Effects of bismuth subsalicylate and calcium-ammonium nitrate on ruminal in vitro fermentation of bahiagrass hay with supplemental molasses.

There is a need to increase efficiency of beef production. Decreasing losses of CH4 and improving byproduct utilization are popular strategies. Two feed additives were tested to find potential solutions. Three randomized complete block design experiments were performed using batch culture systems to evaluate the effects of bismuth subsalicylate (BSS) and calcium-ammonium nitrate (CAN) on in vitro ruminal fermentation of bahiagrass hay and supplemental molasses. The first experiment contained four treatments: (1) basal substrate; (2) basal substrate with 0.75% urea (DM basis); (3) basal substrate with 1.2% CAN and 0.38% urea (DM basis); and (4) basal substrate with 2.4% CAN (DM basis). Treatments 2, 3, and 4 were isonitrogenous. The second experiment had a 4 × 3 factorial arrangement of treatments with 4 concentrations of BSS (0.00, 0.33, 0.66, and 1.00%; DM basis) and 3 concentrations of CAN (0.0, 1.2, and 2.4%; DM basis). The third experiment had the following treatments: (1) basal substrate; (2) basal substrate with 0.05% BSS (DM basis); (3) basal substrate with 0.10% BSS (DM basis); and (4) basal substrate with 0.33% BSS (DM basis). For all experiments, basal substrate consisted of Pensacola bahiagrass hay (Paspalum notatum Flüggé; 80% substrate DM) and molasses (20% substrate DM). All data were analyzed using the MIXED procedure of SAS. In Exp. 1, in vitro organic matter (OM) digestibility (IVOMD) was linearly reduced (P < 0.001) with the inclusion of CAN, and CH4, in mmol/g OM fermented, was decreased linearly (P < 0.001). The volatile fatty acid (VFA) profile was not impacted by the inclusion of nonprotein nitrogen (NPN) or CAN (P > 0.05). In Exp. 2, except for CH4 production (P < 0.05), there were no BSS × CAN interactions. Linear reductions in total gas production (P < 0.001), IVOMD (P < 0.001), and total concentration of VFA (P = 0.007) were observed with the inclusion of BSS up to 1%. The inclusion of BSS decreased H2S production in a quadratic manner (P = 0.024). In Exp. 3, IVOMD was not impacted by the inclusion of BSS (P > 0.05); however, production of H2S was linearly decreased (P = 0.004) with the inclusion of BSS up to 0.33%. In conclusion, in vitro fermentation was negatively impacted by the inclusions of BSS, up to 1%, and CAN, up to 2.4%; however, BSS decreased production of H2S when included up to 0.33% without impeding fermentation, while CAN decreased CH4 production.

Effects of polyunsaturated fatty acids supplementation on reproductive parameters associated with the performance of suckled beef cows.

To evaluate the effects of a polyunsaturated fatty acids (PUFA) supplement on reproductive parameters of suckled beef cows, two experiments were conducted. In Experiment (Exp.) 1, 60 primiparous cows were randomly assigned to one of two treatments: CTRL - 1.36 kg/day of corn gluten feed (CGF) and MEGR - 1.36 kg/day of CGF and 0.23 kg/day of calcium salts of soybean oil. Supplementation occurred from 30 days before fixed-time artificial insemination (TAI) until 7 days post-TAI. The expression of interferon-stimulated genes (ISG) was measured on days 18 and 21. Pregnancy rates were diagnosed on days 30 and 100. Treatment altered plasma fatty acid profile (P<0.05), however, did not change cow BW (P=0.52) or body condition score (BCS) (P=0.52). Treatment did not alter (P=0.12) pregnancy rates to TAI or final pregnancy rates (P=0.56). Treatments did not impact messenger RNA (mRNA) expression of the ISG OAS1 or MX2 on days 18 (P=0.67; P=0.96, respectively) or 21 (P=0.72; P=0.17, respectively). Length of gestation was greater (P=0.02) for MEGR, however, treatments did not alter calf birth weight (P=0.20). In Exp. two, 66 multiparous cows were assigned to one of two treatments: MEG - 0.65 kg/day of CGF+0.23 kg/day of calcium salts of palm oil and MEGR - 0.65 kg/day of CGF+0.23 kg/day of Ca salts of soybean oil. Cows were supplemented from 30 days prepartum to 30 days postpartum. On day 35 after TAI, pregnancy status, embryo crown-to-rump length (CRL), and plasma concentrations of pregnancy-specific protein-B (PSPB) were evaluated. Treatment altered plasma fatty acid profile (P<0.05). In addition, cows from the MEG treatment had greater BW (P<0.01) and BCS (P<0.01) than those in the MEGR treatment, as well as heavier calves at weaning (P=0.03). Treatment did not affect resumption of estrous cycle (P=0.29). There were no differences in pregnancy rates to TAI (P=0.87) or final pregnancy rates (P=0.29). No differences between treatments were detected on CRL (P=0.24) and plasma concentrations of PSPB (P=0.46). Birth weight (P=0.12) and calving distribution (P=0.52) were not altered. We concluded that PUFA supplementation altered plasma fatty acid profile, however, did not impact the remaining reproductive parameters evaluated.

Preweaning injections of bovine ST enhanced reproductive performance of Bos indicus-influenced replacement beef heifers.

A 3 yr study evaluated the effects of three preweaning injections of bovine ST, administered 14 d apart, on growth and reproductive performance of Bos indicus-influenced beef heifers. On d 0 of each year, suckling Angus × Brangus heifers (n = 15 heifers/treatment/yr) were stratified by BW (147 ± 20 kg) and age (134 ± 11 d) and randomly assigned to receive an s.c. injection of saline (SAL; 5 mL; 0.9% NaCl) or 250 mg of sometribove zinc (BST; Posilac, Elanco, Greenfield, IN) on d 0, 14, and 28. Heifers and respective dams were managed as a single group on bahiagrass (Paspalum notatum) pastures from d 0 until weaning (d 127). From d 127 to 346, heifers were grouped by treatment, allocated to bahiagrass pastures (1 pasture/treatment/yr) and fed a molasses-based supplement (2.9 kg/heifer daily; DM basis) until d 346. Blood samples were collected on d 0, 14, 28, 42, and then every 9-10 d from d 179 to 346. In yr 3, liver biopsy samples were collected on d 0, 42, and 263. Heifers were exposed to mature Angus bulls from d 263 to 346. Growth performance and physiological parameters were analyzed using the MIXED procedure, whereas reproductive variables were analyzed using the GLIMMIX procedure of SAS. Effects of treatment × year and treatment × year × time were not detected for any variable measured in this study (P ≥ 0.14), except for calving percentage (P = 0.03). Heifers assigned to BST injections had greater overall plasma concentrations of IGF-1 and ADG from d 0 to 42 (P ≤ 0.05), less ADG from d 42 to 127 (P = 0.04), but had similar BW at weaning and postweaning ADG (P ≥ 0.25) compared to SAL heifers. Heifers assigned to BST tended to achieve puberty 26 d earlier (P = 0.10), had greater percentage of pubertal heifers on d 244, 263, 284, and 296 (P ≤ 0.04), tended to have greater overall pregnancy percentage (P = 0.10), and had greater (P ≤ 0.05) calving percentages in yr 1 and 2 (but not yr 3; P = 0.68) compared to SAL heifers. Liver mRNA expression of GHR-1B and IGF-1 on d 0 and 42 did not differ between treatments (P ≥ 0.15), but was greater for BST vs. SAL heifers on d 263 (P ≤ 0.02). Hence, administering three injections containing 250 mg of sometribove zinc at 14 d intervals before weaning (between 135 and 163 d of age) induced long-term impacts on liver gene expression and may be a feasible management practice to enhance puberty and pregnancy attainment in B. indicus-influenced replacement beef heifers.

Effects of post-weaning growth rate and puberty induction protocol on reproductive performance of Bos indicus-influenced beef heifers.

A 3-yr study evaluated the effectiveness of puberty induction using exogenous reproductive hormones in beef heifers undergoing different post-weaning growth rates. On d 0 of each year, grazing Angus × Brahman heifers (60 heifers/yr) were stratified by initial BW and age (BW = 253 ± 30 kg; age = 310 ± 18 d), and randomly assigned, in a 3 × 2 factorial design, to achieve a low (LOW; 0.45 kg/d), medium (MED; 0.73 kg/d), or high (HIGH; 1.00 kg/d) growth rate from d 0 to 168 (5 heifers/pasture; 4 pastures/growth rate/yr). Dietary supplements were offered 3 times weekly (Mondays, Wednesdays, and Fridays) at 0800 h to provide 1.8, 2.9, and 4.4 kg of supplement DM per heifer daily from d 0 to 168. On d 0 of each year, 2 pastures/growth rate treatment were randomly assigned to receive (SYNC) or not (NOSYNC) a puberty induction protocol, which consisted of intravaginal controlled internal drug release (CIDR) insertion on d 65, CIDR removal on d 72, followed by 100-µg i.m. injection of GnRH on d 74, and 25-mg i.m. injection of PGF on d 84. Immediately after the puberty induction protocol, all heifers were grouped by growth rate treatment (1 group/growth rate/yr) into a single pasture and exposed to yearling Angus × Brahman bulls from d 84 to 168 (1 bull/group/yr). Interactions among growth rate and puberty induction protocol were not detected for any variable ( ≥ 0.26). Overall heifer ADG achieved only 51 to 56% of targeted ADG, and percentage of mature BW on d 84 did not differ between MED and HIGH heifers ( = 0.30), but both were heavier than LOW heifers ( < 0.01). Percentage of pubertal heifers on d 84 was greater for MED and HIGH vs. LOW heifers ( ≤ 0.05), whereas puberty induction protocol increased puberty attainment on d 84 ( < 0.01). Overall pregnancy and calving percentages after first breeding season were not affected by growth rate or puberty induction protocol ( ≥ 0.25). However, heifers calved 11 d earlier when enrolled in the puberty induction protocol ( = 0.02). In summary, puberty induction and HIGH and MED growth rates resulted in earlier attainment of puberty and pregnancy in -influenced beef heifers. However, neither growth rate or puberty induction impacted overall heifer pregnancy and calving rates on their first breeding season.

The effect of frequency of supplementing rumen-protected unsaturated fatty acids on blood serum fatty acid profiles in beef heifers and lactating cows.

The objective of this study was to determine if supplementation frequency of rumen-protected fat (RPF) influences circulating serum concentrations of fatty acids (FA), NEFA, and urea nitrogen in beef heifers and lactating cows. In Exp. 1, 12 early gestation beef heifers were supplemented 0.5 kg of corn gluten feed (CGF) daily during a 2-wk adaptation period. During the last 3 d of adaptation, blood samples were collected immediately before supplementation and then 8 and 16 h postsupplementation daily. Each heifer was then randomly assigned to 1 of 3 supplementation frequency treatments of RPF (3, 5, or 7 d/wk) for 3 wk in a 3 × 3 Latin square design with 3 periods (4 heifers per treatment per period), with each treatment receiving the same amount of RPF and CGF per wk (1.0 and 2.7 kg as fed, respectively). Blood samples were collected during the final 3 d of each supplementation period as described in the adaptation period. In Exp. 2, 18 Angus crossbred cows in early lactation were supplemented with 4.54 kg (as fed) of CGF weekly either at 3, 5, or 7 d/wk during a 2-wk adaptation period. Blood samples were collected during the last 3 d of adaptation as in Exp. 1. For the subsequent 3 wk, RPF (530, 318, and 227 g/d when supplemented) was added to the CGF supplement so that each supplementation frequency received 1.59 kg as fed/wk of RPF. Blood samples were collected during the last 3 d of supplementation as in Exp. 1. Serum FA profiles on a random subsample of 9 heifers in Exp. 1 and all animals in Exp. 2 were determined via gas chromatograph (GC), and values were analyzed using the MIXED procedure of SAS. In Exp. 1, there were no differences ( ≥ 0.53) in serum FA profile across supplementation frequencies. There was a decrease in serum 18:2, 18:1 -9 and total FA during the sampling time (time effect, < 0.02). In Exp. 2, there was treatment × time effect ( ≤ 0.001) for both 18:2 and total FA measured. The 7 d/wk frequency had a greater concentration of C18:2 and total FA at 8 h of the sampling period when compared to the other 2 frequencies. These results demonstrate that supplementation of RPF at 3, 5 or 7 d/wk resulted in no changes in serum FA profiles in growing heifers. In early lactating beef cows, there were minor time point changes in serum FA due to supplementation frequency; however, the vast majority of time points were not different, indicating no substantial changes in serum FA profiles.

Effects of molasses and crude glycerol combined in a liquid supplement on ruminal fermentation in beef steers consuming bermudagrass hay.

Two experiments were performed to evaluate the effects of 1) increasing supplementation doses of a 50:50 (as-fed) liquid supplement of molasses and crude glycerol (M:G) on ruminal fermentation parameters and blood urea nitrogen (BUN) in beef steers consuming Tifton 85 bermudagrass ( spp.) hay and 2) different proportions of molasses and crude glycerol in a liquid supplement on in vitro fermentation and gas production kinetics. For Exp. 1, 8 ruminally cannulated, Angus-crossbred steers were used in a duplicated 4 × 4 Latin square design, had ad libitum access to Tifton 85 bermudagrass hay, and were randomly assigned to 1 of 4 treatments: 1) CTRL, no supplementation; 2) SUP1, 0.45 kg/d (as fed) of 50:50 M:G; 3) SUP3, 1.36 kg/d (as fed) of 50:50 M:G; and 4) SUP5, 2.27 kg/d (as fed) of a 50:50 M:G. For Exp. 2 in vitro batch cultures were conducted to test the same treatments from Exp. 1 and effects of different proportions of a M:G mixture (100:0, 75:25, 50:50, 25:75, and 0:100) when added to a hay substrate simulating the proportions of hay and liquid supplement used in SUP5. In Exp. 1, increasing doses of liquid supplement linearly decreased ( < 0.001) concentrations of NH-N, BUN, and acetate molar proportions, whereas propionate ( = 0.002) and butyrate ( < 0.001) molar proportions increased linearly. Treatment × time interactions were observed for ruminal pH ( < 0.001), where the greatest decrease was observed at 3 h postfeeding for animals consuming SUP5 (from 6.82 at 0 h to 6.32 at 3 h). In Exp. 2, decreases in acetate molar proportions ( < 0.001) and increases ( < 0.001) in propionate and butyrate molar proportions were also observed for either increasing doses of a 50:50 mixture or increasing proportions of glycerol in the mixture. Total VFA and in vitro organic matter digestibility were increased linearly ( < 0.001) as doses of a 50:50 mixture increased. Increasing doses of 50:50 M:G to growing beef heifers consuming bermudagrass hay caused a shift in VFA profile toward increases in propionate and decreases in acetate molar proportions. This was also confirmed in vitro, as the proportions of crude glycerol increased in a molasses:crude glycerol mix. Thus, molasses and crude glycerol combined seem to be useful to enhance performance in growing cattle consuming forage-based diets.

Effects of different levels of supplementation of a 50:50 mixture of molasses:crude glycerol on performance, Bermuda grass hay intake, and nutrient digestibility of beef cattle.

Two experiments were performed to evaluate the effects of different levels of supplementation with a 50:50 (as-fed) mixture of molasses:crude glycerol on animal performance, total tract digestibility of nutrients, and ruminal in situ degradability of nutrients in beef heifers and steers consuming Tifton 85 Bermuda grass (Cynodon spp.) hay. For Exp. 1, 24 Angus crossbred heifers (380 ± 31 kg BW) were used in a generalized randomized block design. For Exp. 2, 8 ruminally cannulated Angus crossbred steers (323 ± 42 kg BW) were used in a 4 × 4 duplicated Latin square design. For both experiments, animals were housed in individual pens at the University of Florida Feed Efficiency Facility, had ad libitum access to Tifton 85 Bermuda grass hay, and were randomly assigned to 1 of 4 treatments: 1) CTRL, no supplementation; 2) SUP1, 0.45 kg/d (as fed) of 50:50 mixture; 3) SUP3, 1.36 kg/d (as fed) of 50:50 mixture; and 4) SUP5, 2.27 kg/d (as fed) of a 50:50 mixture. Individual feed intake was recorded. Total DMI increased linearly (P = 0.005) as the level of supplementation increased. Hay intake ranged from 1.36 (CTRL) to 1.23% (SUP5) of BW, and was not affected (P ≥ 0.10) by liquid supplementation. Final BW was not affected by liquid supplementation ( ≥ 0.10). There was a linear increase (P = 0.027) in ADG as the liquid supplementation amounts increased. Liquid supplementation did not affect G:F (P ≥ 0.10). Apparent total tract digestibility of DM, OM, NDF, and ADF increased linearly (P < 0.001), while CP total tract digestibility decreased linearly (P = 0.002) as the level of supplementation increased. Ruminal pH was decreased linearly (P = 0.012) as the level of supplementation increased. No effect (P ≥ 0.10) of liquid supplementation was detected on lag time for NDF and ADF content of bermudagrass hay; however, rate of degradation (Kd) of NDF tended (P = 0.076) to be affected cubically by liquid supplementation. In addition, liquid supplementation linearly decreased (P < 0.05) ED of OM, CP, NDF, and ADF. In conclusion, supplementing up to 2.27 kg/d of a 50:50 mixture of molasses:crude glycerol may stimulate microbial growth and fermentative activity, thereby increasing nutrient digestibility. Increased fiber digestion, along with energy supplementation, led to increased ADG in heifers consuming Bermuda grass hay.

Effects of anti-phospholipase A(2) antibody supplementation on dry matter intake feed efficiency, acute phase response, and blood differentials of steers fed forage- and grain-based diets.

To determine whether supplementation of anti-phospholipase A antibody (aPLA) would alter voluntary DMI, feed efficiency (FE), acute-phase protein concentration, and blood differentials (BD) due to a change in diet from a forage-based to a grain-based diet, individual daily DMI was measured on 80 cross-bred steers during a 141-d period. On d 0, steers were blocked by BW and randomly assigned to receive a growing forage diet containing 1) no additive (CON; = 20), 2) inclusion of 30 mg of monensin and 8.8 mg of tylosin per kg of diet DM (MT; = 20), 3) inclusion of an aPLA supplement at 0.4% of the diet DM (0.4% aPLA; = 20), and 4) inclusion of an aPLA supplement at 0.2% of the diet DM (0.2% aPLA; = 20). On d 60, steers were transitioned into a grain-based diet (90% concentrate) over a 21-d "step-up" period while continuing to receive their supplement treatments and were maintained on the high-grain diet until the end of the trial on d 141. On d 0, 60, 81, and 141, individual shrunk BW was recorded. Blood samples were collected on d 60, 63, 65, 67, 70, 72, 74, 77, 79, 81, and 84 for determination of concentration of plasma ceruloplasmin, haptoglobin, and BD. During the growing forage-diet period, steers from the 0.2% aPLA and 0.4% aPLA treatments had lower ( < 0.05) residual feed intake (RFI; -0.12 ± 0.13 and -0.22 ± 0.13 kg/d, respectively) than steers from the CON treatment (0.31 ± 0.13 kg/d). During the grain-based diet period, the 0.2% aPLA (-0.12 ± 0.10 kg/d), 0.4% aPLA (0.36 ± 0.10 kg/d), and MT (0.10 ± 0.10 kg/d) steers had greater ( = 0.04) RFI than CON steers (-0.37 ± 0.10 kg/d). During the transition phase, white blood cell counts were greater ( = 0.04) for the 0.2% aPLA treatment (13.61 × 10 ± 0.42 × 10 cells/µL) than the 0.4% aPLA and MT treatments (12.16 × 10 ± 0.42 × 10 and 12.37 × 10 ± 0.42 × 10 cells/µL, respectively) and concentrations of lymphocytes also were greater ( = 0.01) for the 0.2% aPLA treatment (7.66 × 10 ± 0.28 × 10 cells/µL) than the 0.4% aPLA and MT treatments (6.71 × 10 ± 0.28 × 10 and 6.70 × 10 ± 0.28 × 10 cells/µL, respectively). Concentrations of plasma ceruloplasmin and haptoglobin were reduced ( < 0.05) for CON compared to aPLA steers (22.2 ± 0.83 vs. 24.4 ± 0.83 mg/dL and 0.18 ± 0.05 vs. 0.26 ± 0.05 mg/mL, respectively). Supplementation of aPLA improved FE of steers fed a forage-based growing diet but not when feeding grain-based diets. The 0.4% aPLA and MT treatments had decreased white blood cell counts and concentration of lymphocytes during the transition period compared to the 0.2% aPLA treatment, and CON steers had reduced concentrations of plasma ceruloplasmin and haptoglobin during the diet transition phase.

Inclusion of anti-phospholipase A2 antibody to backgrounding diets on performance, feed efficiency, in vitro fermentation, and the acute-phase response of growing beef calves.

In Exp. 1, individual performance and daily DMI was measured on 70 crossbred weaned calves during a 70-d period using a GrowSafe system (GrowSafe Systems Ltd., Airdrie, AB, Canada) at the University of Florida North Florida Research and Education Center Feed Efficiency Facility (FEF). Calves were fed a low-concentrate (LC) growing diet, blocked by weight and sex, and then randomly assigned to pens to receive either no additional supplement (CON; n = 35) or receive a supplement of anti-phospholipase A2 antibody (aPLA2) at an inclusion rate of 0.6% of the diet DM (n = 35). After the 70-d feed efficiency (FE) trial (Phase 1), calves were loaded into a commercial livestock trailer and were driven for approximately 1,600 km during 24 h. Upon return to the FEF (Phase 2), calves were relocated to the same pens and groups and received the same diets and treatments for 28 d. Blood samples from each calf were collected on d 0, 1, 3, 5, 7, 14, 21, and 28 relative to initiation of transportation and were analyzed for determination of concentrations of plasma ceruloplasmin and haptoglobin. In Phase 1, initial BW (242.0 ± 3.7 kg; P = 0.92), BW at d 70 (313.0 ± 4.1 kg; P = 0.79), and ADG (1.01 ± 0.02 kg; P = 0.95) were similar between treatments. However, daily DMI was greater (P = 0.01) for CON (9.18 ± 0.15 kg) than aPLA2 (8.53 ± 0.15 kg). In addition, residual feed intake was greater (P = 0.002) for CON (0.389 ± 0.110 kg/d) than aPLA2 calves (-0.272 ± 0.110 kg/d). In Phase 2, after transportation, there were no differences between treatments on BW loss due to transportation shrink (26.0 ± 0.6 kg; P = 0.86), BW at d 28 (339.0 ± 4.1 kg; P = 0.72), ADG (1.28 ± 0.03 kg/d; P = 0.72), G:F (0.164 ± 0.004; P = 0.83), and concentrations of plasma haptoglobin (0.08 ± 0.02 mg/mL; P = 0.41). However, concentrations of plasma ceruloplasmin were greater (P < 0.001) for CON calves (14.3 ± 0.3 mg/dL) compared to aPLA2 calves (13.0 ± 0.3 mg/dL). In Exp. 2, the effects of aPLA2 inclusion on LC and high-concentrate (HC) substrates on in vitro fermentation parameters were assessed. Addition of aPLA2 had no effects on in vitro fermentation parameters of LC and HC substrates. In conclusion, supplementation of aPLA2 improved FE of growing beef calves when fed LC diets in Phase 1 and addition of aPLA2 had no effect on fermentation parameters of LC and HC substrates. In addition, calves supplemented with aPLA2 had reduced concentrations of plasma ceruloplasmin after 24 h of transportation.

Using alfalfa leaf meal as a supplement in late-gestation beef heifer and nursing beef calf diets.

Two experiments were conducted to investigate using alfalfa leaf meal (ALM; 22% CP, DM basis) in beef cattle diets. In Exp. 1, a total of 24 late-gestation Angus heifers (initial BW 470 +/- 9 kg) were blocked by BW, calving date, and BCS to 1 of 4 dietary treatments in a randomized complete block design. All heifers were offered a basal hay diet (7.4% CP and 67.6% NDF, DM basis). Treatments were arranged as a 2 x 2 factorial consisting of CP supplied at 100 or 112.5% of the recommended daily intake using either soybean meal (SBM) or ALM as the supplemental protein source. Treatments were fed for an average of 100 d before calving. Total DMI was unaffected by supplemental protein source, although heifers consumed more (P < 0.001) ALM supplement than SBM supplement at the expense of hay and corn. Feeding 112.5% of recommended CP to heifers increased precalving rate of BW gain (P = 0.004) and DM digestibility (P = 0.003). Protein source did not affect DM digestibility (P = 0.17). Neither supplemental protein source nor protein amount affected changes in BCS or calving traits. In Exp. 2, replicates of treatments were conducted over 2 consecutive years at 2 locations in northern Minnesota to determine the effects of including ALM in creep-fed supplements on nursing calf performance, supplement BW gain efficiency (GF; BW gain over control/supplement intake), and cow performance. Treatments were control (no supplement), ALM supplement (58% ALM, as-fed basis), or a wheat middling- and soybean hull-based supplement (MIDD). Milk intake (estimated by the weigh-suckle-weigh technique) was similar among treatments. Creep-fed calves had greater (P < 0.001) ADG than control calves, whereas calves offered MIDD tended to have greater ADG (P = 0.05) than those offered ALM (1.38 vs. 1.30 kg/d, respectively). Calves offered MIDD had greater (P < 0.001) creep feed DMI than those offered ALM (2.6 vs. 1.3 kg/d, respectively). A year x treatment interaction was noted for GF (P = 0.02). In yr 1, GF for calves offered ALM was greater (P = 0.006) than GF for calves offered MIDD, but in yr 2, there were no differences. Alfalfa leaf meal may substitute for SBM in beef heifer wintering diets and conventional creep feed ingredients. When included in creep feed diets, ALM can result in slightly less ADG and less DMI, but supplement conversion efficiency may be increased.

Fatty acid composition of milk from multiparous Holstein cows treated with bovine somatotropin and fed n-3 fatty acids in early lactation.

Multiparous cows (n = 59) were blocked by expected calving date and previous milk yield and assigned randomly to treatments to determine effects of bovine somatotropin (bST; Posilac, Monsanto Animal Agricultural Group, St. Louis, MO) and source of dietary fat on milk fatty acid composition during the first 140 d in milk. Diets were provided from calving and included whole, high-oil sunflower seeds (SS; 10% of dietary dry matter; n-6/n-3 ratio of 4.6) as a source of linoleic acid or a mixture of Alifet-High Energy and Alifet-Repro (AF; Alifet USA, Cincinnati, OH; 3.5 and 1.5% of dietary dry matter, respectively; n-6/n-3 ratio of 2.6) as a source of protected n-3 fatty acids (15.7% 18:3, 1.3% 20:5, and 1.3% 22:6). Treatments were derived from a 2 x 2 combination of supplemental fat source (SS, AF) and with 0 (SSN, AFN) or 500 (SSY, AFY) mg of bST administered every 10 d from 12 to 70 d in milk and at 14-d intervals thereafter. Milk fatty acid composition was determined in samples collected from 32 cows (8 complete blocks) during wk 2, 8, and 20 of lactation. Data were analyzed as repeated measures using mixed model procedures to determine the effects of diet, bST, week of lactation, and their interactions. Proportions of 18:3 (4.02 vs. 3.59 +/- 0.16%), 20:5 (0.52 vs. 0.41 +/- 0.02%), and 22:6 (0.11 vs. 0.02 +/- 0.02%) were greater and the n-6/n-3 fatty acid ratio (7.40 vs. 8.80 +/- 0.30) was reduced in milk from cows fed AF compared with SS. Proportions of de novo-synthesized fatty acids increased and preformed fatty acids decreased as lactation progressed, but bST administration delayed this shift in origin of milk fatty acids. Transfer efficiency of 18:3, 20:5, and 22:6 from AF to milk fat averaged 36.2, 4.9, and 5.2%, respectively. These efficiencies increased as lactation progressed, but were delayed by bST. Apparent mammary Delta(9)-desaturase activity and milk conjugated linoleic acid (cis-9, trans-11 conjugated linoleic acid) content increased through the first 8 wk of lactation. Based on the product-to-substrate ratio of 14:1/14:0 fatty acids in milk, there was an interaction of diet and bST because bST decreased apparent Delta(9)-desaturase activity in SSY cows but increased it in AFY cows (0.10, 0.09, 0.08, and 0.09 +/- 0.01 for SSN, SSY, AFN, and AFY, respectively). Feeding Alifet-Repro increased n-3 fatty acids in milk and bST prolonged the partitioning of dietary fatty acids into milk fat.

Postpartum ovarian activity in multiparous Holstein cows treated with bovine somatotropin and fed n-3 fatty acids in early lactation.

Multiparous cows (n = 59) were blocked by expected calving date and previous 305-d mature-equivalent milk yield and assigned randomly to a 2 x 2 factorial design to determine the effects of bovine somatotropin (bST; Posilac, Monsanto Animal Agricultural Group, St. Louis, MO) and dietary fat on ovarian activity during the first 90 d in milk (DIM). Diets that included whole, high-oil sunflower seeds [SS; 10% of dietary dry matter; rich in linoleic acid (18:2)] or a mixture of Alifet-High Energy and Alifet-Repro [AF; Alifet USA, Cincinnati, OH; 3.5 and 1.5% of dietary dry matter, respectively; protected source of linolenic (18:3), eicosapentaenoic, and docosahexaenoic fatty acids] were provided from calving. Diets were isocaloric at equal intakes, but AF provided more net energy for lactation at actual intakes (1.54 vs. 1.66 Mcal/kg of dry matter). Cows received 0 or 500 mg of bST (N, Y) every 10 d from 12 to 70 DIM and at 14-d intervals from 70 to 280 DIM. Breeding was initiated after 90 DIM. Follicular dynamics, luteal growth and development (15 to 90 DIM), and plasma progesterone concentrations (1 to 90 DIM) were evaluated (3 times per week). Days to first ovulation (33.6 +/- 1.4) and incidence of anovulation at 45 or 70 DIM did not differ among treatments. Interovulatory intervals were similar among treatments (22.1 +/- 0.9 d). Incidence of estrous cycles with 2 follicular waves was greater for SSY (71.0%) and AFN (80.0%) than for other groups, but more 3-wave cycles occurred with AFY (83.3%). Growth rate of the ovulatory follicle was greater for AF than SS (1.9 vs. 2.2 +/- 0.11 mm/d) and diameter of ovulatory follicles was larger for AFN than the other treatments (17.9 vs. 15.7 +/- 0.7 mm). Area under the progesterone curve was reduced for SSY (63.2, 48.1, 55.5, and 61.4 +/- 5.1 ng.d/mL for SSN, SSY, AFN, and AFY, respectively). The number of class 1 (3 to 5 mm) follicles was decreased and the number of class 2 (6 to 9 mm) follicles was increased by bST. The number of class 2 follicles was reduced by AF. Initiation of bST administration at 12 DIM and dietary n-3 fatty acids altered ovarian activity during the first 90 DIM and could benefit reproductive performance. Dietary n-3 fatty acids interacted with bST administration in early lactation to increase the incidence of estrous cycles with 3 follicular waves. Although these changes could benefit reproductive performance, evaluation with a larger number of cows is needed to determine if these alterations improve fertility.

Effects of supplementation frequency on performance, reproductive, and metabolic responses of Brahman-crossbred females.

Two experiments were conducted to compare performance and metabolic responses of beef females consuming low-quality forages and offered an energy supplement based on fibrous byproducts daily (S7) or 3 times per week (S3) at similar weekly rates. In Exp. 1, BW gain, reproductive performance, mRNA expression of hepatic and skeletal muscle genes associated with nutritional metabolism and growth, and concentrations of blood urea nitrogen (BUN), plasma glucose, insulin, and IGF-I were assessed in 56 Brahman x Angus heifers supplemented at a daily rate of 1.0% of BW. Mean BW gain was greater (P = 0.03) for S7 compared with S3 heifers. Treatment x sampling day interactions were detected (P < 0.01) for all blood measurements. Heifers provided S7 had less daily variation in concentrations of BUN, glucose, and insulin, and frequently had greater (P < 0.05) concentrations of IGF-I compared with S3 heifers. Expression of liver IGF-I mRNA was greater (P = 0.04) for S7 heifers compared with S3 heifers. Treatment x day interactions were detected (P

Effects of supplement type on performance, reproductive, and physiological responses of Brahman-crossbred females.

Two experiments were conducted to compare the performance and physiological responses of forage-fed beef females supplemented with either a molasses-based (ML) or a citrus pulp-based (CT) supplement. In Exp. 1, BW gain, reproductive performance, and concentrations of blood urea N (BUN), plasma glucose, insulin, IGF-I, and progesterone (P4) were assessed in 60 Brahman x Angus heifers supplemented 3 times weekly with either ML or CT. Supplement intakes were formulated to be isocaloric and isonitrogenous. Reproductive performance was not affected by treatments, but mean BW gain was greater (P < 0.01) for heifers fed CT than for those fed ML (0.40 vs. 0.30 kg/d). Mean plasma concentrations of glucose, insulin, and IGF-I were greater (P < 0.05) for heifers fed CT, whereas BUN was greater (P < 0.05) for heifers fed ML. Mean plasma P4 concentration did not differ between treatments, but both groups had lower plasma P4 concentrations during days that supplements were offered (P < 0.01). In Exp. 2, forage DMI and concentrations of BUN, plasma glucose, insulin, IGF-I, and P4 were assessed in 24 Brahman x British mature cows supplemented with the same treatments described in Exp. 1. Overall forage DMI did not differ between treatments, but a day effect and a treatment x day interaction were detected (P < 0.05). Both groups consumed less forage during the days on which the supplements were offered (P < 0.01), and forage DMI for cows fed CT was less (P < 0.05) than for cows fed ML during those days. No differences were detected in any blood or plasma measurement. In addition, no differences in concentrations of P4 were detected between CT- and ML-fed cows. We concluded that CT-supplemented heifers had greater BW gain compared with ML-supplemented heifers, but no differences in reproductive performance were observed. We also observed that CT-supplemented cows had a greater variability in forage DMI compared with ML-supplemented cows.

Can physicians warn patients of potential side effects without fear of causing those side effects?

BACKGROUND: When initiating treatment, it has been shown that only one quarter of the physicians discuss potential side effects with patients. There are several possible reasons, but, in particular, many physicians are concerned that the power of suggestion may lead some patients to experience an increase in side effects if they are fully informed. Accordingly, this study was designed to determine whether providing patients with information about potential side effects of new medications increases the reported incidence of those side effects. METHODS: All clinic patients are randomly assigned to one of four firms. Two firms served as the intervention group and two served as control groups. All patients receiving new prescriptions for the angiotensin-converting enzyme inhibitors, trimethoprim/sulfamethoxazole, or nonsteroidal anti-inflammatory drugs were recruited. Patients without telephones were excluded. Intervention patients received verbal instructions and a handout describing the name, purpose, dose, and three most common side effects of the drug. Control patients received usual discharge instructions. Patients were interviewed 14 to 21 days later using a standardized questionnaire. RESULTS: There was no difference in incidence of targeted side effects for specific medications between the study groups (38% vs 37%). Study groups were similar with regard to age, sex, financial status, and type of medication prescribed. CONCLUSION: Informing patients of potential side effects prior to starting a new medication does not lead to an increased incidence of those side effects. This should not be a reason for physicians to avoid warning patients of potential side effects.