An increasingly common method to detect pregnancy in sheep is transabdominal ultrasonography. Research has shown that transabdominal ultrasonography can be accurately measured between days 33–60 of gestation. Additionally, few studies have investigated the use of ultrasonic measurements as predictors of fetal age via transabdominal ultrasound. A pilot study found that pregnancy detection can be performed as early as 31 days with an accuracy of 100% and reported that embryonic vesicle depth (EVD) could be utilized to estimate fetal age. The purpose of the present study was to further evaluate the ability of transabdominal ultrasonography measurements to predict fetal age. Estrus was synchronized in fifteen crossbred ewes, followed by natural mating over a 24h period. From weeks 3 to 9 of gestation, transabdominal ultrasonography (at 3.5 MHz) was performed twice weekly. During on farm ultrasonography, pregnancy diagnosis and fetal count were recorded, and ultrasonic images were recorded for subsequent measurement of EVD and embryonic vesicle length. Eleven out of 15 ewes were confirmed pregnant from our sample. Using the surveyreg procedure in SAS we predict day of gestation through the independent variables: average embryo vesicle depth (aveEVD), aveEVD2, average embryo vesicle length (aveEVL), and the number of fetuses. The model predicts 82% of the variation in gestational age can be explained by the independent variables. Parameter estimates for aveEVD (P < 0.0001) and aveEVL (P < 0.0286) are positive, indicating that every 1 cm increase in these measurements results in 8.9 and 1.3 day increases in gestational age, respectively. Holding other factors constant, we find embryonic vesicle depth increases at a decreasing rate (aveEVD2, P < 0.001). These results indicate gestational age can be predicted through two embryonic vesicle measurements using transabdominal ultrasonography.
The objective was to assess the effects of an extended-release eprinomectin (LongRange) on beef heifer reproductive performance when grazed on endophyte-infected tall fescue or housed on drylot. In a split-plot design, fall-born, Angus × Simmental heifers (n = 153) were stratified by BW and divided into 6 groups. Groups were randomly assigned environmental treatments: grazed endophyte-infected tall fescue (pasture) or maintained in drylot and fed alfalfa hay. Within a group, heifers were randomly assigned to LongRange (LR) or saline (control). Heifers were dewormed with oral fenbendazole (SafeGuard) to minimize parasite load before trial initiation. On d 140 and final pregnancy check, body weight (BW) and body condition score (BCS) were collected; BW was also collected at time of artificial insemination (AI). Hair coat score (HCS), fecal egg count (FEC), packed cell volume (PCV), and respiration rates (RR) were collected on d 140. Data were analyzed using the MIXED procedure of SAS. Environment × treatment effects for BW were detected (P ≤ 0.01) at d 140 and at overall pregnancy confirmation; LR increased BW to a greater magnitude in pasture than in drylot heifers. At breeding, LR increased (P = 0.01) heifer BW compared to control. On d 140, LR increased (P = 0.01) heifer BCS compared to control. On d 140, pasture heifers tended (P = 0.08) to have greater RR than drylot heifers. Heifer AI pregnancy rates were not affected (P ≥ 0.21) by treatments. Environment × treatment effects for overall pregnancy were detected (P = 0.03); LR increased overall pregnancy rate in pasture compared to drylot heifers and LR tended to increase overall pregnancy rate compared with control in pasture heifers. In conclusion, LongRange increased BW to a greater extent in pasture than in drylot and tended to increase heifer final pregnancy rate compared to control on pasture.
Objectives were to evaluate the effects of LongRange, an extended-release eprinomectin, on beef heifer performance while grazed on endophyte-infected tall fescue or housed in drylot. Fall-born, Angus × Simmental heifers (n = 153) were utilized in a split-plot design. Heifers were stratified by BW and assigned to 6 groups. Groups were randomly assigned to 1 of 2 environmental treatments: grazed endophyte-infected tall fescue (Pasture) or housed in drylot and fed alfalfa hay. Within environmental treatment groups, heifers were randomly assigned to LongRange (LR) or control (Saline). Prior to experiment initiation, heifers were treated with oral fenbendazole (SafeGuard) to minimize parasite load. Data were analyzed using the MIXED procedure of SAS. At d 0, 56, and 112, heifer BW, ADG, BCS, hair coat score (HCS), and fecal egg counts (FEC) were collected. Treatments did not affect (P ≥ 0.17) BW on d 0 and 56. On d 112, drylot heifers tended (P = 0.08) to be heavier than pasture heifers and LR increased (P = 0.01) BW. There was an interaction (P = 0.02) for ADG; LR increased ADG to a greater magnitude in pasture than drylot heifers. On d 0, 56, and 112, there was no interaction or LongRange effect (P ≥ 0.11) on BCS; however, pasture heifers had greater (P = 0.05) d 112 BCS than drylot heifers. On d 56, there was an interaction (P = 0.01) on HCS; LR decreased HCS in pasture heifers, but did not affect HCS in drylot heifers. Although treatment did not effect (P ≤ 0.33) FEC at d 0, there was an interaction (P = 0.01) observed on d 56. LongRange decreased FEC in pasture heifers but not in drylot. In conclusion, LongRange increased heifer growth performance with a greater difference for heifers grazing tall fescue, compared with heifers in drylot.
Fourteen Suffolk/Suffolk x Hampshire pregnant ewes were utilized to evaluate the effects of liquid brewers yeast on colostrum quality and the transfer of passive immunity in their offspring. Parainfluenza type 3 (PI3) vaccination was used elicit an immune response. Ewes were vaccinated with PI3 at 33 and 18 d prior to expected lambing day. Ewes were randomly assigned to one of two treatments: late gestation diet (CON) or late gestation diet supplemented with liquid brewers yeast at an average rate of 60 g DM/d (LBY). Ewes were fed treatment diets from 45 d prior to expected lambing to 3 d post lambing. Blood was collected from ewes’ via jugular venipuncture prior to vaccination and within 6 hours postpartum. Blood was collected also from the jugular vein of lambs (n = 22) at 3 d of age. Ewe and lamb blood serum was tested for Bovine Parainfluenza 3 Virus and data on anti-PI3 antibody titers was evaluated. Colostrum was collected within 4 hours postpartum and analyzed for colostral IgG concentrations using a refractometer in % Brix. A PROC GLM model was performed in SAS 9.4, where the model for ewe colostrum quality and lamb anti-PI3 titers analyses included the main effect of treatment diet. All vaccinated ewes were positive for PI3 antibodies (>64 titer) immediately prior to and post lambing. All lambs tested positive for antibody titers for PI3 with no differences between treatment (197.3 for CON and 160.8 for LBY; P = 0.43). The colostral IgG concentrations did not differ between CON (30.4% Brix) and LBY (24.6% Brix) ewes(P = 0.21). These results indicate that, although there were numerical differences, the addition of LBY to the ewes’ diet during late gestation did not significantly improve colostrum quality or passive transfer of immunity in lambs.
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