Supplementation with long-acting injectable progesterone 3 days after TAI impaired luteal function in buffaloes.

Three experiments were conducted to evaluate the effects of long-acting injectable progesterone (iP4) in buffalo cows. In Experiment 1, ovariectomized buffaloes received 300 mg (iP300) or 600 mg (iP600) of iP4, and serum P4 concentrations were evaluated. In experiment 2, three groups were compared: control or administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after timed artificial insemination (TAI). On day 16, reproductive tract was recovered for conceptus, endometrium, and corpus luteum (CL) analysis. In experiment 3, pregnancy per AI (P/TAI) and proportion of pregnancy losses were evaluated after administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after TAI in lactating buffaloes. In experiment 1, serum P4 concentrations remained over 1 ng/mL for ~ 3 days in both groups. The 300 mg dose was used in subsequent experiments. In experiment 2, CL weight and endometrial glands density were decreased, and conceptus length was increased in iP4-D3 compared to control and to iP4-D6 (P < 0.05). Transcript abundance of Prostaglandin F Receptor (FP) and ISG15 in CL and of ISG15 and MX1 in endometrium was greater in iP4-D3 when compared to control and to iP4-D6 (P < 0.05). In experiment 3, there was no difference among experimental groups for P/TAI at D30 and pregnancy losses (P > 0.1); however, iP4-D3 presented a lower P/TAI at day 60 (41.7%) when compared to control (56.8%) and iP4-D6 (57.7%; P = 0.07). In conclusion, administration iP4 at 3 days after TAI affects CL development and consequently decreases final pregnancy outcome in buffaloes.

Stair-step strategy and immunomodulatory feed ingredient supplementation for grazing heat-stressed Bos indicus-influenced beef heifers.

On day 0 of years 1 and 2, 64 Brangus crossbred heifers per year were stratified by initial body weight (BW) and age (mean = 257 ± 20 kg and 271 ± 22 d) and allocated into 16 bahiagrass (Paspalum notatum) pastures (4 heifers per pasture per yr). Treatments were randomly allotted to pastures in a 2 × 2 factorial arrangement of treatments (4 pastures per treatment per yr). Treatments consisted of concentrate dry matter (DM) supplementation at 1.50% of BW from days 0 to 100 (CON) or concentrate DM supplementation at 1.05% of BW from days 0 to 49 and 1.95% of BW from days 50 to 100 (SST). Then, each respective supplementation strategy was added or not with immunomodulatory feed ingredients from days 0 to 100 (OMN; 4 g/45 kg of BW). Heifers were assigned to an estrus synchronization protocol from days 100 to 114. Heifers detected in estrus from days 111 to 114 were inseminated (AI) 12 h after estrus detection. Heifers not detected in estrus were timed AI on day 114. All heifers were exposed to Angus bulls from days 120 to 210 (1 bull per pasture). Effects of supplementation strategy × OMN inclusion × hour were detected (P < 0.0001) only for intravaginal temperature from days 26 to 30, which were the least (P ≤ 0.03) for SST heifers offered OMN supplementation and did not differ (P ≥ 0.17) among all remaining treatments from 0830 to 1600 hours. Effects of supplementation strategy × OMN inclusion and OMN inclusion were not detected (P ≥ 0.12) for any variable, except for the percentage of heifers detected in estrus, which was greater (P = 0.01) for heifers supplemented with vs. without OMN. Total concentrate DM offered from days 0 to 100 and heifer BW on days 0 and 56 did not differ (P ≥ 0.49) between CON and SST heifers, but SST heifers were heavier (P ≤ 0.01) on days 100 and 210 compared with CON heifers. Body surface temperature on day 25 and plasma IGF-1 concentrations on day 75 were greater (P ≤ 0.04) for SST vs. CON heifers. Percentage of pubertal heifers, heifers detected in estrus, and pregnancy to AI did not differ (P = 0.36) between SST and CON heifers but the final pregnancy percentage was greater (P = 0.04) for SST vs. CON heifers. Thus, OMN supplementation decreased the intravaginal temperature of SST heifers but failed to improve their growth and reproduction, whereas the SST strategy improved body thermoregulation, growth, and final pregnancy percentage of heat-stressed Bos indicus-influenced beef heifers compared with a constant concentrate supplementation strategy.

In Bos taurus beef heifers, altering the timing of body weight (BW) growth pattern either reduced feed costs without decreasing reproduction or enhanced reproduction without increasing feed costs. Moreover, supplementation of OmniGen-AF (OMN, a patented immunomodulatory feed ingredient) decreased internal body temperature in dairy and beef B. taurus cattle, with variable impacts on growth and reproduction. Combining both nutritional strategies for Bos indicus-beef heifers developed under heat stress conditions of tropical and subtropical environments has not been reported in the literature yet and was the main objective of the present study. For 100 d before the breeding season, heifers received either a constant supplementation amount or stair-step (SST) supplementation strategy (50 d of low followed by 50 d of high supplement amount), with or without OMN inclusion. Overall, OMN supplementation alleviated the internal body temperature of heifers but did not improve their growth and reproduction, whereas the SST strategy increased BW gain and final pregnancy percentage of B. indicus-influenced beef heifers under heat stress conditions.

Effects of maternal winter vs. year-round supplementation of protein and energy on postnatal growth, immune function, and carcass characteristics of Bos indicus-influenced beef offspring.

This 2-yr study evaluated the effects of winter vs. year-round supplementation of Bos indicus-influenced beef cows on cow reproductive performance and impact on their offspring. On day 0 of each year (approximately day 122 ± 23 of gestation), 82 to 84 mature Brangus cows/yr were stratified by body weight (BW; 475 ± 67 kg) and body condition score (BCS; 4.85 ± 0.73) and randomly assigned to 1 of 6 bahiagrass (Paspalum notatum) pastures (13 to 14 cows/pasture). Treatments were randomly assigned to pastures consisting of winter supplementation with molasses + urea (WMOL), or year-round supplementation with molasses + urea (YMOL) or wheat middling-based range cubes (YCUB). Total yearly supplement DM amount was 272 kg/cow and supplements were formulated to be isocaloric and isonitrogenous (75% TDN and 20% CP). On day 421 (weaning; approximately 260 ± 24 d of age), 33 to 35 steers/yr were vaccinated against parainfluenza-3 (PI3) and bovine viral diarrhea virus type 1 (BVDV-1) and transported 1,193 km to a feedlot. Steers were penned according to maternal pasture and managed similarly until slaughter. Data were analyzed using the MIXED and GLIMMIX procedures of SAS. On day 217 (start of breeding season), BCS was greater (P = 0.01) for YMOL than WMOL cows, whereas BCS of YCUB did not differ (P ≥ 0.11) to both WMOL and YMOL cows. The percentage of cows that calved, calving date, birth BW, and preweaning BW of the first offspring did not differ (P ≥ 0.22) among maternal treatments. Plasma cortisol concentrations were greater (P ≤ 0.001) for YCUB steers at feedlot arrival (day 422) than WMOL and YMOL steers. Moreover, YCUB steers had greater (P = 0.02) and tended (P = 0.08) to have greater plasma concentrations of haptoglobin compared to WMOL and YMOL steers, respectively. Antibody titers against PI3 and BVDV-1 viruses did not differ (P ≥ 0.25) among maternal treatments. Steer BW at feedlot exit was greater (P ≤ 0.05) for YMOL and WMOL than YCUB steers. However, feedlot DMI did not differ (P ≥ 0.37) by maternal treatment. Hot carcass weight, yield grade, LMA, and marbling did not differ (P ≥ 0.14) among maternal treatments. Percentage of steers that graded low choice was enhanced (P ≤ 0.05) for WMOL and YCUB than YMOL steers. Maternal year-round supplementation of range cubes or molasses + urea either did not impact or decrease growth, immune function, and carcass characteristics of the offspring when compared with maternal supplementation of molasses + urea during winter only.

Timing of maternal supplementation of dried distillers grains during late gestation influences postnatal growth, immunocompetence, and carcass characteristics of Bos indicus-influenced beef calves.

This 2-yr study investigated the timing of dried distillers grains (DDG) supplementation during the third trimester of gestation of Bos indicus-influenced beef cows and its impact on their offspring performance. On day 0 of each year (84 d before calving), Brangus cows (n = 84/yr; cow age = 8 ± 3 yr) were stratified by initial body weight (BW; 482 ± 75 kg) and body condition score (BCS; 5.3 ± 0.8) and assigned randomly to one of six bahiagrass (Paspalum notatum) pastures (experimental units; 14 cows/pasture). Treatments were assigned randomly to pasture (2 pastures/treatment/yr) and consisted of no prepartum supplementation (CON), 2 kg/d of DDG from day 0 to 42 (LATE42), or 1 kg/d of DDG from day 0 to 84 (LATE84). Following calving (day 84), cow-calf pairs remained in their respective pastures, and cows were offered sugarcane molasses + urea (1.82 kg of dry matter/cow/d) from day 85 until the end of the breeding season (day 224). On day 347, steer calves (n = 38/yr; 11 to 15 steers/treatment/yr) were weaned and transported to the feedlot (1,193 km). Steers were penned according to cow prepartum pasture and managed similarly until the time of harvest. BCS at calving was greater (P < 0.01) for LATE42 and LATE84 vs. CON cows but did not differ (P = 0.16) between LATE42 and LATE84 cows. Calving date, calving percentage, and birth BW of the first offspring did not differ (P ≥ 0.22) among treatments. However, LATE42 cows calved their second offspring 8 d earlier (P = 0.04) compared with CON and LATE84 cows. At weaning (first offspring), LATE84 calves were the heaviest (P ≤ 0.05), CON calves were the lightest, and LATE42 calves had intermediate BW (P ≤ 0.05). Steer plasma concentrations of cortisol and haptoglobin and serum bovine viral diarrhea virus type-1 titers did not differ (P ≥ 0.21) between treatments. Steer serum parainfluenza-3 titers were greater (P = 0.03) for LATE42 vs. CON steers, tended to be greater (P = 0.10) for LATE84 compared with CON steers, and did not differ (P = 0.38) between LATE42 and LATE84 steers. Steer feedlot BW, average daily gain, dry matter intake, and hot carcass weight did not differ (P ≥ 0.36) between treatments. Marbling and the percentage of steers grading choice were greater (P ≤ 0.04) for LATE42 vs. CON steers, whereas LATE84 steers were intermediate. In summary, different timing of DDG supplementation during the third trimester of gestation could be explored to optimize cow BCS and offspring preweaning growth and carcass quality.

This 2-yr study evaluated the effect of the timing of dried distillers grains (DDG) supplementation during the last trimester of gestation in Bos indicus-influenced beef cows and the subsequent impact on their offspring. Brangus cows were allocated to one of the three prepartum treatments consisting of no prepartum supplementation, 2 kg/d of DDG for the first half of the last trimester of gestation, or 1 kg/d of DDG for the entire length of the last trimester of gestation. Prepartum supplementation, regardless of supplementation length, improved cow body condition scores at the time of calving. Calf birth weights were not affected by prepartum maternal treatment. Calves born to cows that received prepartum supplementation had greater weaning weight compared with no prepartum supplementation. However, weaning weights were improved to the greatest extent when calves were born to cows that received supplementation for the entire length of late gestation. Steer antibody response to parainfluenza-3 was improved with prepartum maternal supplementation, regardless of supplementation length. Furthermore, concentrating the total amount of supplement offered to the first half of the last trimester of gestation improved marbling and increased the percentage of steers grading choice compared with no prepartum supplementation or supplementation during the entire last trimester.

Supplementation with sunflower seed increases circulating cholesterol concentrations and potentially impacts on the pregnancy rates in Bos indicus beef cattle.

We aimed to evaluate the effect of supplementation with sunflower seed on blood concentrations of progesterone and cholesterol and on the pregnancy rate in beef cattle subjected to timed artificial insemination (TAI) and timed embryo transfer (TET). In experiment 1, cows were received 22-day supplements containing (sunflower, n = 66) sunflower seed or not (control, n = 67) immediately after a progesterone/estradiol-based TAI protocol (Day 0). The cholesterol concentration on Day 21 and the pregnancy rate were greater (P < 0.03) in the sunflower group (148.2 ± 6.1 mg/dL and 66.7%) than those in the control group (116.0 ± 6.4 mg/dL and 47.8%). In experiment 2, heifers received an in vitro-produced embryo 7 days after the expected time of the synchronized ovulation. Heifers were separated into two supplementation groups (sunflower, n = 106 and control, n = 111) for 22 days. The plasma progesterone concentration on Day 7 was not different between the groups. However, on Day 19, the plasma progesterone concentration was greater (P < 0.0001) in the sunflower group (5.8 ± 0.4 ng/mL) than that in the control group (3.5 ± 0.4 ng/mL). A greater (P < 0.05) cholesterol concentration was observed in the sunflower group than that in the control group on Days 7 (306.0 ± 11.6 vs. 277.1 ± 11.9 mg/dL, respectively) and 19 (260.5 ± 8.0 vs. 232.0 ± 8.0 mg/dL, respectively). The pregnancy rate was greater (P = 0.01) in the sunflower-treated heifers (55.7%) than that in control-treated heifers (36.9%). Results indicate that sunflower seed supplementation increases the circulating cholesterol concentrations and potentially impacts the pregnancy rate in suckled beef cattle subjected to TAI or TET.

In vitro PGF2alpha production by endometrium and corpus luteum explants from pregnant and nonpregnant diestrus bitches and placental explants from pregnant bitches.

To better understand the process of slow luteal regression of the nonpregnant cycle in dogs and the acute luteolysis that occurs prepartum, the present study investigated in vitro PGF2alpha production by the endometrium, corpus luteum and placental explants obtained at known times of the cycle from pregnant bitches (days 63, 64 and immediately postpartum; day 0 = estimated day of the ovulatory LH surge) and from nonpregnant diestrus bitches (approximately days 65, 75 and 85). Both basal PGF2alpha production and its production in the presence of the protein kinase C (PKC) stimulator 12,13-phorbol dibutyrate (PDBu) were determined. For PDBu-supplemented incubations, mean PGF2alpha production (pg/mL/mg/6 h) by endometrium explants of the nonpregnant bitches in late diestrus was highest on day 65 (205 +/- 87) and reduced to low levels (38 +/- 17 and 11 +/- 11) on days 75 and 85, respectively. The production by corpus luteum explants from these bitches was significantly less on day 65 (46 +/- 14) than that of the day 65 endometrium explants, and was slightly increased on day 85 (103 +/- 52). The corresponding mean PGF2alpha production by the endometrium explants of pregnant bitches was on average much greater (i.e., two to three-fold) compared to nonpregnant bitches (P < 0.01) and involved high concentrations at day 64 (1523 +/- 467) and postpartum, compared to somewhat lower levels on day 63 (830+/-65); luteal PGF production (165 +/- 4) was also higher than in nonpregnant bitches around day 65. For pregnant bitches, PGF production per gram of tissue in the endometrium explants was greater than for the CL or placenta explants (180 +/- 37). Therefore, the endometrium of the pregnant bitch has an increased capability to produce PGF2alpha immediately prepartum, which on a tissue weight basis, exceeds that of either corpora lutea or the placenta. However, assuming a larger mass of placental tissue in vivo, we inferred that the placenta may contribute substantially to peripheral PGF concentrations.