiving inorganic trace mineral (62.3 vs. 52.8%, respectively). Sperm motility is the single most important semen quality parameter influencing bull fertility. Results suggest organic trace-mineral supplementation may improve bull semen quality. Additional studies are needed to determine whether this improvement in semen quality translates into improved pregnancy rates.

An abstract of a study by Ball et al determining the effects of monensin, an ionophore that improves energy efficiency through alteration of VFA production in the rumen, in first or second parity lactating beef cows in a spring- and fall-calving herd is presented. The total percentage of cows bred regardless of conception method was similar between treatments (P = 0.80); however, there was a tendency for a greater percentage of pregnant cows in the spring-calving herd compared to the fall-calving herd (P = 0.06). Monensin supplementation did not affect gains of fall-calving cows consuming low quality forage but may affect spring-calving cows consuming a greater plane of nutrition.

This study investigated whether Estrotect estrous-detection patches could be used as a simple, cost-effective reproductive-management tool to identify cyclic animals before breeding, to distinguish between cows or heifers conceiving to AI versus natural service, and to determine seasonal pregnancy rate after bull removal. A secondary objective was to determine whether altering the timing of gonadorelin (GnRH) treatment in a 14-d progesterone-Select Synch synchronization protocol could reduce labor costs without reducing protocol effectiveness. Compared with cyclic status determined via ultrasonography, Chi-square analysis indicated that estrous-detection patches monitored for a 4-wk period were able to correctly identify 79% of cyclic and 86% of noncyclic heifers (P<0.01). Estrous-detection patches were 96 and 98% accurate in identifying heifers and cows pregnant by AI, respectively. When compared with pregnancy data obtained via ultrasonography, estrous-detection patches were 76% accurate in identifying pregnant heifers and 87% accurate in identifying pregnant cows at the end of the breeding season (P<0.01). Data indicated that accuracy of estrous-detection patches in predicting pregnancy depends upon cyclic status of the herd. Estrus was synchronized in lactating cows using a 14-d CIDR-Select Synch protocol where timing of GnRH administration occurred at time of CIDR removal (d 14) or 24h later (d 15). In both treatments, prostaglandin F2α was given 7 d after GnRH. Estrous response and AI pregnancy rates were similar (P>0.10), regardless of timing of GnRH treatment. Treatment with GnRH at CIDR removal reduced labor costs and animal handling.