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European heritage breeds, such as the Blonde (B), Red (R), and Swallow-bellied (SB) Mangalica pig, display an extreme propensity to fatten and are reputed to produce superior quality pork. This suggests that Mangalica pork should command a higher price, and the Mangalica is a candidate breed to target niche markets within the United States. Our objectives were to test this hypothesis by (1) directly comparing growth performance and carcass merit of purebred Yorkshire (Y), B, R, and SB Mangalica pigs to identify the best breed for adoption, and (2) comparing indices of pork quality in purebred R, Y, and crossbred (R × Y) pigs to determine if crossbreeding represented a viable alternative to the adoption of purebred Mangalica. Daily feed intake, average daily gain (ADG), and feed efficiency were highest in Y and lowest in SB pigs with B and R ranked intermediately (p < 0.001). Backfat thickness was greatest in B and lowest in Y with R and SB ranked intermediately (p < 0.001). Marbling score was greatest in R pigs and lowest in Y pigs with B and SB ranked intermediately (p < 0.01). In contrast, loin eye area (LEA) was greatest in Y pigs compared to B, R, and SB (p < 0.001). Indices of meat quality were then compared in R, R × Y, and Y pigs. Backfat thickness and marbling scores were greater in R than R × Y and Y pigs (p < 0.001) while LEA was greater in Y than R × Y and R pigs (p < 0.001). Loin and ham ultimate pH, color, and firmness scores were significantly greater in R than R × Y or Y pigs (p < 0.05). Meanwhile, cook loss was significantly less in R than Y pigs (p < 0.007) while Warner-Bratzler Shear Force (WBS) was not different in chops between groups (p < 0.11). These data indicate that though Mangalica exhibit poorer growth performance, Mangalica pork exhibits superior pork quality attributes, suggesting that higher price points for Mangalica pork in niche markets are justified. [ABSTRACT FROM AUTHOR]

Trace minerals are known to play important roles in early embryo development. The study objective was to determine effects of trace mineral source on heifer reproductive performance. Beef heifers (n = 129) were randomly assigned to one of two treatments. From weaning through breeding, all heifers were individually fed a basal diet supplemented with cobalt (Co), copper (Cu), manganese (Mn), and zinc (Zn) either from organic sources (COMP; Cu, Mn, and Zn amino acid complexes and Co glucoheptonate; Availa-4, Zinpro Corporation, Eden Prairie, MN) or inorganic sources (INORG; Cu, Mn, and Zn hydroxychlorides; Intellibond C, M, and Z, Micronutrients, Indianapolis, IN) and Co as CoSO4. Blood samples and a reproductive tract score (RTS) were collected to determine pubertal status. All animals were synchronized and artificially inseminated. Pregnancy status was determined by lymphocyte gene expression, circulating concentrations of pregnancy-associated glycoproteins (PAGs), and by transrectal ultrasonography after artificial insemination. Embryonic loss was defined as when a previously pregnant animal was subsequently diagnosed not pregnant. Data were analyzed using the MIXED procedure in SAS. Puberty (P = 0.44), pelvic area (P = 0.74), RTS (P = 0.49), and estrus expression (P = 0.82) were not influenced by treatment. There was no effect of treatment (P = 0.37) or treatment by time (P = 0.19) on pregnancy, but there was a tendency (P = 0.13) for decreased embryonic loss among COMP heifers (27 ± 6%) compared to INORG heifers (38 ± 6%). There was a treatment by pregnancy status by time interaction (P < 0.01) on circulating PAG concentrations with PAG concentrations tending (P = 0.08) to be greater on day 25 among heifers in the COMP treatment compared to heifers in the INORG group. In summary, source of trace mineral did not affect puberty, RTS, pelvic area, or overall pregnancy success, but feeding complexed trace minerals tended to increase circulating PAG concentrations and embryo survival. [ABSTRACT FROM AUTHOR]

The ability to induce ovulation with an injection of GnRH facilitated the development of fixed-time artificial insemination (AI) protocols. However, animals that exhibit estrus prior to fixed-time AI have greater pregnancy success. Thus, the objectives of the present experiments were to determine the impact of estrus expression prior to fixed-time AI on timing of conception and to characterize the role of preovulatory estradiol in regulating changes in expression of uterine genes. In experiment 1, data were collected from 4,499 beef cows inseminated by fixed-time AI in 31 different herds. Animals that did not conceive to AI but exhibited estrus before timed-AI were more likely to conceive during cycle 1 after AI, and overall conceived earlier in the breeding season compared to animals that did not exhibit estrus. In experiment 2, beef cows were synchronized using a fixed-time AI protocol. Uterine horn biopsies and blood samples were collected on Day 0, 5, 10, or 16. Concentrations of estradiol on Day 0 did not influence expression of progesterone receptor, ER beta, or oxytocin receptor. Increased concentrations of estradiol on Day 0 increased expression of ER alpha from Days 0 to 5 of the estrous cycle. Furthermore, cows with increased concentrations of estradiol on Day 0 had increased expression of inhibin beta A, and uterine milk protein precursor. Thus, animals that do not exhibit estrus prior to fixed-time AI had decreased breeding season pregnancy success and conceived later in the breeding season, and preovulatory concentrations of estradiol likely play a major role in this establishment of pregnancy, not only directly by regulating uterine gene expression, but also indirectly throughout the subsequent estrous cycle. [ABSTRACT FROM AUTHOR]

The seasonal occurrence of organic contaminants, many of which are potential endocrine disruptors, entering the Potomac River, USA, watershed was investigated using a two-pronged approach during the fall of 2005 and spring of 2006. Passive samplers (semipermeable membrane device and polar organic chemical integrative sampler [POCIS]) were deployed in tandem at sites above and below wastewater treatment plant discharges within the watershed. Analysis of the samplers resulted in detection of 84 of 138 targeted chemicals. The agricultural pesticides atrazine and metolachlor had the greatest seasonal changes in water concentrations, with a 3.1- to 91-fold increase in the spring compared with the level in the previous fall. Coinciding with the elevated concentrations of atrazine in the spring were increasing concentrations of the atrazine degradation products desethylatrazine and desisopropylatrazine in the fall following spring and summer application of the parent compound. Other targeted chemicals (organochlorine pesticides, polycyclic aromatic hydrocarbons, and organic wastewater chemicals) did not indicate seasonal changes in occurrence or concentration; however, the overall concentrations and number of chemicals present were greater at the sites downstream of wastewater treatment plant discharges. Several fragrances and flame retardants were identified in these downstream sites, which are characteristic of wastewater effluent and human activities. The bioluminescent yeast estrogen screen in vitro assay of the POCIS extracts indicated the presence of chemicals that were capable of producing an estrogenic response at all sampling sites. [ABSTRACT FROM AUTHOR]

The article presents a study on organic contaminants in the surface waters of three geographically distinct agricultural waterheds. Passive sampling methodologies were used to conduct a chemical and toxicologic assessment of organic contaminants. The polar organic chemical integrative sampler and the semipermeable membrane device passive samplers targeted agrochemicals and persistent organic pollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides.

Transcript abundance of two forms of GnRH and its receptor have been characterized in bovine ovaries. The objective was to investigate the relationship of GnRH-1, GnRH-2, GnRH-R, intrafollicular estradiol (E2) and progesterone (P4) during follicular development. Ovaries were collected from beef cows at specific stages of follicular development [pre-selection (PRE, n = 9), postselection (POST, n = 9), and post-selection 24h after luteal regression (PG, n = 9)]. The largest follicle per stage was aspirated to obtain granulosa cells (GC) and follicular fluid (FF). Total cellular RNA was extracted from GC and RT-PCR was performed for GnRH-1, GnRH-2, GnRH-R and GAPDH. Radioimmunoassays were performed to determine FF concentrations of E2 and P4. Data were analyzed using the MIXED and REG procedures in SAS. There was no difference (P ≥ 0.23) in mRNA abundance of GnRH-2, GnRH-R or FF concentrations of P4 across follicular stages. There was an effect of stage on FF E2 (PRE: 17,925±20,273, POST: 28,458±21,503, and PG: 252,616±21,503 pg/mL; P < 0.01). Stage affected GnRH-1 mRNA abundance (PRE: 2.28±0.55, POST: 0.92±0.55, and PG: 0.11±0.55; P = 0.03). There was no relationship of GnRH-1 and GnRH-2 mRNA abundance or effect of FF P4 on GnRH-R mRNA abundance (P ≥ 0.23). There was no effect of FF P4 on GnRH-1 mRNA abundance (P = 0.68). There was no effect of FF E2 on GnRH-2 mRNA abundance (P = 0.66). As FF E2 increased GnRH-R mRNA abundance tended to increase (P = 0.10;r2=0.13). As FF P4 concentrations increased GnRH-2 mRNA abundance tended to decrease (P = 0.09;r2=0.12). As FF E2 increased GnRH-1 mRNA abundance decreased (P = 0.02;r2=0.20). In conclusion, there were differences in peptide and receptor mRNA abundance of GnRH in relation to FF E2 and P4 at specific stages of follicular development. This is supportive of a regulatory relationship between ovarian GnRH and steroidogenesis. This work is supported by AFRI Grant No.2018-67016-27578 from USDA. USDA is an equal opportunity provider and employer. [ABSTRACT FROM AUTHOR]

Bovine Viral Diarrhea Virus (BVDV) causes reproductive and economic losses in cattle. The objective of this study was to evaluate the influence of BVDV exposure on reproductive success (AI and breeding season conceptions). Well vaccinated cows (n = 367) and heifers (n = 540) from 9 different herds were synchronized using the 7-d CO Synch + CIDR protocol and were fixed-time AI (FTAI). On d 28 following insemination, blood samples were collected, and pregnancy status was determined by transrectal ultrasonography and the IDEXX Rapid Visual Pregnancy Test. Non-pregnant animals were resynchronized and FTAI a second time. In six herds bulls were comingled with females beginning 10-15 d after the second AI. Final pregnancy status was determined 33–80 d following the first pregnancy diagnosis. Blood samples were tested for the presence of BVDV antigen using the IDEXX BVDV PI X2 Kit. Positive samples were indicative of animals with an active infection. Herds were determined as having BVDV exposure by the presence of at least one animal having a positive test for active antigen (n = 4 exposed herds, n = 5 non-exposed herds). Statistical analyses were performed using the GLIMMIX procedure of SAS. Herds that had BVDV exposure during the breeding season had significantly decreased (P < 0.01) first service AI conception rates compared to herds that had no exposure (34 ± 2.3% vs. 54 ± 2.3%). Additionally, breeding season pregnancy rates were decreased (P < 0.01) in herds that had BVDV exposure compared to non-exposed herds (69 ± 3.4% vs. 80 ± 3.6%). There was no significant effect of BVDV exposure on embryonic loss (P = 0.42) or percentage of animals which lost a pregnancy and rebred by the end of the breeding season (P = 0.63). In conclusion, BVDV exposure in well vaccinated herds still had a negative effect on both first service AI conception rate and overall breeding season pregnancy success. [ABSTRACT FROM AUTHOR]

The ratio of glucogenic to lipogenic acids in ruminal VFAs can have a direct impact on nutrient utilization. The objective of this study was to compare the effects of an extended-release injectable dewormer [LongRange® (eprinomectin)] to a traditional shorter-acting injectable dewormer [Ivomec® (doramectin)] on rumen VFA profiles and blood metabolites. Ruminally cannulated lactating cows (2yr of age) were randomly allotted to one of the two dewormers (n = 5/treatment) at the time of being moved to spring grazing (day of AI). Blood samples, rumen pH, and rumen fluid were collected prior to treatment on d 0, d 15, and approximately every 30d thereafter until d 137 and analyzed by analysis of repeated measures. Fecal samples were collected at the start, middle, and end of the study to determine parasite fecal egg count. At the initiation of the study only 3 animals had any detectable parasites by fecal egg count and at the middle of the study all animals treated with the traditional dewormer had detectable parasites. Animals treated with the extended-release dewormer had no detectable parasite load throughout the study. There was no effect of treatment or treatment by time on rumen pH (P = 0.64, 0.55) or circulating NEFA concentrations (P = 0.60, 0.65) but both changed over time (P ≤ 0.01). Circulating glucose concentrations were not affected by treatment (P = 0.71) or time (P = 0.15), but there was a treatment by time interaction (P = 0.03) with glucose concentrations increased on day 32 in the extended-release dewormer. Concentrations of rumen ammonia, total VFAs, acetate, propionate, isobutyrate, butyrate, isovalerate, and valerate were not impacted by treatment (P > 0.20), but there was an effect of time (P = 0.10). In summary, controlling parasite load during a 5mo grazing season can improve nutrient utilization in cattle. [ABSTRACT FROM AUTHOR]

Parasitism decreases the nutrients available for cow and fetal/calf performance. The objective of this study was to evaluate the impact of an extended-release dewormer [LongRange® (eprinomectin)] compared to a traditional dewormer [Dectomax® (doramectin)] on fetal/calf performance. Postpartum suckled beef cows (n = 349) were grouped by age and randomly allotted to one of two treatments over a two year period 1) treatment with LongRange at AI and calves treated with Eprinex® or 2) cows and calves treated with Dectomax. In year 2, half of each treatment was switched to the opposite treatment and half remained on the same treatment to result in a 2x2 design (calf sex was included in the statistical model). Cow weight was determined at AI, d60, d135, and d365 (treatment year 2). Calves born in year 2 were weighed at time of AI and at weaning. Pregnancy rates (determined at 60 and 135 d after AI) did not differ in year 1 (P = 0.85, 0.29) or in year 2 (P = 0.44, 0.98). Both treatments lost weight from AI to d60 of the breeding season (P = 0.98); however, there was a weak tendency (P = 0.15) for LongRange cows to gain more from d60 to 135 compared to Dectomax cows. Performance did not differ from d135 to AI in year 2 (P = 0.79). Calves that were in utero during year 1 when their dam received LongRange treatment had increased weight per day of age at year 2 AI (mean calf age =58d) compared to Dectomax treatment (P = 0.05; 2.2 ± 0.09 vs 2.0 ± 0.07kg). Furthermore, year 2 treatment tended (P = 0.09) to impact weight per day of age at weaning (LongRange=1.4 ± 0.03kg, Dectomax=1.3 ± 0.02). There was no year 1 by year 2 interaction (P = 0.87). In summary, administering an extended-release dewormer at AI did not impact pregnancy success, but increased calf performance both at 50d of age and at weaning. [ABSTRACT FROM AUTHOR]

Previous studies evaluating single and multiple GnRH injections at time of CIDR removal have reported decreased interval to estrus and increased expression of estrus, and increased conception rates, respectively. Thus, the objective of this study was to compare the effects of supplementing GnRH at CIDR removal on expression of estrus and conception rates in beef heifers following the 7-d CO-Synch + CIDR protocol. Heifers (n = 1,482) from 11 herds over two years were synchronized using the 7-d CO-Synch + CIDR fixed time AI (FTAI) protocol and were randomly assigned to receive one of three treatments at CIDR removal [0 µg GnRH (0); 5 µg GnRH (5); or 5 µg at CIDR removal and 5 µg 12 h later (5 + 5)]. Expression of estrus and conception rates were analyzed using the GLIMMIX procedure of SAS with treatment as an independent variable and herd as a random effect. There was no effect of treatment on expression of estrus (P = 0.38), or AI conception rates (P = 0.85). There was an effect of estrus (P < 0.01) and a treatment × estrus interaction (P = 0.02). Animals that exhibited estrus prior to FTAI had increased (P < 0.01) conception rates compared with those that did not. Animals that exhibited estrus had increased (P < 0.01) conception rates compared with non-estrus animals in the 0 and 5 + 5 µg groups (54 ± 3% vs 34 ± 3%, and 52 ± 3% vs 36 ± 3%, respectively), but in the 5 µg group, there was no difference (P = 0.53) in conception rates between estrus and non-estrus animals (44 ± 3% vs 41 ± 3%, respectively). In conclusion, estrus expression increased pregnancy success, but supplementation with 5 or 5 + 5 µg of GnRH at CIDR removal did not improve estrus response or conception rates in beef heifers. [ABSTRACT FROM AUTHOR]

Nutritional changes immediately after insemination cause increased embryonic mortality, but the mechanisms controlling this are not well known. Our objective was to evaluate the impact of nutritional change on estrus expression, steroid concentrations, peripheral and uterine luminal fluid metabolites, and embryo quality in beef heifers. Heifers (n = 139) were assigned to one of two pre-artificial insemination (AI) dietary treatments: LOW (≤ 90% NEm) or HIGH (≥ 139% NEm). Heifers were on treatment for 33–36 days before AI (d0) when half of the heifers in each treatment were randomly reassigned to generate four treatments; HIGH-HIGH, HIGH-LOW, LOW-HIGH, and LOW-LOW. Heifers remained on treatments until embryo collection (d 6–8). Negative energy balance was achieved among LOW heifers as demonstrated by body weight loss and increased NEFA concentrations (P < 0.05). Pre-AI treatment influenced expression of estrus (P = 0.05; HIGH 80.4 ± 4.0% vs. LOW 69.4 ± 4.2%). Estradiol concentrations and interval to estrus were not affected by treatment (P > 0.55); however, progesterone concentrations were reduced among LOW compared to HIGH (3.57 ± 0.27, 4.64 ± 0.26 ng/mL, respectively; P = 0.004), and heifers maintained on the HIGH pre-AI diet had consistently greater concentrations of progesterone from d 0 to d 8 (P = 0.014). Pre-AI treatment influenced embryo stage (P = 0.05; HIGH 3.61 ± 0.32 vs. LOW 2.72 ± 0.30). Post-AI treatment affected embryo grade (P = 0.02; HIGH 1.78 ± 0.23 vs. LOW 2.64 ± 0.27). In summary, pre-AI nutrient restriction caused decreased expression of estrus, reduced progesterone concentrations after AI, and negatively impacted embryo development, while post-AI restriction hindered embryo quality. • Size of the pre-ovulatory follicle and expression of estrus is reduced following nutrient restriction. • Progesterone production after insemination is compromised in heifers experiencing negative energy balance before breeding. • Nutrient restriction prior to insemination delayed embryo development, while restriction after AI reduced embryo quality. [ABSTRACT FROM AUTHOR]