Influence of Propionate Salt Levels on Young Cow Reproductive Performance

A supplementation study was conducted to evaluate level of propionate salt (Ca-propionate) on young cow performance over two years. One hundred-twenty cows were allocated to one of three treatments at calving. Propionate salt was incorporated in a protein supplement at a rate of 0, 80 or 160 g/d. Cows were individually supplemented twice weekly at 2 lbs/d. In year 1, cows had access to pasture and hay. In year 2, cows had access to a native range pasture. Blood was collected weekly and analyzed for progesterone (P4) to determine postpartum interval (≥1 ng P4/ml). Weights and body condition scores (BCS) were assigned at calving, end of supplementation, start of breeding season, and weaning. Cow weight and BCS changed over time through the study (P \u3c 0.01 but was not affected (P \u3e 0.10) by treatment. Calf weight was not different (P \u3e 0.10) between treatments. Calf weight increased through the study (P \u3c 0.01). Pregnancy rates did not differ between treatments (P \u3e 0.10 but were affected by cow age (P\u3c0.01, 77% and 100% for 2- and 3-year-olds, respectively). In year 1, the percentage of cows initiating estrous cycles before the breeding season was greater (P\u3c0.05) for cows receiving 160 g (47.6%) compared to 0 g (15.6%) of propionate salt and tended to be greater than cows receiving 80 g (P\u3c0.10, 20.0%). Based on ultrasonography, 3-year-old cows conceived earlier (P\u3c0.01, 184 d) than 2-year cows (207 d). In year 2, postpartum anestrous interval (P = 0.70), percentage of cows initiating estrous cycles before the breeding season (P = 0.54), conception rate to AI (P = 0.68), and season-long pregnancy rates (P = 0.87) were not different among treatments. In summary, propionate salt can influence reproductive performance, however, response is not consistent

Walking Distance and Performance of Drylot Developed Beef Heifers Following Being Moved to a Grazing Situation

Research has shown that heifers moved from a drylot to grass after AI have decreased weight gains and pregnancy success compared to heifers developed on range. This effect could potentially be due to inexperience in a specific grazing environment, which could result in greater time spent exploring a new environment. In this study beef heifers were moved from a drylot to spring grass at two different times and their activity compared. Heifers in a drylot walked less than heifers grazing spring forage. However, following being moved to spring forage heifers that had been adjusted to grass for about a month took fewer steps during their first four days of grazing then did the heifers that did not have previous grazing experience. Heifers without prior grazing experience also lost weight during this period. In summary, moving drylot developed heifers to spring forage affected performance and activity

The relationship between adiposity, bone density and microarchitecture is maintained in young women irrespective of diabetes status

Background: The relationship between bone health and adiposity and how it may be affected in people with chronic metabolic conditions is complex. Methods: 17 women with Type 1 diabetes mellitus (T1DM) and 9 age-matched healthy women with a median age of 22.6 yrs (range, 17.4, 23.8) were studied by 3T-MRI and MR spectroscopy to assess abdominal adiposity, tibial bone microarchitecture and vertebral bone marrow adiposity. Additional measures included DXA-based assessments of total body (TB), femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) and fat mass (FM). Results: Although women with T1DM had similar BMI and bone marrow adiposity to the controls, they had higher visceral and subcutaneous adiposity on MRI (p<0.05) and total body FM by DXA (p=0.03). Overall, in the whole cohort, a clear inverse association was evident between bone marrow adiposity and BMD at all sites (p<0.05). These associations remained significant after adjusting for age, BMI, FM, and abdominal adiposity. In addition, visceral adiposity, but not subcutaneous adiposity, showed a positive association with bone marrow adiposity (r,0.4, p=0.03), and a negative association with total body BMD (r,0.5, p=0.02). Apparent trabecular separation as assessed by MRI showed an inverse association to total body BMD by DXA (r,–0.4, p=0.04). Conclusion: Irrespective of the presence of an underlying metabolic condition, young women display a negative relationship between MRI-measured bone marrow adiposity and DXA-based assessment of bone mineral density. Furthermore, an association between bone marrow adiposity and visceral adiposity supports the notion of a common origin of these two fat depots

Comparison of Camelina Meal and Distiller’s Dried Grains with Solubles in Diet of Beef Replacement Heifers

Biofuel production from different crops yields by-product meals that are available for use as protein sources for ruminant livestock. Variation in nutrient composition among meals may result in different inclusion rates to meet nutrient needs of livestock. In this study we compared distiller’s dried grains with solubles (DDGS), a by-product of ethanol production, and camelina meal, a by-product of biodiesel production, as a protein source in hay-based diets for beef heifers before breeding. Diets were formulated to be similar in energy and protein content by altering the amount of protein source and corn in the diet. Heifers fed the two protein supplements performed similarly in both weight gain and reproductive performance. Both gain and reproduction were at very acceptable levels for beef heifers, indicating that both by-product meals are satisfactory protein sources in beef heifer diets

Comparing Pfizer GeneSTAR and Igenity PROFILE DNA tests in Crossbred Cattle

Our objective was to compare the performance of Pfizer’s GeneSTAR and Igenity’s PROFILE DNA tests in crossbred beef cattle. Hair follicles were collected from 394 crossbred steers that were part of the South Dakota State University Calf Value Discovery project (n = 145) and calves that were fed at the SDSU Southeast Research Farm (n = 249) in 2011. Hair follicles were sent to Pfizer Animal Genetics and Igenity for testing with their GeneSTAR and PROFILE DNA tests, respectively. Marbling score (100-999 scale), ribeye area, fat thickness, carcass weight, yield grade, quality grade, and % kidney, pelvic, and heart fat was collected post-harvest on all steers. Using this dataset, we first asked whether each DNA test was associated with marbling scores. If the DNA tests were not associated with marbling, then the tests may not be useful for predicting genetic merit for marbling in crossbred cattle. The GeneSTAR and PROFILE DNA tests were associated with marbling scores, but this association was not high. Second, we asked whether GeneSTAR and PROFILE DNA test results were associated with each other. If test results were not correlated, then using both DNA test results together may improve genetic predictions. GeneSTAR and PROFILE tests for tenderness were highly correlated, suggesting that DNA markers for tenderness are similar for both tests. GeneSTAR and PROFILE DNA tests for marbling and feed efficiency were not highly correlated, raising the possibility that both tests could be used jointly to improve genetic predictions for these traits. However, using both GeneSTAR and PROFILE DNA tests jointly did not appreciably improve predictions for marbling score in our dataset. We conclude that, although both GeneSTAR and PROFILE DNA tests were associated with marbling score, the correlation between these tests and marbling was low in our sample of crossbred cattle. Further, using GeneSTAR and PROFILE DNA tests for marbling and feed efficiency may improve genetic predictions for these traits, but we did not find evidence that using both tests jointly improves predictions for marbling

Importance of Estrus Expression Before Fixed-time AIon Conception Rates in Beef Cattle

Expression of estrus prior to fixed-time AI has been reported to strongly impact overall pregnancy success. Behavioral estrus is a visual indicator that a cow or heifer’s internal environment is prepared for breeding. Insemination of a cow or heifer after estrus has been expressed will yield greater pregnancy success due to adequate uterine environment, increased fertilization rates, increased accessory sperm numbers, and increased overall embryo survival. It can be difficult to analyze the effects of estrus on pregnancy success across studies due to differences in number of animals and proportion of animals exhibiting estrus per study. In order to accurately analyze such data, a meta-analysis was used to place all studies on an equal level, thus, eliminating study bias. In the present study, a meta-analysis was conducted using data available on 10,116 beef cows and heifers in 26 studies that utilized the 5 most common fixed-time AI protocols to examine the effect of expression of estrus prior to insemination on conception rates. The overall model indicated a positive effect of estrus on conception rates with cows expressing estrus before fixed-time AI having greater conception rates compared with those not exhibiting estrus. There are also numerous management factors that can influence expression of estrus. Data were available on 547 cows that were synchronized with a CIDR based fixed-time AI protocol for estrus for 2 to 4 years. Analysis of these cows indicated that days postpartum did not impact estrus expression. In contrast, Body Condition Score (BCS) influenced estrus expression with cows in a BCS of ≤ 4 having decreased expression of estrus compared to those with a BCS \u3e 4. Initiation of estrous cycles before the breeding season also influenced estrus expression, with anestrous cows having greater expression of estrus compared with estrus-cycling cows. Fixed-time AI protocols offer producers the added benefit of reduced labor needed for heat detection, but the results of this study indicate the importance of detecting an animal in estrus prior to breeding. In conclusion, among all currently recommended fixed-time AI protocols, cows expressing estrus before fixed-time AI had improved conception rates, and BCS and estrus-cycling status had the greatest influence on expression of estrus

Decreasing Magmatic Footprints of Individual Volcanos in a Waning Basaltic Field

The distribution and characteristics of individual basaltic volcanoes in the waning Southwestern Nevada Volcanic Field provide insight into the changing physical nature of magmatism and the controls on volcano location. During Pliocene-Pleistocene times the volumes of individual volcanoes have decreased by more than one order of magnitude, as have fissure lengths and inferred lava effusion rates. Eruptions evolved from Hawaiian-style eruptions with extensive lavas to eruptions characterized by small pulses of lava and Strombolian to violent Strombolian mechanisms. These trends indicate progressively decreasing partial melting and length scales, or magmatic footprints, of mantle source zones for individual volcanoes. The location of each volcano is determined by the location of its magmatic footprint at depth, and only by shallow structural and topographic features that are within that footprint. The locations of future volcanoes in a waning system are less likely to be determined by large-scale topography or structures than were older, larger volume volcanoes

Comparison of Three CIDR Based Fixed-time AI Protocols for Beef Heifers

Several effective fixed-time AI (FTAI) protocols have been developed to facilitate AI while eliminating the need for estrus detection. Among these are the 5-d CO-Synch+CIDR (5d), PG 6-d CIDR (PG-CIDR), and 14-d CIDR-PG (CIDR-PG) protocols. While each of these protocols varies in duration and approach to synchronizing estrus and ovulation, each has been reported as an effective method to facilitate FTAI in beef heifers. Therefore, the objective of this study was to compare FTAI pregnancy rates in beef heifers synchronized with these three CIDR based protocols. Virgin beef heifers (n = 801) at four locations were synchronized with one of three protocols: 1) (5-day CO-Synch + CIDR) an injection of GnRH (100 μg; i.m.) and insertion of a CIDR on d -5, PG (25 mg; i.m.) and CIDR removal on d 0 with a second injection of PG (\u3e4 h after CIDR removal) on d 0 and FTAI at 72 h after CIDR removal, 2) (PG 6-day CIDR) PG (25 mg; i.m.) on d -9, GnRH (100 μg; i.m.) and insertion of a CIDR on d -6, PG and CIDR removal on d 0, and FTAI at 66 h after CIDR removal, or 3) (14-day CIDR-PG) a 14-day CIDR insert from d -30 to -16, PG (25 mg; i.m.) on d 0, and FTAI at 66 h after PG. All heifers received an injection of GnRH (100 μg; i.m.) concurrent with FTAI. Timing of treatment initiation was offset to allow all heifers to receive FTAI concomitantly and at random. Pregnancy success was determined between 35 and 40 d after FTAI by transrectal ultrasonography. Blood samples were collected approximately 12 d before the beginning of each protocol and at the initiation of each protocol to determine estrous cycling status (77%). Data were analyzed using the GLIMMIX procedures of SAS. Fixed-time AI pregnancy success did not differ between treatments (P = 0.13; 62.5%, 56.9%, and 53.3%, for 5-day CO-Synch + CIDR, PG 6-day CIDR, and 14-day CIDR-PG; respectively) or location (P = 0.16; 51.5%, 62.7%, 56.1%, and 58.6% for location 1, 2, 3, and 4; respectively). However, heifers that had reached puberty by initiation of synchronization had greater (P \u3c 0.01) pregnancy success compared to heifers that were prepubertal (60.7% and 47.3%; respectively). In summary, all three protocols had similar FTAI pregnancy success, and puberty status had the greatest impact on pregnancy success

Uterine Environment and Pregnancy Rate of Heiferswith High Blood Urea Concentrations

Reports demonstrate that excess dietary protein significantly alters the ionic composition of uterine fluid during the luteal phase ultimately decreasing fertility. Since the early bovine embryo cannot adapt to changes in the uterine environment, changes in the concentrations of ions (pH) in the uterus can be unfavorable to embryo development and survival therefore having negative effects on fertility. In this study, heifers fed a high protein diet had elevated systemic concentrations of plasma urea nitrogen (PUN) compared to heifers fed a control diet. However, there was no deleterious effect on uterine pH or reproductive success. In summary, excess protein in a diet did increase PUNs to a concentration that has previously been reported to be detrimental to pregnancy success; however, there was no negative effect on uterine pH or pregnancy success