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The objective of this study was to evaluate the impact of early progesterone removal on pregnancy rates to fixed-time artificial insemination (FTAI) in presynchronized beef cows. Postpartum beef cows (n = 882) were randomly assigned to 1 of 2 treatments: 1) 7&7 Synch: cows received a controlled internal drug release insert (CIDR) and a 25-mg injection of prostaglandin F2α on day 0, 100⯵g of GnRH on day 7, a second injection of prostaglandin F2α (PG2) at CIDR removal on day 14, and a second injection of GnRH at FTAI 60-66â¯h after PG2 (day 17); 2) 7&6 Synch: cows received the same treatment as 7&7 Synch; however, CIDR removal occurred in conjunction with PG2 on day 13, while FTAI remained at 60-66â¯h after CIDR removal (day 16). Ovarian ultrasonography was performed to determine follicle diameter at PG2 and FTAI in a subset of cows (n = 40). Cows exposed to the 7&7 Synch tended to have larger follicle diameter at PG2 compared with 7&6 Synch cows (P = 0.09); however, there were no differences in follicle diameter at FTAI. No differences were determined between treatments for the expression of estrus (7&7 Synch: 61.6 ± 5.30; 7&6 Synch: 54.1 ± 5.45; P = 0.31) or pregnancy rates to FTAI (7&7 Synch: 60.8 ± 3.83; 7&6 Synch: 57.0 ± 3.84; P = 0.42). In conclusion, early removal of progesterone did not impact pregnancy rates in presynchronized beef cows.
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Sincronización del Estro , Inseminación Artificial , Folículo Ovárico , Periodo Posparto , Índice de Embarazo , Progesterona , Animales , Femenino , Bovinos/fisiología , Embarazo , Progesterona/farmacología , Progesterona/administración & dosificación , Progesterona/sangre , Sincronización del Estro/efectos de los fármacos , Sincronización del Estro/métodos , Folículo Ovárico/efectos de los fármacos , Folículo Ovárico/fisiología , Inseminación Artificial/veterinaria , Estro/efectos de los fármacos , Estro/fisiología , Dinoprost/farmacología , Dinoprost/administración & dosificación , Hormona Liberadora de Gonadotropina/farmacología , Hormona Liberadora de Gonadotropina/administración & dosificaciónRESUMEN
The objective of this study was to evaluate the effects of injectable trace minerals (ITM) administrations at strategic moments in the beef cattle production cycle. At calving, 50 primiparous cows (Angusâ ×â Hereford) and their calves were randomly assigned to 1 of 2 treatments: 1) ITM: cattle assigned to the ITM treatment received an ITM injection at calving and a subsequent administration at breeding (cattle over 2 yr: 1.0 mL/90 kg body weight [BW]; calves: 1.0 mL/45 kg BW); or 2) Control: cattle assigned to the control treatment were administered with saline following the same procedure as the cattle assigned to the ITM treatment. Body weight, blood, and liver samples were collected from dams and calves at multiple time points to evaluate the growth and mineral status of cow-calf pairs. All variables were analyzed using the MIXED procedure of SAS. A treatment effect (Pâ =â 0.02) was observed for Cu liver concentration of primiparous cows at breeding. Cows assigned to ITM treatment had greater Cu status than cohorts assigned to Control treatment. No treatment effects were observed for the mineral status or growth of calves. The administration of ITM to primiparous cows enhanced Cu status when grazing Cu forages scarce of Cu.
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The objective of this study was to evaluate the effects of electrolyte solution supplementation on the performance and physiological responses of beef calves during a 45-d preconditioning phase. Forty Angusâ ×â Hereford steers (230.4â ±â 4.8 kg body weight [BW]) were sorted into 20 pens (2 steers/pen) following weaning (day 0). Treatments were randomly assigned to pens: (1) control: access to water only and (2) electrolyte: access to water and electrolyte solution supplementation (10% of total daily water intake) from days 1 to 14. Calf BW and blood samples were collected on days 0, 1, 3, 7, 14, 21, and 44 of the study. Blood samples were analyzed for sodium, potassium, albumin, haptoglobin, ceruloplasmin, and cortisol. All variables were analyzed using the MIXED procedure of SAS. Electrolyte solution consumption was estimated at 0.70 kg/calf daily (SEMâ ±â 0.21). Calves assigned to the Electrolyte treatment had greater water and total liquid intake than control (Pâ <â 0.05). No effects of treatment were observed on ADG or BW (Pâ >â 0.05). Effects of day (Pâ <â 0.004), but not treatment or treatmentâ ×â day were observed for sodium, potassium, albumin, cortisol, ceruloplasmin, and haptoglobin. Electrolyte solution supplementation during the preconditioning period did not improve performance nor influenced stress-related markers, however improved liquid intake.
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The legalization of industrial hemp by the 2018 Farm Bill in the United States has driven a sharp increase in its cultivation, including for cannabinoid extraction. Spent hemp biomass (SHB), produced from the extraction of cannabinoids, can potentially be used as feed for dairy cows; however, it is still illegal to do so in the United States, according to the US Food and Drug Administration Center for Veterinary Medicine, due to the presence of cannabinoids and the lack of data on the effect on animals. To assess the safety of this byproduct as feed for dairy cows, late-lactation Jersey cows (245 ± 37 d in milk; 483 ± 38 kg body weight; 10 multiparous and 8 primiparous) received a basal total mixed ration (TMR) diet plus 13% alfalfa pellet (CON) or 13% pelleted SHB for 4 wk (intervention period [IP]) followed by 4 wk of withdrawal period (WP), where all cows received only the basal TMR during WP. The dry matter intake (DMI), body weight, body condition score, milk yield, milk components, and fatty acid profile, blood parameters, N metabolism, methane emission, and activity were measured. Results indicated that feeding SHB decreased DMI mainly due to the low palatability of the SHB pellet, as the cows consumed only 7.4% of the total TMR with 13.0% SHB pellet offered in the ration. However, milk yield was not affected during the IP and was higher than CON during the WP, leading to higher milk yield/DMI. Milk components were not affected, except for a tendency in decreased fat percentage. Milk fat produced by cows fed SHB had a higher proportion of oleate and bacteria-derived fatty acids than CON. The activity of the cows was not affected, except for a shorter overall lying time in SHB versus CON cows during the IP. Blood parameters related to immune function were not affected. Compared with CON, cows fed SHB had a lower cholesterol concentration during the whole experiment and higher ß-hydroxybutyric acid during the WP, while a likely low-grade inflammation during the IP was indicated by higher ceruloplasmin and reactive oxidative metabolites. Other parameters related to liver health and inflammatory response were unaffected, except for a tendency for higher activity of alkaline phosphatase during IP and a lower activity of gamma-glutamyl transferase during WP in the SHB group versus CON. The bilirubin concentration was increased in cows fed SHB, suggesting a possible decrease in the clearance ability of the liver. Digestibility of the dry matter and protein and methane emission were not affected by feeding SHB. The urea, purine derivatives, and creatinine concentration in urine was unaffected, but cows fed SHB had higher N use efficiency and lower urine volume. Altogether, our data revealed a relatively low palatability of SHB affecting DMI with minimal biological effects, except for a likely low-grade inflammation, a higher N use efficiency, and a possible decrease in liver clearance. Overall, the data support the use of SHB as a safe feed ingredient for lactating dairy cows.
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Cannabinoides , Cannabis , Enfermedades de los Bovinos , Femenino , Bovinos , Animales , Leche/metabolismo , Lactancia , Biomasa , Alimentación Animal/análisis , Digestión , Dieta/veterinaria , Ácidos Grasos/metabolismo , Peso Corporal , Cannabinoides/metabolismo , Cannabinoides/farmacología , Metano/metabolismo , Nitrógeno/metabolismo , Inflamación/veterinaria , Rumen/metabolismo , Enfermedades de los Bovinos/metabolismoRESUMEN
An analog of a bovine-appeasing substance (BAS) was previously demonstrated to have calming effects, and it could be an alternative to alleviate the stress caused by weaning. Thus, the objective of this study was to evaluate the effects of BAS administration at weaning on growth, stress, behavior, and response to vaccination of Nellore calves. Eighty-six Nellore calves (40 females and 46 males) were abruptly weaned and randomly assigned into 1 of 2 treatments: (1) saline solution (0.9% NaCl; n = 43) and (2) BAS (Secure Catte, IRSEA Group, Quartier Salignan, France; n = 43). The solutions were topically applied (5 mL/calf) to the nuchal skin area of each animal. On d 0, before treatment application, calves were vaccinated against infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI3) virus, and bovine viral diarrhea virus types 1 and 2 (BVDV-1 and 2). Calves from each treatment were kept in different pastures for 15 d (time of BAS action) and then moved to a single pasture. Body weight (BW), blood samples, and temperament in the chute (entry score, chute score, and exit score) were collected on d 0, 3, 8, 15, 51, and 100, and behavior on pasture on d 1, 2, 4, 5, 6, 7, and 9. Calves assigned to BAS vs. Saline treatment tended to have greater BW on d 15 (p = 0.10), tended to have lower entry scores on d 8 and 51 (p = 0.10), and chute scores on d 8 (p = 0.07), and had lower exit scores on d 8 (p = 0.02). Calves assigned to BAS vs. Saline treatment also had greater time grazing on d 7 and 9 (p < 0.01), eating concentrate on d 2, 5, and 6 (p = 0.05), walking on d 1, 2, 5, and 9 (p < 0.01), standing and ruminating on d 2, 7 and 9 (p < 0.01), and playing on d 2, 4, 6, 7, and 9 (p < 0.01). Furthermore, they had lower time lying on 1 and 2 (p < 0.01), standing on d 5 and 9 (p < 0.01), and vocalizing on d 1 and 2 (p < 0.01). Calves assigned to BAS vs. Saline treatment had greater serum titter concentrations of PI3 t on d 15 and 51 (p = 0.05) and BVDV-1 on d 51 (p = 0.02). However, they had lower serum concentrations of cortisol on d 3 (p = 0.03). BAS administration did not affect (p ≥ 0.12) the serum titer concentration of IBR and BVDV-2 titers or the plasma concentration of haptoglobin and ceruloplasmin. The BAS administration improved BW, reduced temperament and serum cortisol concentration, and improved behavior and response to vaccination.
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This study evaluated the growth and immune response of beef calves born from Bos indicus-influenced beef heifers provided pre- and postpartum heat abatement on pasture. On 83â ±â 4 d prepartum (day 0), 64 Brangus crossbred beef heifers (~» B. indicus) were stratified by body weight (BW; 454â ±â 37 kg) and body condition score (BCS; 6.3â ±â 0.28; scale 1 to 9), and then allocated into 1 of 16 bahiagrass pastures (1 ha and 4 heifers per pasture). Treatments were randomly assigned to pastures (8 pastures per treatment) and consisted of heifers provided (SH) or not (NSH) access to artificial shade (4.5 m2 of shade area per heifer) from 83 d prepartum to 50 d postpartum (days 0 to 133). Heifers and calves were managed similarly from day 133 until the start of the breeding season (day 203). Calves were weaned on day 203 (at 119â ±â 19 d of age), limit-fed the same drylot diet at 3.5% of BW (DM basis) days 209 to 268 (3 to 4 calves per pen; 8 pens per treatment) and vaccinated against respiratory disease pathogens on days 222 and 236. Heifer intravaginal temperatures from days 35 to 42 were lower (Pâ ≤â 0.03) for NSH vs. SH heifers from 0000 to 0800 hours but greater (Pâ ≤â 0.05) for NSH vs. SH heifers from 1100 to 1800 hours. Heifer intravaginal temperature from days 126 to 132 did not differ (Pâ =â 0.99) between NSH and SH heifers. Heifers assigned to NSH had greater respiration rates from days 20 to 96 (Pâ ≤â 0.0007), greater plasma concentration of cortisol on days 35 (Pâ =â 0.07) and 55 (Pâ =â 0.02), less plasma concentration of insulin-like growth factor 1 (IGF-1) on days 35 (Pâ =â 0.10), 55, and 133 (Pâ ≤â 0.05), and less BCS from days 55 to 203 (Pâ ≤â 0.01) compared to SH heifers. Calves born from NSH heifers had less birth BW (Pâ =â 0.05), greater overall plasma haptoglobin concentrations (Pâ =â 0.05), greater seroconversion against bovine respiratory syncytial virus on day 222 (Pâ =â 0.02), tended to have greater ADG from days 209 to 268 (Pâ =â 0.07), and had greater BW on day 268 (Pâ =â 0.05) compared to SH offspring. Plasma concentrations of cortisol and serum titers against other respiratory disease pathogens did not differ (Pâ ≥â 0.15) between NSH and SH offspring. Hence, removing maternal access to artificial shade: (1) increased prepartum intravaginal temperature and plasma concentrations of cortisol but reduced prepartum BCS and plasma concentrations of IGF-1 in grazing B. indicus-influenced beef heifers; and (2) increased post-weaning BW gain and had positive effects on humoral immune response of their offspring.
In dairy cattle, heat stress during late gestation negatively impacted offspring postnatal growth and immune function. The use of artificial shade is a management strategy that alleviates heat stress in environments with high temperatures and humidity. The effects of maternal access to artificial shade and its impacts on offspring performance have not been reported for Bos indicus influenced-beef cattle and were the main objective of the present study. From 83 d prepartum until 50 d postpartum, heifers had access or not to an artificial shade structure located centrally on their pastures. Overall, removing maternal access to artificial shade increased maternal internal body temperature and respiration rates, and reduced maternal body condition score from calving until the start of the breeding season and calf body weight at birth. However, calves born from heifers with no access to shade were remarkably heavier at the end of the drylot period and had lower plasma indicators of inflammatory response and positive effects to humoral immune response to vaccination.
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Hidrocortisona , Factor I del Crecimiento Similar a la Insulina , Embarazo , Bovinos , Animales , Femenino , Fitomejoramiento , Dieta/veterinaria , Parto , Alimentación Animal/análisisRESUMEN
This study evaluated the growth and immune function of beef calves born to cows supplemented with bakery waste containing two concentrations of crude fat. On day 0 (~90 d before calving), 108 multiparous Brangus crossbred cows were stratified by body weight (BW; 551â ±â 65 kg) and body condition score (BCS, 5.5â ±â 0.9) and randomly allocated into 1 of 18 bahiagrass (Paspalum notatum) pastures (6 cows and 4.3 ha per pasture). Treatments were randomly assigned to pastures (6 pastures per treatment) and consisted of no prepartum supplementation (NOSUP) and isocaloric and isonitrogenous supplementation of low-fat (LFAT; 6.4% crude fat) or high-fat (HFAT; 10.7% crude fat) bakery waste from days 0 to 70 (1 kg DM per cow per day). Calves were weaned on day 292 (201â ±â 17 d of age). Then, 15 heifers per treatment were randomly selected and assigned to drylot pens from days 300 to 345 and vaccinated against respiratory pathogens on days 300 and 315. Cow BCS near calving (day 70) was the least (Pâ ≤â 0.05) for NOSUP cows and did not differ (Pâ =â 0.12) between LFAT and HFAT cows. Cow BCS at the start of the breeding season (day 140) was greater (Pâ =â 0.05) for HFAT vs. NOSUP cows and intermediate (Pâ ≥â 0.35) for LFAT cows. Plasma concentrations of total polyunsaturated fatty acids in HFAT cows did not differ (Pâ ≥â 0.76) compared with LFAT cows but were greater (Pâ ≤â 0.05) compared to NOSUP cows on day 70. Final pregnancy percentage did not differ (Pâ ≥â 0.26) among treatments, but a greater percentage of HFAT cows calved (Pâ ≤â 0.05) their second offspring during the first 21 d of the calving season compared to NOSUP and LFAT cows (bred by natural service). Weaning BW was the greatest (Pâ ≤â 0.05) for LFAT and least for NOSUP calves. Maternal treatments did not impact (Pâ ≥â 0.11) postweaning growth and total DM intake of calves. Average plasma cortisol concentrations were greater (Pâ =â 0.03) for NOSUP vs. HFAT calves and intermediate for LFAT calves (Pâ ≥â 0.26). Serum titers against infectious bovine rhinotracheitis and bovine respiratory syncytial virus were greater or tended to be greater (Pâ ≤â 0.08) for HFAT vs. LFAT calves and intermediate (Pâ ≥â 0.27) for NOSUP calves at the end of preconditioning. Thus, supplemental fat concentration fed to late-gestating beef cows had variable effects on calf performance. Low-fat bakery waste led to the greatest calf preweaning growth, whereas high-fat bakery waste enhanced maternal reproduction and had minor benefits to calf humoral immune function.
This study evaluated the effect of bakery waste 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 three prepartum treatments consisting of no prepartum supplementation, 1 kg/d of bakery waste with low or high concentration of crude fat. Prepartum supplementation of bakery waste, regardless of crude fat concentration, increased maternal plasma concentrations of ω-6 fatty acids during gestation and body condition score at calving. Offspring birth weights were not affected but offspring born to cows that received prepartum supplementation of bakery waste, regardless of crude fat concentration, were heavier at weaning compared to no prepartum supplementation. However, the greatest improvements to weaning weights were observed for offspring born to cows fed low-fat vs. high-fat bakery waste. In contrast, high-fat bakery waste supplementation during late gestation alleviated physiological stress and improved humoral immune response to vaccination during preconditioning compared to low-fat bakery waste supplementation. Thus, altering the crude fat concentration of bakery waste provided to Bos indicus-influenced beef cows during the third trimester of gestation can be implemented to modulate offspring preweaning growth or postweaning immune function.
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Dieta , Paspalum , Embarazo , Bovinos , Animales , Femenino , Dieta/veterinaria , Fitomejoramiento , Suplementos Dietéticos , Reproducción , Parto , Alimentación Animal/análisisRESUMEN
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.
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Alimentación Animal , Dieta , Alimentación Animal/análisis , Animales , Bovinos , Dieta/veterinaria , Suplementos Dietéticos/análisis , Inmunidad , Fitomejoramiento , Estaciones del AñoRESUMEN
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.
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Alimentación Animal , Dieta , Alimentación Animal/análisis , Animales , Bovinos , Dieta/veterinaria , Suplementos Dietéticos , Femenino , Inmunocompetencia , Parto , Fitomejoramiento , EmbarazoRESUMEN
Wildfires are increasing in frequency and severity across the Western United States. However, there is limited information available on the impacts these fires are having on the livelihood of livestock producers and their animals. This work presents the results of a survey evaluating the direct and indirect impacts of the 2020 wildfire season on beef cattle, dairy cattle, sheep, and goat, producers in California, Oregon, and Nevada. Seventy completed surveys were collected between May and July 2021. While dairy producers reported no direct impacts from the fires, beef, sheep, and goat producers were impacted by evacuations and pasture lost to fires. Only beef producers reported losses due to burns and burn-associated deaths or euthanasia. Dairy, beef, sheep, and goat producers observed reduced conception, poor weight gain, and drops in milk production. All but dairy producers also observed pneumonia. Lower birthweights, increased abortion rates, and unexplained deaths were reported in beef cattle, sheep, and goats. This work documents the wide-ranging impacts of wildfires on livestock producers and highlights the need for additional work defining the health impacts of fire and smoke exposure in livestock, as well as the policy changes needed to support producers experiencing direct and indirect losses.
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The trace mineral requirements of grazing beef cattle are often complicated by different environmental factors, such as the lack of specific trace minerals or the presence of trace mineral antagonists in forage. Nearly every region of the world has specific implications related to trace mineral nutrition of grazing cattle. Since forage is the most significant contributor to trace mineral nutrition, it is important to consider the concentrations of trace minerals and antagonists and how they may impact the performance of cattle consuming them. This review attempts to provide an update on the trace minerals commonly found to be inadequate in forage, supplementation strategies to address deficiency including a discussion on supplemental trace mineral source, and the complications presented by mineral antagonists. Although the review focuses on beef cattle grazing systems of the United States, the information herein is derived from both extensive native range and intensive planted pasture.
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This study evaluated whether administration of lipopolysaccharide (LPS) at each trimester of gestation would alter the acute phase (APR) and metabolic responses to a postnatal LPS challenge in weaned heifers. Pregnant crossbred multiparous cows (n = 50) were randomized into prenatal immune stimulation (PIS; n = 24; administered 0.1 µg/kg BW LPS subcutaneously at 71 ± 2, 170 ± 2 and 234 ± 2 d of gestation) and saline (CON; n = 26) groups. From these treatment groups, heifer calves (n = 12 PIS and 11 CON) were identified at weaning (244 ± 3 d of age) to receive an LPS challenge. On d 0, heifers were fitted with vaginal temperature (VT) devices, jugular catheters, and moved into individual stalls. On d 1, heifers were challenged i.v. with LPS (0.5 µg/kg BW) at 0 h. Blood samples were collected and sickness behavior scores (SBS) recorded at 0.5 h intervals from -2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for cortisol, cytokines, glucose, non-esterified fatty acids (NEFA), and serum urea nitrogen (SUN) concentrations. Baseline VT was lesser in PIS heifers from -11 to -5 h pre-LPS (treatment × time: P < 0.01) compared to the CON; however, the post-LPS VT response did not differ between treatments (P = 0.89). There was a treatment × time interaction (P < 0.01) for SBS with PIS heifers having lesser SBS from 0.5 to 2 h post-LPS compared to CON. There was a treatment × time interaction (P = 0.03) for cortisol with PIS heifers having greater cortisol at 0.5, 3, 3.5, 5.5 and 6.5 h post-LPS compared to CON. There were treatment × time interactions for the post-LPS cytokine responses (P ≤ 0.05). Specifically, PIS heifers had greater TNF-α from 1.5 to 2 h, yet less TNF-α at 3 h than CON (P < 0.01), and PIS heifers had greater IFN-γ from 3.5 to 5.5 h post-LPS than CON (P < 0.01). In contrast, IL-6 was less in PIS than CON heifers from 1.5 to 8 h post-LPS (P < 0.001). Glucose concentrations were greater in PIS heifers at -1 h, but less at 2, 3 and 5.5 h compared to CON (treatment × time: P < 0.01). Serum NEFA concentrations were greater (P = 0.04) in PIS than CON heifers. There was a treatment × time interaction (P < 0.01) for SUN with PIS heifers having greater SUN concentrations at -2, -1.5, 2, 3, 6.5 and 24 h than CON. These data demonstrate that in utero exposure to multiple low doses of endotoxin has lasting physiological and immunological effects when the offspring encounter a similar postnatal immunological insult.
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Three studies were completed to evaluate the effects of Cu, Zn, and Mn source on preferential intake, trace mineral status, and rainfall-induced metal loss of salt-based mineral supplements. Mineral supplements were formulated to contain 2,500, 5,500, and 4,000 mg/kg of Cu, Zn, and Mn, respectively. Supplements differed only by source of Cu, Zn, and Mn, which were hydroxychloride, organic, or sulfate sources. In Exp. 1, the three formulations were offered simultaneously for 18 wk to preweaned beef calves (four pastures; 17 calves per pasture) within separate containers inside covered cow-exclusion areas. Consumption averaged 21 ± 2.4 g/calf daily (sum of all three sources), with a greater (P < 0.001) percentage of the total intake coming from the hydroxychloride vs. organic or sulfate sources of Cu, Zn, and Mn. In Exp. 2, the same sulfate and hydroxychloride formulations were randomly assigned to pastures (n = 4 pastures per treatment) containing 18 to 20 cow-calf pairs/pasture. Treatments were offered for 20 wk within covered areas designed to assess cow and calf intake separately. At weaning, liver biopsies were collected from four cow-calf pairs/pasture (n = 16 cows and calves per treatment). Source of Cu, Zn, and Mn had no effect on voluntary mineral intake among calves (P = 0.44) and cows (P = 0.14). Calves consuming mineral containing hydroxychloride sources of Cu, Zn, and Mn tended (P = 0.06) to have greater average daily gain over the 20-wk period compared with calves consuming sulfate sources of the same elements (1.09 vs. 1.06 kg/d; SEM = 0.013). Mineral status of cows and calves was not affected (P ≥ 0.17) by source of Cu, Zn, and Mn. In Exp. 3, each of the mineral formulations from Exp. 1 was exposed to a 10.2-cm precipitation event delivered in three equal 3.4-cm applications within a week. To accomplish this, 750 g of mineral was placed into Buchner funnels (177 cm2) on 20- to 25-µm pore filter paper. Deionized water (pH adjusted to 5.6) was poured over the mineral. Total leaching losses of Cu, Zn, and Mn were less (P < 0.001) for formulations containing hydroxychloride vs. organic and sulfate sources. These results imply that, when offered a choice, calves preferentially consume mineral supplements formulated with hydroxychloride vs. sulfate or organic sources of Cu, Zn, and Mn. In addition, hydroxychloride sources of Cu, Zn, and Mn are less susceptible to rainfall-induced leaching losses compared with sulfate and organic sources.
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A 2-yr study was conducted at the Range Cattle Research and Education Center, University of Florida - Institute of Food and Agricultural Sciences (IFAS) (Ona, FL), to evaluate differences in the metabolism of Cu and Se of Angus (Bos taurus) and Brahman (Bos indicus) cattle. Thirty-two pregnant beef cows (n = 8 Brahman and 8 Angus/yr) were enrolled in the study in the first trimester of gestation. This study consisted of three phases: 1) restriction (day 0 to 90), 2) supplementation (day 91 to 150), and 3) calving. During all three phases, cows were individually fed and housed in partially covered drylot pens. During the restriction and supplementation phases, cows were provided a 1.5 kg/d of a grain-based concentrate supplement, which was fortified with flowers of S (50 g of supplemental S/cow daily; restriction phase) or Cu and Se (100 and 3 mg/d of Cu and Se, respectively; supplementation phase). Blood and liver samples were collected from all cows at 30 d intervals and from both cows and calves within 24 h of calving. Colostrum and milk samples were collected at calving and 7 d after birth. All data were analyzed using the MIXED procedure of SAS, where cow and calf were the experimental unit. During the restriction phase, a breed × day effect (P = 0.03) was observed where Brahman had greater liver Cu concentration than Angus cows in all sampling days. For liver Se concentration, a tendency (P = 0.07) for a breed effect was observed where Angus cows tended to have greater liver Se concentration than Brahman. During the supplementation phase, breed (P < 0.001) and day (P < 0.01) effects were observed, where Brahman cows had greater liver Cu concentration than Angus. For liver Se concentration, a day effect (P < 0.001) was observed, where liver Se concentration increased (P < 0.001) from day 90 to 120 and remained unchanged (P = 0.86) until day 150. At calving, no effects of breed (P = 0.34) were observed for liver Cu concentration of cows; however, Brahman calves tended (P = 0.09) to have greater liver Cu concentration than Angus calves. For Se liver concentration at calving, Angus cows tended (P = 0.07) to have greater liver Se concentration than Brahman cows; however, no breed differences (P = 0.70) were observed for liver Se concentration of calves at birth. In summary, substantial differences in multiple indicators of Cu and Se status were observed between Angus and Brahman cattle, implying that Angus and Brahman cattle possibly have different mechanisms to maintain adequate Cu and Se status.
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Cobre , Selenio , Animales , Bovinos , Calostro , Femenino , Parto , Fitomejoramiento , EmbarazoRESUMEN
This study evaluated the effects of injectable trace minerals (ITM) on antioxidant and immune response, resistance to endoparasites, health and growth of newborn Boer kids. Forty-six Boer kids [24 males and 22 females; 3.94±1.03kg of body weight (BW); 6.2±2.4 d of age] were enrolled in the study. Kids were stratified by type of birth (twins or singlet), sex, and BW and assigned to 1 of 2 treatments: one subcutaneous injection (0.1mL/4.5kg of BW) of (1) saline solution or (2) ITM (60, 10, 5, and 15mg/mL of Zn, Mn, Se and Cu, respectively). Blood samples were collected on d 0, 7, 14, 28 and 56. Feces samples were collected on d 56 and BW on d 0, 28 and 56. Kids were checked daily for signs of diarrhea. ITM kids had greater (P<0.01) plasma concentration of superoxide dismutase and tended (P=0.06) to have greater plasma concentration of glutathione peroxidase. ITM kids had greater (P=0.05) concentration of eosinophils, but no differences (P≥0.11) were observed for other hemogram variables. The ITM application did not affect (P≥0.11) the EPG count. However, ITM kids had less (P=0.02) cumulative incidence of diarhea until d 42 (3.85 vs. 25.93±6.8% for ITM vs. Saline kids, respectively) but no differences (P>0.10) were observed after d 42. The ITM application did not affect (P≥0.40) the growth of kids (0.071 vs. 0.065±0.005kg/day for ITM vs. Saline kids, respectively). Thus, the ITM application, increased the plasma concentration of antioxidant enzymes and eosinophils, decreased the incidence of diarrhea only in the middle of the experiment, but did not affected the EPG count and growth of Boer kids.(AU)
Este estudo avaliou os efeitos de microminerais injetáveis (ITM) na resposta antioxidante e imune, resistência a endoparasitas, saúde e crescimento de cabritos Boer recém-nascidos. Quarenta e seis cabritos [24 fêmeas e 22 machos; 3,94±1,03kg de peso corporal (PC); 6,2±2,4 dias de idade] foram incluídos no estudo. Os animais foram estratificados por tipo de nascimento (gêmeos ou singular), sexo e peso ao nascimento (PN) e atribuídas a 1 de 2 tratamentos. Uma injeção subcutânea (0,1ml/4,5 de PC de (1) Solução salina ou (2) ITM (60,10,5 e 15mg/ml de Zn, Mn, Se e Cu, respectivamente). As amostras de sangue foram coletadas nos dias 0, 7, 14, 28 e 56. As amostras de fezes foram coletadas no dia 56 e PC nos dias 0, 28 e 56. Os recém-nascidos foram verificados diariamente quanto a sinais de diarreia. Os cabritos ITM apresentaram maior (P<0.01) concentração de superóxido desmutase no plasma e tenderam (P=0,06) a ter maior concentração de glutationa peroxidase no plasma. Os animais ITM apresentaram maior (P=0,05) concentração de eosinófilos, mas não foram observadas diferenças (P≥0.11) para outras variáveis do hemograma. A aplicação de ITM não afetou (P≥0.11) a contagem de EPG. No entanto, os cabritos ITM apresentaram menor incidência cumulativa de diarreia (P=0,02) ate d 42 (3,85 vs. 25,93±6,8% para animais ITM vs. animais salina, respectivamente), mas nenhuma diferença (P>0.10) foi observada após d 42. A aplicação do ITM não afetou (P≥0.40) o crescimento dos animais (0.071 vs. 0.065±0.005kg/dia para ITM vs. Salina, respectivamente). Assim, a aplicação do ITM aumentou a concentração plasmática de enzimas antioxidantes e eosinófilos, diminuiu a incidência de diarreia somente na metade do experimento, mas não afetou a contagem de OPG e crescimento de cabritos Boer recém-nascidos.(AU)
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Animales , Recién Nacido , Superóxido Dismutasa , Cabras/inmunología , Enzimas , Glutatión Peroxidasa , Inyecciones , Antioxidantes , Peso Corporal , Parto , DiarreaRESUMEN
ABSTRACT: This study evaluated the effects of injectable trace minerals (ITM) on antioxidant and immune response, resistance to endoparasites, health and growth of newborn Boer kids. Forty-six Boer kids [24 males and 22 females; 3.94±1.03kg of body weight (BW); 6.2±2.4 d of age] were enrolled in the study. Kids were stratified by type of birth (twins or singlet), sex, and BW and assigned to 1 of 2 treatments: one subcutaneous injection (0.1mL/4.5kg of BW) of (1) saline solution or (2) ITM (60, 10, 5, and 15mg/mL of Zn, Mn, Se and Cu, respectively). Blood samples were collected on d 0, 7, 14, 28 and 56. Feces samples were collected on d 56 and BW on d 0, 28 and 56. Kids were checked daily for signs of diarrhea. ITM kids had greater (P 0.01) plasma concentration of superoxide dismutase and tended (P=0.06) to have greater plasma concentration of glutathione peroxidase. ITM kids had greater (P=0.05) concentration of eosinophils, but no differences (P0.11) were observed for other hemogram variables. The ITM application did not affect (P0.11) the EPG count. However, ITM kids had less (P=0.02) cumulative incidence of diarhea until d 42 (3.85 vs. 25.93±6.8% for ITM vs. Saline kids, respectively) but no differences (P>0.10) were observed after d 42. The ITM application did not affect (P0.40) the growth of kids (0.071 vs. 0.065±0.005kg/day for ITM vs. Saline kids, respectively). Thus, the ITM application, increased the plasma concentration of antioxidant enzymes and eosinophils, decreased the incidence of diarrhea only in the middle of the experiment, but did not affected the EPG count and growth of Boer kids.
RESUMO: Este estudo avaliou os efeitos de microminerais injetáveis (ITM) na resposta antioxidante e imune, resistência a endoparasitas, saúde e crescimento de cabritos Boer recém-nascidos. Quarenta e seis cabritos [24 fêmeas e 22 machos; 3,94±1,03kg de peso corporal (PC); 6,2±2,4 dias de idade] foram incluídos no estudo. Os animais foram estratificados por tipo de nascimento (gêmeos ou singular), sexo e peso ao nascimento (PN) e atribuídas a 1 de 2 tratamentos. Uma injeção subcutânea (0,1ml/4,5 de PC de (1) Solução salina ou (2) ITM (60,10,5 e 15mg/ml de Zn, Mn, Se e Cu, respectivamente). As amostras de sangue foram coletadas nos dias 0, 7, 14, 28 e 56. As amostras de fezes foram coletadas no dia 56 e PC nos dias 0, 28 e 56. Os recém-nascidos foram verificados diariamente quanto a sinais de diarreia. Os cabritos ITM apresentaram maior (P 0.01) concentração de superóxido desmutase no plasma e tenderam (P=0,06) a ter maior concentração de glutationa peroxidase no plasma. Os animais ITM apresentaram maior (P=0,05) concentração de eosinófilos, mas não foram observadas diferenças (P0.11) para outras variáveis do hemograma. A aplicação de ITM não afetou (P0.11) a contagem de EPG. No entanto, os cabritos ITM apresentaram menor incidência cumulativa de diarreia (P=0,02) ate d 42 (3,85 vs. 25,93±6,8% para animais ITM vs. animais salina, respectivamente), mas nenhuma diferença (P>0.10) foi observada após d 42. A aplicação do ITM não afetou (P0.40) o crescimento dos animais (0.071 vs. 0.065±0.005kg/dia para ITM vs. Salina, respectivamente). Assim, a aplicação do ITM aumentou a concentração plasmática de enzimas antioxidantes e eosinófilos, diminuiu a incidência de diarreia somente na metade do experimento, mas não afetou a contagem de OPG e crescimento de cabritos Boer recém-nascidos.
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This 2-yr study evaluated the growth and puberty attainment of Bos indicus-influenced beef heifers offered 2 different postweaning concentrate supplementation amounts and delivery frequencies. On day 0 of each year, 64 Brangus crossbred heifers were stratified by initial body weight (BW) and age (mean = 244 ± 22 kg; 314 ± 17 d) and assigned into 1 of 16 bahiagrass pastures (4 heifers/pasture/yr). Treatments were randomly assigned to pastures in a 2 × 2 factorial design (4 pastures/treatment/yr) and consisted of concentrate dry matter (DM) supplementation at 1.25% or 1.75% of BW which were offered either daily (7×) or 3 times weekly (3×) for 168 d. On day 56 of each year, heifers were assigned to an estrus synchronization protocol consisting of intravaginal controlled internal drug release (CIDR) insertion on day 56, CIDR removal on day 70, i.m. injection of 25 mg of prostaglandin F2α (PGF2α) on day 86, and i.m. injection of 100 µg of gonadotropin-releasing hormone and timed-AI at 66 h after PGF2α injection (day 89). Heifers were exposed to Angus bulls from day 89 to 168 (1 bull/pasture). Pregnancy diagnosis was assessed on day 213 of each year. Supplementation amount × frequency effects were not detected (P ≥ 0.12) for any variable, except for plasma concentrations of glucose (P = 0.10) and urea nitrogen (PUN; P = 0.01). Herbage mass, herbage allowance, and nutritive value did not differ (P ≥ 0.12) among treatments. Increasing supplementation DM amount from 1.25% to 1.75% of BW increased (P ≤ 0.05) plasma concentrations of insulin-like growth factor 1 (IGF-1), overall average daily gain (ADG), final BW, percentage of pubertal heifers on day 89, pregnancy and calving percentages, and percentage of heifers calving within the first 21 d of the calving season. However, reducing the supplementation frequency from daily to 3× weekly, regardless of supplementation amount, did not impact overall pregnancy and calving percentages (P ≥ 0.42), but caused (P ≤ 0.05) fluctuations in plasma concentrations of insulin and IGF-1 and decreased (P ≤ 0.03) overall ADG, final BW, puberty attainment on days 56, 89, and 168, and percentage of heifers calving during the first 21 d of the calving season. Hence, increasing the supplement DM amount did not prevent the negative effects of reducing the frequency of supplementation (3× vs. 7× weekly) on growth and reproduction of replacement Bos indicus-influenced beef heifers.
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Bovinos/fisiología , Suplementos Dietéticos/análisis , Dinoprost/administración & dosificación , Ingestión de Alimentos , Hormona Liberadora de Gonadotropina/administración & dosificación , Reproducción/efectos de los fármacos , Animales , Peso Corporal/efectos de los fármacos , Bovinos/crecimiento & desarrollo , Sincronización del Estro , Femenino , Factor I del Crecimiento Similar a la Insulina/análisis , Factor I del Crecimiento Similar a la Insulina/genética , Masculino , Valor Nutritivo , Paspalum , Embarazo , Estaciones del Año , Maduración Sexual/efectos de los fármacosRESUMEN
A 2-yr study evaluated the growth and postvaccination immune response of beef calves born from heifers offered no supplementation or pre- and postpartum supplementation of sugarcane molasses + urea with or without methionine hydroxy analog (MHA). On day 0 of each year (57 ± 5 d prepartum), Brangus crossbred beef heifers (n = 36/yr; 20 to 22 mo of age) were stratified by their initial body weight (BW; 396 ± 24.1 kg) and body condition score (BCS; 5.6 ± 0.43) and randomly allocated into 1 of 12 bahiagrass (Paspalum notatum) pastures (3 heifers/pasture). Treatments were randomly assigned to pastures (4 pastures/treatment/yr) and consisted of no supplementation (NOSUP) and supplementation of sugarcane molasses + urea (7.2 kg of DM/heifer/wk) with (MOL+) or without (MOL-) fortification with 105 g/heifer/wk of MHA. Treatments were provided from 57 ± 5 d prepartum until 17 ± 5 d postpartum (day 0 to 74). On day 74, all heifer-calf pairs were combined and managed as a single group until the end of the breeding season (day 237). Calves were early weaned at 89 ± 5 d of age (day 147), limit-fed at 3.5% of BW (DM basis) in drylot until day 201, and vaccinated against respiratory disease pathogens on days 160 and 188. Prepartum BCS on day 44 did not differ (P = 0.26) between MOL+ and MOL- heifers but both groups had greater (P < 0.0001) BCS than NOSUP heifers. Plasma concentrations of l-methionine on day 44 were the greatest (P ≤ 0.04) for MOL+ heifers and did not differ (P = 0.40) between NOSUP vs. MOL- heifers. Calf birth BW did not differ (P = 0.13) among treatments. Calf average daily gain (ADG) from birth to day 201 did not differ (P ≥ 0.17) between MOL+ vs. MOL- calves, but both groups had greater (P ≤ 0.05) ADG from birth to day 201 than NOSUP calves. Calf postvaccination plasma concentrations of glucose, cortisol, and haptoglobin did not differ among treatments (P ≥ 0.13). However, plasma concentrations of IGF-1 on day 167 and the overall positive vaccine seroconversion did not differ (P ≥ 0.18) between MOL- and MOL+ calves, but both were greater (P ≤ 0.04) compared with NOSUP calves. Hence, maternal supplementation of sugarcane molasses + urea increased BCS at calving and offspring BW gain and response to vaccination against respiratory pathogens compared with no maternal supplementation. MHA inclusion into maternal supplements effectively increased maternal plasma l-methionine concentrations but did not enhance maternal BCS at calving and offspring growth and postvaccination immune response.
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Bovinos/fisiología , Suplementos Dietéticos/análisis , Ingestión de Energía , Vacunación/veterinaria , Animales , Peso Corporal , Cruzamiento , Bovinos/crecimiento & desarrollo , Bovinos/inmunología , Dieta/veterinaria , Femenino , Factor I del Crecimiento Similar a la Insulina/análisis , Metionina/análogos & derivados , Metionina/análisis , Melaza , Parto , Periodo Posparto , Embarazo , Distribución Aleatoria , Saccharum , Estaciones del Año , DesteteRESUMEN
The objectives of the study were to evaluate the growth, physiological parameters, and liver trace mineral status of beef heifers provided low-quality warm-season forage and different forms (meal vs. block) of trace mineral-fortified supplementation. One hundred yearling Nellore heifers were blocked by initial body weight (BW) (184 ± 2.5 kg) and randomly assigned into 1 of 20 drylot pens (5 heifers/pen). Treatments were randomly assigned to pens (5 pens/treatment) and consisted of heifers receiving: 1) a loose meal trace mineral supplement (TM; De Heus Animal Nutrition Industry); 2) free choice access to a low-moisture, cooked sugarcane molasses-based protein block (LMB); 3) isocaloric and isonitrogenous, loose meal protein supplement pair-fed to LMB supplement dry matter (DM) intake (PSPF); and (4) loose meal protein supplement offered at 0.2% of BW (PS). Supplements were formulated to achieve same daily intake of supplemental trace mineral among treatments. Hence, TM supplement was offered at 66.6% of the supplement DMI of LMB heifers. Heifers were offered free choice access to water and ground brachiaria (Brachiaria brizantha) hay from day 0 to 45. Overall average daily gain from day 0 to 45 was the least for TM heifers (P ≤ 0.05) and did not differ among LMB, PSPF, and PS heifers (P ≥ 0.60). Daily hay DMI did not differ among treatments (P ≥ 0.63). Total intake of DM and TDN were least for TM heifers (P ≤ 0.03) and did not differ (P ≥ 0.66) among LMB, PSPF, and PS heifers. Total supplemental intake of crude protein (CP) and rumen degradable protein (RDP) and total intake of CP and RDP (supplement + hay) were least for TM and greatest for PS heifers (P ≤ 0.05), and intermediate for LMB and PSPF heifers (P ≥ 0.70). Effects of treatment × day and treatment were not detected (P ≥ 0.61) for plasma concentrations of insulin-like growth factor 1 (IGF-1), and non-esterified fatty acids (NEFA). Effects of treatment were detected for plasma concentrations of PUN (P = 0.005) and tended to be detected for plasma concentrations of glucose (P = 0.08), which were least for TM heifers (P ≤ 0.03) and did not differ (P ≥ 0.17) among LMB, PSPF, and PS heifers. Trace mineral intake and liver concentrations of all trace minerals did not differ (P ≥ 0.13) among treatments. Hence, the use of LMB supplementation resulted in positive effects on growth without impacting trace mineral status compared to a loose meal trace mineral salt, and similar growth performance and trace mineral status compared to a conventional protein supplementation offered at 0.2% of body weight.
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This study evaluated the effects of gradual reduction in frequency of energy supplementation following vaccination on growth and measurements of innate and humoral immunity of beef steers. At 14-d postweaning (d 0), Angus steers (n = 42; 200 ± 5 kg of BW; 175 ± 4 d of age) were stratified by BW and age, and randomly assigned into 1 of 14 drylot pens (three steers/pen). From d 0 to 42, steers were provided ad libitum ground tall fescue hay (57% TDN, 13% CP of DM basis) and supplemented with concentrate at 1% of BW (50:50 soybean hulls and corn gluten feed; 71% TDN, 15% CP of DM basis). Treatments were randomly assigned to pens, and consisted of similar weekly concentrate DM supplementation (1% of BW multiplied by 7 d) that was divided and offered daily from d 0 to 42 (7X; 4 pens), 3 times weekly from d 0 to 42 (3X; Monday, Wednesday, and Friday; 5 pens), or daily from d 0 to 15 and then 3 times weekly from d 16 to 42 (7-3X; 5 pens). Steers were vaccinated against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3), Mannheimia haemolytica, and Clostridium on d 0 and 15. Individual shrunk BW was collected on d 0 and 42, following 12 h of feed and water withdrawal. Blood samples were collected via jugular venipuncture 4 h after concentrate supplementation on d 0, 1, 2, 3, 7, 15, 16, 17, 18, 22, and 42. Mean BW, ADG, G:F, hay DMI, and total DMI over the 42-d period did not differ among treatments (P ≥ 0.26). Plasma concentrations of cortisol and mean serum BVDV-1a titers also did not differ among treatments (P ≥ 0.35), but overall plasma haptoglobin concentrations were greater for 3X vs. 7-3X and 7X steers (P ≤ 0.05; 0.44, 0.37, and 0.33 ± 0.026 mg/mL, respectively). Also, 3X steers had less mean serum IBR titers (P ≤ 0.05; 0.29 vs. 0.88 and 0.79 ± 0.179 log2, respectively) and less seroconversion to PI-3 virus on d 15 than 7-3X and 7X steers (P ≤ 0.05; 36.0 vs. 76.6 and 57.8 ± 8.24%, respectively). In summary, a gradual reduction in frequency of energy supplementation during a 42-d preconditioning period did not negatively impact growth, but alleviated indices of inflammation and prevented reductions in vaccine response against BVDV-1a and PI-3 viruses compared to steers offered concentrate 3 times weekly during the entire study.