Relationships among performance, residual feed intake, and temperament assessed in growing beef heifers and subsequently as 3-year-old, lactating beef cows.

Seventy-four beef heifers were used to evaluate relationships among performance, residual feed intake (RFI), and temperament measured as growing heifers (Phase 1) and subsequently as 3-yr-old lactating beef cows (Phase 2) in the same cohort. In both phases, females were housed in a covered facility and fed similar forage-based diets, and individual feed intakes, BW, BCS, chute scores (CS), exit velocities (EV), and pen scores (PS) were collected throughout the 70-d feeding trials. In Phase 2, cows were milked on trial d 14 (lactation d 28 ± 3.5) and trial d 70 (lactation d 84 ± 3.5) to determine energy-corrected milk (ECM) production. Ultrasonic backfat thickness (BF), and ribeye area (REA) were evaluated on d 0 and 70 of the trial in Phase 2. Heifers were ranked by RFI and placed into Low (<0.5 SD mean RFI; n = 27), Medium (within ± 0.5 SD; n = 23), and High (>0.5 SD mean RFI; n = 24) RFI groups. Body weight, BCS, and ADG were similar among all RFI groups; however, daily DMI differed for all groups (P < 0.01) and was greater (10.76 ± 0.24 kg/d) for High, intermediate (9.88 ± 0.25 kg/d) for Medium, and less (8.52 ± 0.23 kg/d) for Low RFI heifers. When cow performance was analyzed based on RFI rank as heifers, BW, BCS, ADG, RFI, d 14 and d 70 ECM, BF, and REA were similar among RFI groups; however, cows that were most efficient as heifers (Low) had decreased (P < 0.05) daily DMI values (10.30 ± 0.41 kg/d) compared with cows that ranked Medium (11.60 ± 0.44 kg/d) or High (11.50 ± 0.43 kg/d) as heifers. The Pearson rank correlation between Phase 1 and 2 RFI was r = 0.13 (P = 0.30), and Pearson rank correlations showed no relationship (P > 0.1) between RFI and temperament. Phase 1 CS was negatively associated with ADG in Phase 1 (r = -0.28; P = 0.02) and 2 (r = -0.32; P = 0.01), and positively associated with d 14 (r = 0.24; P = 0.04) and 70 (r = 0.25; P = 0.03) ECM. Phase 2 CS was negatively associated with Phase 2 ADG (r = -0.29; P = 0.01) and positively associated with d 14 (r = 0.46; P = 0.001) and 70 (r = 0.33; P = 0.004) ECM. Phase 2 PS also tended to be negatively associated with DMI in Phase 1 (r = -0.20; P = 0.096) and 2 (r = -0.20; P = 0.08). In this study, heifers that were most feed efficient subsequently consumed less feed as lactating cows and maintained similar performance. Feed efficiency was not associated with differences in temperament; however, more excitable females had poorer BW gains and tended to have reduced feed intakes but produced more ECM.

Effects of vaccination on the acute-phase protein response and measures of performance in growing beef calves.

Two experiments were conducted to evaluate the influence of vaccination on the acute-phase protein (APP) reaction (Exp. 1 and 2) and measures of performance (Exp. 2) in growing beef calves. In Exp. 1, the APP reaction was assessed in newly weaned steers administered 1 of 3 treatments (n = 8 steers/treatment), consisting of 1) Mannheimia haemolytica vaccine (One Shot; Pfizer Inc., New York, NY), 2) Clostridium vaccine (UltraBac 7; Pfizer, Inc.), or 3) saline-injected control. Blood samples for the evaluation of APP concentrations were collected on d 0, 1, 3, 5, 7, 10, and 14 and steer BW measured on d 0 and 21 relative to treatment administration. Plasma concentrations of haptoglobin (Hp) increased (P < 0.05) in vaccinated but not control calves and reached a peak on d 3 and 5 for steers receiving Mannheimia haemolytica and Clostridium vaccine, respectively. Plasma concentrations of ceruloplasmin (Cp) and fibrinogen (Fb) increased (P < 0.05) in all calves after treatment administration and Fb concentrations were greatest (P < 0.01) in calves receiving Mannheimia haemolytica vaccine on d 3 and 5 compared with the other treatments. There were no treatment effects (P = 0.44) on 21-d steer ADG (0.43 kg/d; SEM = 0.082). In Exp. 2, 23 heifers were randomly assigned to 2 treatments: 1) vaccinated (Mannheimia haemolytica vaccine (One Shot; n = 12) and 2) saline control (n = 11). After vaccination, blood samples were collected for determination of APP concentrations on d 0, 3, 6, 9, 12, and 15. During this period, individual heifer DMI was measured using an automated feed intake measuring system (Model 4000E; GrowSafe Systems Ltd., Airdrie, Alberta, Canada). Initial and final shrunk BW did not differ (P > 0.36) among treatments. On d 1, plasma Cp concentrations increased (P < 0.01) sharply in vaccinated heifers but not control heifers and were greater (P < 0.05) in vaccinated vs. control heifers on d 3, 6, 9, and 12 relative to injection. Daily DMI did not differ (P = 0.66) among treatments (average = 9.1 kg/d; SEM = 0.34); however, ADG and G:F were greater (P ≤ 0.05) for control vs. vaccinated heifers (1.14 vs. 0.87 kg/d and 0.13 and 0.10 kg, respectively; SEM = 0.064 and 0.011). These data indicate that within a 2 wk period after vaccination, beef calves experience an acute-phase protein response, which may result in reduced ADG and feed efficiency.

Treatment of flaxseed to reduce biohydrogenation of α-linolenic acid by ruminal microbes in sheep and cattle, and increase n-3 fatty acid concentrations in red meat.

The objective of the study was to determine if flaxseed treated with a formaldehyde-free process could increase n-3 fatty acid (FA) concentrations in lamb and steer muscle. Twenty-four lambs (initial BW 43.8 ± 4.4 kg) were randomly divided into 4 groups for a 90-d trial. One treatment group (FLX) was fed 136 g/d of nontreated ground flaxseed; another treatment group (FLXT1) was fed 136 g/d of flaxseed treated to protect a-linolenic acid (ALA) from microbial hydrogenation; a third treatment group (FLXT2) was fed 136 g/d of a second treated flaxseed; and a fourth treatment group (CNTL) was fed corn and soybean meal with similar CP and DE levels as the other treatments. Intake of treated flaxseed raised plasma triacylglycerol concentrations of ALA more (P < 0.01) than intake of nontreated flaxseed did, but there was no difference (P = 0.65) in ALA increase between FLXT1 and FLXT2. Intake of treated flaxseed increased (P ≤ 0.05) muscle phospholipid ALA and eicosapentaenoic acid concentrations more than nontreated flaxseed did. There were no differences in muscle phospholipid n-3 concentrations between FLXT1 and FLXT2. Ten yearling steers (initial BW 437 ± 18 kg) were randomly divided into 2 groups. One group was fed ground flaxseed (0.05% of steer BW/d; FLX; n = 5) and a second group was fed treated flaxseed at the same rate (FLXT; n = 5). The 175-d trial was divided into 2 periods: high roughage, low concentrate period followed by high concentrate, low roughage period. Steers were fed rations that were formulated to be isonitrogenous, isocaloric, and isolipidic. There was no difference (P = 0.37) in increase of ALA in blood plasma of FLX and FLXT groups by the end of the first period. However, FLXT had 16% greater (P = 0.003) concentration of ALA in their plasma during the second period. Muscle phospholipid n-3 FA were not greater (P ≥ 0.55) for steers in the FLXT group. Intake of treated flaxseed raised n-3 concentrations in blood and muscle of sheep, and in blood of cattle but did not raise n-3 FA concentrations in muscle of steers. Supplementing the diets of forage-fed lambs with flaxseed treated to reduce hydrogenation of ALA by ruminal microbes can increase concentrations of n-3 FA in the muscle of lambs.

Effect of castration technique on beef calf performance, feed efficiency, and inflammatory response.

The objective of this experiment was to examine the effect of castration technique on daily feed intake (DFI), daily water intake (DWI), growth performance, residual feed intake (RFI), and inflammatory response in weaned beef calves. Seventy-five beef calves (214 ± 3.2 kg; 200 ± 26 d of age) were housed in a GrowSafe 4000 feed intake facility 7 d post weaning (15 calves/pen). Calves were offered a total mixed ration (TDN = 67.3% and CP = 12.2%, DM = 89%) for ad libitum consumption. On d 0, calves were assigned to 1 of 5 treatments (n = 15 calves/treatment): 1) steers castrated surgically pre-weaning (52 d of age; CON); 2) intact bulls (BULL); 3) bulls castrated by the Callicrate Bander on d 0 (No-Bull Enterprises LLC.; BAN); 4) bulls castrated by the Henderson Castrating Tool on d 0 (Stone Mfg & Supply Co.; HEN); and 5) bulls castrated surgically utilizing an emasculator on d 0 (SUR). Average daily gain, DFI, and DWI were recorded over 84 d. Blood was collected from a sub-sample of calves (n = 45) on d 0, 2, 6, 9, 12, and 15 relative to castration. Castration decreased (P = 0.06) ADG for castrates compared with CON from d 0 to 14 but not d 0 to 84. Daily feed intake and DWI were similar (P > 0.10) among treatments during d 0 to 84. Gain:feed was not affected by castration technique; however, RFI tended (P = 0.09) to be negative for CON and BULL compared with castrates on d 0 to 14 but not d 0 to 84. Acute phase protein analyses indicated that surgical castration (SUR or HEN) elicited a short-term inflammatory response in calves, whereas calves castrated with BAN elicited a delayed response. Calves castrated pre-weaning had improved d 0 to 14 ADG, feed intake, and inflammation response compared with calves castrated at weaning. Banding elicited a delayed negative response in ADG, DWI, and inflammation. In weaned calves, castration method did not affect performance, DFI, DWI, or inflammatory response during the 84-d trial.

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.

Body composition and estrous cyclicity responses of heifers of distinct body conditions to energy restriction and repletion.

Twenty Simmental x Angus, half-sibling, postpubertal heifers (initial BW of 443 +/- 9 kg) were allotted randomly to 2 treatments to evaluate if initial BCS affects how heifers respond to energy restriction and repletion. Dependent variables of interest were changes in BW, BCS, and reproductive status [determined by concentrations of serum progesterone (P(4))]. Empty body composition (EBC) was calculated using equations based on BCS. During a preliminary feeding period, diets were formulated so that each heifer in the designated treatment would reach a BCS of 5 (moderate condition; MOD) or a BCS of 7 (heavy condition; FAT). Once each heifer had reached the desired BCS, diets were formulated to supply 30% of NE(m) requirements until each heifer became anestrous (serum concentrations of P(4) < 1 ng/mL; restriction period). After anestrus, heifers were fed a high energy diet (1.43 Mcal/kg of DM) until estrous cycles resumed (serum concentrations of P(4) > 1 ng/mL; repletion period). Body weight, BCS, and EBC were determined on d 1 of each period, on d 43 of restriction, and d 44 of repletion, and when heifers were confirmed to have resumed estrous cycles (2 normal estrous cycles determined by P(4) > 1 ng/mL). Regression of BCS on BW determined individual BCS at anestrus and estrus. After 43 d of restriction, FAT condition heifers were heavier (P < 0.001), had greater BCS (P < 0.001), and had a greater proportion of empty body fat (P < 0.001). Heifers in FAT condition remained cyclic longer (P < 0.001) than those in MOD condition (148 vs. 61 d). In contrast, at the onset of anestrus, BW (P = 0.15), BCS (P = 0.54), and empty body fat were similar (P = 0.54) between treatments. At 44 d of repletion, BW (P = 0.46), BCS (P = 0.41), and empty body fat (P = 0.41) were similar between treatments. Heifers in both treatments recommenced estrous activity after similar (P = 0.43) number of days (54 d) of energy repletion, but near onset of estrous cycles, heifers in FAT condition were heavier (P = 0.002) and had greater BCS (P = 0.03) and empty body fat (P = 0.01) than those in MOD condition. Initial BCS influenced days to anestrus, but not BCS or EBC at onset of anestrus. Initial BCS had no effect on days to recommencement of estrous cycles, but did influence the degree of fatness required to resume estrous cycles.

Initial body condition score affects hormone and metabolite response to nutritional restriction and repletion in yearling postpubertal beef heifers.

Twenty Simmental x Angus, half-sibling, postpubertal heifers (initial BW of 443 +/- 9 kg) were allotted randomly into 2 treatment groups to evaluate if initial BCS affects response of the hypothalamic-pituitary-ovarian axis to metabolic signals elicited by energy restriction and repletion. During a preliminary feeding period, diets were formulated so that each heifer in the designated treatment would reach a BCS of 5 (moderate condition; MOD) or a BCS of 7 (heavy condition; FAT). Once each heifer had reached desired BCS, diets were formulated to supply 30% of NE(m) requirements until each heifer became anestrous (serum concentrations of progesterone < 1 ng/mL; restriction period). Blood collections took place on d 1 of each period, on d 43 of energy restriction and d 44 of energy repletion, and when heifers were confirmed to recommence estrous cycles. When heifers were cycling, their estrous cycles were synchronized to ensure hormone sampling occurred during late diestrus or early proestrus. Energy restriction resulted in decreased concentrations of LH (FAT, P = 0.02; MOD, P < 0.001), IGF-1 (FAT, P < 0.001; MOD, P = 0.003), and insulin (P < 0.001); in contrast, concentrations of GH (P < 0.001) and plasma urea nitrogen (P < 0.001) increased. During repletion, LH concentration increased (P = 0.03) in MOD condition heifers but was still less (P = 0.002) than d 1 of restriction, whereas LH concentration tended to increase in FAT heifers (P = 0.06) until it was similar (P = 0.40) to d 1 of restriction. Repletion also increased concentrations of IGF-1 (P < 0.001), insulin (P < 0.001), and glucose (P < 0.001), whereas concentrations of GH (P < 0.001), NEFA (P < 0.001), and plasma urea nitrogen (P < 0.001) decreased. For both treatments, concentrations of GH after repletion were similar (FAT, P = 0.88; MOD, P = 0.10) to those on d 1 of restriction. After repletion, FAT condition heifers had decreased concentrations of IGF-1 (P < 0.001), insulin (P < 0.05), and glucose (P < 0.001), but greater concentrations of acetate (P < 0.01) and butyrate (P < 0.05), than MOD heifers. Anestrus or resumption of estrous cycles seems to be activated gradually in response to dietary manipulation, unrelated to certain metabolite changes.

Effects of concentrated separator by-product (desugared molasses) on intake, site of digestion, microbial efficiency, and nitrogen balance in ruminants fed forage-based diets.

In Exp. 1, 4 ruminally and duodenally cannulated beef steers (444.0 +/- 9.8 kg) were used in a 4 x 4 Latin square with a 2 x 2 factorial treatment arrangement to evaluate the effects of forage type (alfalfa or corn stover) and concentrated separator byproduct (CSB) supplementation (0 or 10% of dietary DM) on intake, site of digestion, and microbial efficiency. In Exp. 2, 5 wethers (44 +/- 1.5 kg) were used in a 5 x 5 Latin square to evaluate the effects of CSB on intake, digestion, and N balance. Treatments were 0, 10, and 20% CSB (DM basis) mixed with forage; 10% CSB offered separately from the forage; and a urea control, in which urea was added to the forage at equal N compared with the 10% CSB treatment. In Exp. 1, intakes of OM and N (g/kg of BW) were greater (P < 0.01) for steers fed alfalfa compared with corn stover. Steers fed 10% CSB had greater (P < 0.08) OM and N intakes (g/kg of BW) compared with 0% CSB-fed steers. Total duodenal, microbial, and nonmicrobial flows of OM and N were greater (P < 0.01) for steers fed alfalfa compared with corn stover. Steers fed 10% CSB had increased (P = 0.02) duodenal microbial flow (N and OM) compared with 0% CSB-fed steers. Forage x CSB interactions (P < 0.01) existed for total tract N digestibility; alfalfa with or without CSB was similar (67.4 vs. 69.5), whereas corn stover with CSB was greater than corn stover without CSB (31.9 vs. -23.9%). True ruminal OM digestion was greater (P < 0.09) in steers fed alfalfa vs. corn stover (73.0 vs. 63.1%) and in steers fed 10 vs. 0% CSB (70.3 vs. 65.8%). Microbial efficiency was unaffected (P > 0.25) by forage type or CSB supplementation. In Exp. 2, forage and total intake increased (linear; P < 0.01) as CSB increased and were greater (P < 0.04) in 10% CSB mixed with forage compared with 10% CSB fed separately. Feeding 10% CSB separately resulted in similar DM and OM apparent total tract digestibility compared with 10% CSB fed mixed. Increasing CSB led to an increase (linear; P < 0.02) in DM, OM, apparent N digestion, and water intake. Nitrogen balance (g and percentage of N intake) increased (linear; P < 0.08) with CSB addition. Feeding 10% CSB separately resulted in greater (P < 0.01) N balance compared with 10% CSB fed mixed. Using urea resulted in similar (P = 0.30) N balance compared with 10% CSB fed mixed. Inclusion of CSB improves intake, digestion, and increases microbial N production in ruminants fed forage-based diets.

Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings.

To assess the effects of flax addition and flax processing on feedlot performance and carcass characteristics, 128 yearling beef heifers (360 +/- 14 kg of initial BW) were blocked by weight and assigned randomly to feedlot diets that included no flax (control), whole flax (WHL), rolled flax (RLD; 1,300 microm), or ground flax (GRD; 700 microm). Heifers were fed a growth diet (31% corn, 30% corn silage, 18% barley malt pellets, 14% alfalfa, 4% linseed meal, and 3% supplement; DM basis) for 56 d, after which they were adapted to a finishing diet (79% corn, 7% corn silage, 7% alfalfa, 4.75% linseed meal, and 2.25% supplement; DM basis). In WHL, RLD, and GRD, flax replaced all linseed meal and partially replaced corn at 8% of diet DM. All diets provided 0.5 mg of melengestrol acetate, 2,000 IU of vitamin E, and 232 mg of monensin per heifer daily. Cattle were slaughtered by block after 96, 97, and 124 (2 blocks) d on feed. At 24 h postmortem, carcass data were collected, and a portion of the loin was removed, vacuum-packaged, and aged for 14 d. After aging, 2 steaks were removed from each loin for Warner-Bratzler shear force measurement, sensory panel evaluation, and fatty acid analysis (approximately 100 g of muscle was collected). Flax inclusion (WHL, RLD, and GRD vs. control) did not affect DMI (P = 0.79), fat thickness over the 12th rib (P = 0.32), or LM area (P = 0.23). Flax inclusion increased ADG (P = 0.006), G:F (P = 0.006), and USDA yield grade (P = 0.01). Flax processing (RLD and GRD vs. WHL) increased ADG (P = 0.05), G:F (P = 0.08), and apparent dietary NEm and NEg (P = 0.003). Muscle from heifers fed flax had greater phospholipid 18:3n-3 (P < 0.001), 20:5n-3 (P < 0.001), 22:5n-3 (P < 0.001), and 22:6n-3 (P = 0.02) fractions, and greater neutral lipid 18:3n-3 (P < 0.001). Feeding 8% flax to feedlot heifers increased gain and efficiency, and processing flax increased available energy and resulted in increased efficiency of gain. Feeding 8% flax also increased levels of n-3 fatty acids in fresh beef.