To compare 2 hormonal protocols for submission of lactating dairy cows for timed artificial insemination (TAI), nonpregnant lactating Holstein cows (n = 269) >60 d in milk were randomly assigned to each of 2 treatments to receive TAI (TAI = d 0). Cows assigned to the first treatment (Ovsynch, n = 134) received 50 microg of GnRH (d -10), 25 mg of PGF2alpha (d -3), and 50 microg of GnRH (d -1) beginning at a random stage of the estrous cycle. Cows assigned to the second treatment (Presynch, n = 135) received Ovsynch but with the addition of 2 PGF2alpha (25 mg) injections administered 14 d apart beginning 28 d (d -38 and -24) before initiation of Ovsynch. All cows received TAI 16 to 18 h after the second GnRH injection. Ovulatory response after each GnRH injection for a subset of cows (n = 109) and pregnancy status 42 d after TAI for all cows were assessed using transrectal ultrasonography. Based on serum progesterone (P4) profiles determined for a subset of cows (n = 109), P4 concentrations decreased for Presynch cows after the first 2 PGF2alpha injections, and Presynch cows had greater P4 concentrations at the PGF2alpha injection on d -3 compared with Ovsynch cows. Although the proportion of cows ovulating after the first and second GnRH injections did not differ statistically between treatments (41.1 and 69.6% vs. 35.9 and 81.1% for Ovsynch vs. Presynch, respectively), pregnancy rate per artificial insemination (PR/AI) at 42 d post TAI was greater for Presynch than for Ovsynch cows (49.6 vs. 37.3%). Parity, DIM, and body condition score (BCS) at TAI did not affect PR/AI to TAI. These data support use of this presynchronization protocol to increase PR/ AI of lactating dairy cows receiving TAI compared with Ovsynch.

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Two male, rumen fistulated crossbred Brahman-Thai native beef cattle (body weight = 400±50 kg), fed on rice straw as a source of roughage, were used as rumen fluid sources. The treatments were 2×3 factorial arrangements; two roughages (fresh cassava foliage and cassava hay) and three sulfur levels (elemental sulfur) at 0.2 (control), 0.5 and 1% of DM, respectively. The experiment revealed that the rates (c) of gas production, ammonia-nitrogen concentration, true digestibility, total concentration or molar proportions of VFA and microbial biomass were not significantly different between cassava hay and fresh cassava foliage. However, all parameters for cassava hay were higher than for fresh cassava foliage. The supplementation of 0.5% sulfur to fresh cassava foliage resulted in a significant increase in the rate of gas production, true digestibility, total concentration of VFA, microbial biomass, rate of HCN disappearance, thiocyanate appearance and cyanide percentage conversion into thiocyanate. However, there were no effects of sulfur supplementation at 0.2, 0.5 and 1% to cassava hay. The finding suggests the utilization of cassava foliage for rumen microorganisms in terms of fermentation and HCN detoxification could be improved by sulfur supplementation of 0.5% of DM.

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This research aimed to evaluate the effects of anthocyanin-extracted residue (AER) in the diet of cattle on meat oxidation during storage and on the fatty acid profiles of the meat. Sixteen male dairy cattle (average body weight 160 ± 10.6 kg) were allotted to feed in a completely randomized design (CRD) with four levels of AER supplementation, 0, 20, 40, and 60 g/kg dry matter (DM) in the total mixed ration (TMR). These TMR diets were fed ad libitum to the cattle throughout the trial. At the end of the feeding trial (125 days), all cattle were slaughtered and meat samples from the Longissimus dorsi (LD) muscle were collected to assess meat oxidation and fatty acid profile. The antioxidant effect of AER on meat oxidation was investigated during 14 days of storage based on color, myoglobin redox forms, lipid, and protein oxidation. The results showed meat from cattle fed AER had better color stability, lower oxidation of lipid, protein and myoglobin than did meat from cattle fed the control diet (0 g/kg AER). Furthermore, fatty acid profiles were affected by AER supplementation with an increase in the concentration of n-3 polyunsaturated fatty acids (PUFA). These results support the inclusion of AER supplementation as a natural antioxidant in cattle to reduce meat oxidation and increase PUFA in meat.

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