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Introduction: A healthy gastrointestinal (GI) microbiome has been shown to be essential for proper nutrient absorption and metabolism, maintenance of intestinal epithelial integrity and osmolarity, gut immunomodulation, and overall health. One of the most effective ways to promote a healthy GI microbiome is through dietary interventions, such as the addition of prebiotics. Prebiotics are substrates that are selectively utilized by the host GI microbiome through fermentation to confer a health benefit. However, research on prebiotics in companion animals is limited, especially in growing animals. Thus, this study was conducted to assess the effects of a novel prebiotic fiber blend on key parameters related to intestinal health and growth in puppies., Methods: Twenty-two puppies at least 4 months of age but not older than 10 months were fed a commercially available dry food during a prefeed period, and then fed a similarly formulated test food with the addition of the prebiotic fiber blend for a minimum of 90 days. Serum and fecal samples were collected at the end of the prefeed period and throughout the test period., Results: Puppies fed the test food grew as expected for puppies of this age. Complete blood count and serum chemistry analyses were clinically normal for all animals. Fecal score increased linearly, fecal moisture decreased linearly, and pH exhibited a cubic trend throughout the study duration. There was a linear increase in short-chain fatty acids throughout the study, which is associated with favorable digestive and overall health. The inflammatory cytokine interleukin-7 decreased linearly and interleukin-18 trended towards linear decrease., Conclusion: This study showed that puppies continued to grow and develop normally, and experienced serum and stool characteristics indicative of improved GI health when fed a growth food fortified with a novel prebiotic fiber blend. Furthermore, these results contribute to the overall understanding of the effects of prebiotics on the GI health of growing companion animals., Competing Interests: AM, LM, and LH are employees of Hill’s Pet Nutrition, Inc. JB is a subcontractor of Hill’s Pet Nutrition, Inc., (Copyright © 2024 McGrath, Motsinger, Brejda and Hancock.)

Alfalfa is a commonly grown forage in the Intermountain West region of the United States and is often included in the diet of dairy cattle. Alfalfa provides a variety of different nutrients, but the nutrient content of alfalfa varies depending on factors such as the soil, region, cutting, and climate. However, alfalfa leaves tend to have less variation in their nutrient content than alfalfa stems. Fractionating alfalfa may be one way to improve control of nutrients provided when developing a ration for developing dairy heifers. The purpose of this study was to determine whether including fractionated alfalfa in the diet impacts the growth or conception rates of developing dairy heifers. Heifers were allocated to one of three treatments: a control group fed a typical diet ( CON ; n  = 8), a diet that replaced alfalfa with fractionated alfalfa leaf pellets and alfalfa stems (ProLEAF MAX + ProFiber Plus; PLM  +  PFP ; n  = 8), or a diet that replaced alfalfa with alfalfa stems ( PFP ; n  = 8) for 85 d. Heifers were fed individually twice daily and weight, hip height ( HH ), and wither height ( WH ) were recorded every 14 d. Additionally, blood was collected every 28 d, and conception rates were recorded at the end of the trial. Heifers receiving the PFP diet consumed less dry matter ( P  = 0.001) than the CON treatment. Analyses were then conducted to determine nutrient intake and heifers receiving the PFP diet also consumed less neutral detergent fiber ( P  = 0.02), acid detergent fiber ( P  = 0.02), crude protein ( P  = 0.001), and net energy for maintenance ( P  = 0.001) than heifers consuming the CON diet; however, no differences ( P  > 0.10) were observed between heifers fed the CON and PLM + PFP diets. Analysis of body weight gain over the feeding period showed no difference ( P  = 0.52) among heifers consuming the different treatment diets. Additionally, treatment did not affect average daily gain ( P  = 0.49), gain:feed ( P  = 0.82), HH gain ( P  = 0.20), or WH gain ( P  = 0.44) among heifers receiving different diets. Treatment × time altered ( P  < 0.001) blood urea nitrogen when analyzed as a repeated measure. Total feed cost was lowest ( P  < 0.001) for the PFP diet and cost of gain tended ( P  = 0.09) to be increased for the PLM + PFP diet compared to the CON diet. Overall, these data indicate that including alfalfa stems in a developing heifer diet may decrease dry matter intake, lower input costs, and increase profitability, without negatively impacting growth., Competing Interests: The authors each declare there are no conflicts of interest associated with the data presented in this manuscript., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Objective: To examine the effects of age, sex, breed, liver histopathology, and year of death/sample collection on liver copper concentrations in dogs fed various commercial dog foods throughout their lives., Sample: During necropsy, 336 samples were collected between the years 2006 and 2022 from dogs that were fed a variety of commercial dog foods on the market. This study utilized all liver samples available and did not require specific criteria for sample selection., Methods: Liver samples (n = 336) were analyzed as dry weight for copper concentration by inductively coupled plasma-optical emission spectrometry. The potential effects of animal age and year of death/collection (scatterplots and linear regression), sex, liver histopathology (t test), and breed (ANOVA) on liver copper concentration were assessed., Results: Labrador Retrievers had lower liver copper concentrations than Beagles, but mixed breeds did not differ from Beagles or Labrador Retrievers. Analysis of year of death showed that liver copper concentrations decreased from 2006 through 2011, increased in 2012, decreased in 2013, and peaked in 2016, decreasing thereafter. Mean copper concentration of abnormal liver histopathology samples was lower than mean copper concentrations of normal liver histopathology samples. Age (12.9 ± 2.6 years) and sex had no effect on liver copper concentrations. Of note, some samples showed abnormal hepatic pathology., Clinical Relevance: Liver copper concentrations varied significantly with breed and year of death; however, average liver copper concentrations of each year were within normal. However, this was a retrospective population study and diet histories of the dogs were unknown, requiring further investigation.

Alpha-tocopherol (vitamin E) is an antioxidant that is largely involved in immune defense and enhancing the ability of biological systems to respond to oxidative stress. During the process of free radical scavenging, vitamin C supports the regeneration of vitamin E. Although the functions of antioxidants and their importance have been widely studied, the intricate interplay between antioxidants has yet to be fully elucidated, especially in dogs and cats. As such, the objective of the present study was to determine the effect of a combination of dietary antioxidants on DNA damage and antioxidant status in dogs and cats. Forty adult mixed-breed dogs and 40 adult domestic shorthair cats were randomly assigned to one of four treatment groups per species. Dogs and cats remained in these groups for the 84-d duration of the study. The food differed in antioxidant supplementation with the control food meeting all of the Association of American Feed Control Officials requirements for complete and balanced nutrition, including sufficient vitamin E to exceed the published minimum. The treatment diets were targeted to include either 500, 1,000, or 1,500 IU vitamin E/kg as well as 100 ppm of vitamin C and 1.5 ppm of β-carotene in the food. The effect of vitamin E supplementation level on serum vitamin E concentration, DNA damage, and total antioxidant power was evaluated. Feeding diets enriched with antioxidants resulted in an increased (P < 0.05) circulating vitamin E concentration, increased (P < 0.05) immune cell protection, reduced (P < 0.05) DNA damage in dogs, and an improved (P < 0.05) antioxidant status. Overall, these data demonstrated that feeding a dry kibble with an antioxidant blend inclusive of vitamin E, vitamin C, and β-carotene enhanced cell protection and improved antioxidant status in dogs and cats., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Recent research has suggested that different cattle breed types may respond differently to anabolic implant protocols of varying intensity. Therefore, the purpose of this research was to compare anabolic implant protocols in feedlot steers of 2 different breed types. Sixty steers were stratified by weight and breed in a 2 × 3 factorial design examining 2 different breeds: Angus (AN; n=38) or Santa Gertrudis influenced (SG; n=22), and 3 implant strategies: no implant (CON; n=20), a moderate intensity implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MI; n=20), or a high intensity implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; HI; n=20). Steers were randomly placed into pens equipped with GrowSafe bunks to collect dry matter intake and feeding behavior. All animals were fed the same diet. Weight, chute score, exit velocity, serum, rectal temperature, hip height and 12th rib fat thickness were collected approximately every 28 d over a 196 d period. Serum urea nitrogen (SUN) was evaluated as well. Total average daily gain was increased (P < 0.0001) in both the HI and MI steers compared to the CON steers by 29.4% and 26%, respectively. A treatment × breed interaction was observed (P < 0.0001) for hip height, with AN-CON steers being shorter (P < 0.0007) than AN-HI, SG-CON, SG-MI, and SG-HI steers. A breed × treatment interaction was observed (P < 0.004) for chute score and rectal temperature, with SG-HI and SG-MI steers having increased chute scores (P < 0.001) when compared to AN-HI, AN-MI, AN-CON, and SG-CON throughout the course of the trial. Additionally, SG-HI and SG-MI steers had an increased rectal temperature (P < 0.004) compared to AN-HI, AN-MI, AN-CON, and SG-CON steers. A breed effect was observed (P = 0.002) for SUN with AN steers having increased (P = 0.002) SUN concentration compared to SG sired steers, in addition to a treatment effect (P < 0.0001), with CON steers having a higher (P < 0.0001) SUN concentration than MI and HI steers, regardless of breed. The MI implant protocol increased net return per head, on average, by $97.28, regardless of breed, while the HI implant protocol increased net return by only $80.84. Taken together, despite the cattle breed types responding differently to the different anabolic implant protocols at times, a moderate intensity anabolic implant protocol was optimal in this experiment for steers raised in a temperate climate., Competing Interests: Declaration of Interest None., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Research suggests that androgens increase skeletal muscle growth by modulating polyamine biosynthesis. As such, the objective of this study was to investigate effects of anabolic hormones, polyamine precursors, and polyamines relative to proliferation, protein synthesis, and the abundance of mRNA involved in polyamine biosynthesis, proliferation, and protein synthesis in C2C12 and Sol8 cells. Cultures were treated with anabolic hormones (trenbolone acetate and/or estradiol), polyamine precursors (methionine or ornithine), or polyamines (putrescine, spermidine, or spermine). Messenger RNA was isolated 0.5 or 1, 12, or 24 h post-treatment. The cell type had no effect ( p > 0.10) on proliferation, protein synthesis, or mRNA abundance at any time point. Each treatment increased ( p < 0.01) proliferation, and anabolic hormones increased ( p = 0.04) protein synthesis. Polyamines increased ( p < 0.05) the abundance of mRNA involved in polyamine biosynthesis, proliferation, and protein synthesis. Treatment with polyamine precursors decreased ( p < 0.05) the abundance of mRNA involved in proliferation and protein synthesis. Overall, C2C12 and Sol8 myoblasts do not differ ( p > 0.10) in proliferation, protein synthesis, or mRNA abundance at the time points assessed. Furthermore, anabolic hormones, polyamines, and polyamine precursors increase proliferation and protein synthesis, and polyamines and their precursors alter the abundance of mRNA involved in growth.

The majority of beef cattle in the United States often receive at least one anabolic implant resulting in improved growth, feed efficiency, and environmental and economic sustainability. However, the physiological and molecular mechanisms through which anabolic implants increase skeletal muscle growth of beef cattle remain elusive. The objective of this study was to identify transcriptional changes occurring in skeletal muscle of steers receiving anabolic implants containing different steroid hormones. Forty-eight steers were stratified by weight into 1 of 4 (n = 12/treatment) implant treatment groups: (1) estradiol (ImpE2; 25.7 mg E2; Compudose, Elanco Animal Health, Greenfield, IN), (2) trenbolone acetate (ImpTBA; 200 mg TBA; Finaplix-H, Merck Animal Health, Madison, NJ), (3) combination (ImpETBA; 120 mg TBA + 24 mg E2; Revalor-S, Merck Animal Health), or (4) no implant (CON). Skeletal muscle biopsies were taken from the longissimus 2 and 10 d post-implantation. The mRNA abundance of 94 genes associated with skeletal muscle growth was examined. At 10 d post-implantation, steers receiving ImpETBA had greater (P = 0.02) myoblast differentiation factor 1 transcript abundance than CON. Citrate synthase abundance was increased (P = 0.04) in ImpETBA steers compared to CON steers. In ImpE2 steers 10 d post-implantation, muscle RING finger protein 1 decreased (P = 0.05) compared to CON steers, and forkhead box protein O4 decreased (P = 0.05) in ImpETBA steers compared to CON steers. Interleukin-6 abundance tended to be increased (P = 0.09) in ImpE2 steers compared to both ImpETBA and CON steers. Furthermore, interleukin-10 mRNA abundance tended to be increased (P = 0.06) in ImpTBA steers compared to ImpETBA steers. Leptin receptor abundance was reduced (P = 0.01) in both ImpE2 and ImpTBA steers when compared to CON steers. Abundance of phosphodiesterase 4B was increased (P = 0.04) in ImpTBA steers compared to CON steers 2 d post-implantation. Taken together, the results of this research demonstrate that estradiol increases skeletal muscle growth via pathways related to nutrient partitioning and mitochondria function, while trenbolone acetate improves steer skeletal muscle growth via pathways related to muscle growth., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Two methods that the beef cattle industry can use to improve efficiency, sustainability, and economic viability are growth promotants and crossbreeding cattle of different breed types. In the United States, over 90% of cattle receive an anabolic implant at some point during production resulting in an overall increase in skeletal muscle growth. Recent research suggests that the two main cattle breed types, Bos indicus and Bos taurus, respond differently to anabolic implants. The objective of this study was to characterize changes that occur in skeletal muscle following implanting in Bos indicus influenced steers or Bos taurus steers. Twenty steers were stratified by initial weight in a 2 × 2 factorial design examining two different breeds: Angus (AN; n = 10) or Santa Gertrudis influenced (SG; n = 10), and two implant strategies: no implant (CON; n = 10) or a combined implant containing 120 mg TBA and 24 mg E2 (IMP; n = 10; Revalor-S, Merck Animal Health). Skeletal muscle biopsies were taken from the longissimus thoracis (LT) 2 and 10 d post-implantation. The mRNA abundance of 24 genes associated with skeletal muscle growth were examined, as well as the protein expression of µ-calpain and calpastatin. Succinate dehydrogenase mRNA abundance was impacted (P = 0.05) by a breed × treatment interaction 2 d post-implanting, with SG-CON having a greater increased abundance than all other steers. A tendency for a breed × treatment interaction was observed for calpain-6 mRNA (P = 0.07), with SG-CON having greater abundance than AN-CON and SG-IMP. Additionally, calpastatin protein expression was altered (P = 0.01) by a breed × treatment interaction, with SG-CON and SG-IMP steers having increased expression (P = 0.01) compared with AN-CON steers. At 2 d post-implanting, a breed × treatment interaction was observed with SG-CON steers having greater (P = 0.05) mRNA abundance of mitogen-activated protein kinase compared with AN-CON steers. Furthermore, breed affected (P = 0.05) calpastatin abundance with AN steers having increased (P = 0.05) abundance 2 d post-implanting compared with SG steers. Meanwhile, implants tended to affect (P = 0.09) muscle RING finger protein-1 mRNA abundance, with CON steers having increased (P = 0.09) abundance compared with that of IMP steers. These findings suggest that cattle breed type and anabolic implants impact calpastatin expression and mRNA abundance associated with protein turnover in the LT of feedlot steers 2 and 10 d post-implantation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introducing Bos indicus (BI) genetics into a beef herd has the potential to increase environmental sustainability. When introducing BI genetics, there are concerns regarding negative impacts on temperament, growth, and carcass characteristics. Implants are routinely used in the United States, with majority of cattle on feed receiving an anabolic implant to improve growth and efficiency, however research regarding the interaction between cattle breed type and anabolic implants is limited. This research compared the use of implants in BI influenced animals versus Bos taurus in a feedlot setting. Twenty steers were stratified by initial weight in a 2 × 2 factorial design examining two different breeds: Angus (AN; n = 10) or Santa Gertrudis influenced (SG; n = 10), and two implant strategies: no implant (CON; n = 10) or a combined implant containing 120 mg TBA and 24 mg E2 (IMP; n = 10; Revalor-S, Merck Animal Health). We hypothesized that anabolic implants would improve growth and feedlot performance of BI influenced animals. Steers were randomly placed into covered pens equipped with GrowSafe bunks and fed the same ration for 129 d. Steers were weighed every 28 d. Dry matter intake, feeding behavior, and carcass data of the steers was collected. Blood was collected and harvested as serum on d 0, 2, 10, 28 and every 28 d after that, and analyzed for serum urea nitrogen (SUN), haptoglobin, and 25HydroxyVitamin D. Angus steers tended to gain more (P = 0.06) weight than SG, while IMP tended to gain more (P = 0.10) weight than CON with no breed × treatment interaction observed (P > 0.10). A breed × treatment interaction was observed when analyzing SUN (P = 0.05) and haptoglobin (P = 0.02) concentrations. Serum 25HydroxyVitmain D concentrations tended to be increased (P = 0.09) in SG-IMP steers compared to SG-CON steers. Angus steers tended (P = 0.10) to have greater amounts of marbling compared to SG steers, while SG steers had improved (P = 0.04) yield grade. Economic return was decreased by $46 a head when introducing SG genetics, while implanting steers improved economic return by $46 a head. This research provides evidence suggesting that BI influenced animals may respond differently to anabolic implants when compared to BT animals. Economic analyses demonstrate that anabolic implants improve economic return to beef producers, while introducing SG genetics decreases economic return in animals raised in more temperate climates., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Fifty Angus-sired steers were utilized to evaluate the effects of anabolic implants varying in hormone type and concentration on performance, carcass traits, and plasma and liver trace mineral concentrations over 129 d. Steers were stratified by weight into one of four ( n = 12 or 13/treatment) implant treatments: (1) estradiol (E2; 25.7 mg E2; Compudose, Elanco Animal Health, Greenfield, IN, USA), (2) trenbolone acetate (TBA; 200 mg TBA; Finaplix-H, Merck Animal Health, Madison, NJ, USA), (3) combination implant (ETBA; 120 mg TBA + 24 mg E2; Revalor-S, Merck Animal Health), or (4) no implant (CON). Steers were randomly assigned to pens equipped with GrowSafe bunks and fed a corn and barley-based finishing ration. Overall average daily gain and body weight were greater for ETBA and TBA than CON ( p ≤ 0.04), but not E2 ( p ≥ 0.12). Feed efficiency and hot carcass weight were only greater than CON for ETBA ( p ≤ 0.03). Plasma and d 2 liver Zn concentrations were lesser for ETBA than CON ( p ≤ 0.01) and d 10 liver Mn was lesser ( p = 0.0003) for TBA than CON. These data indicate that implants containing TBA influence growth and trace mineral parameters, though more work investigating this relationship is necessary.

Alfalfa is often included in the diets of beef animals; however, the nutrient content of alfalfa is variable depending on the region in which it is grown, climate, soil, and many other factors. The leaf portion of alfalfa has a less variable nutrient composition than the stem portion of the plant. The variability that is present in the alfalfa plant can make the development of total mixed rations of consistent nutrient content difficult. As such, the purpose of this study was to determine how the inclusion of fractionated alfalfa leaves and alfalfa stems impacts performance and carcass quality of finishing beef steers. Twenty-four steers were allocated to one of three treatments: a control group fed a typical finishing diet with alfalfa as the forage (CON; n = 8), a typical diet that replaced alfalfa with fractionated alfalfa leaf pellets and alfalfa stems (ProLEAF MAX™ + ProFiber Plus™; PLM+PFP; n = 8), or a typical diet that replaced alfalfa with alfalfa stems (PFP; n = 8) for 63 days. Steers were fed individually once daily, weighed every 14 days and ultrasound images were collected every 28 days. At the end of the feeding trial, steers were harvested at a commercial facility and carcass data was obtained. Analysis of dry matter intake demonstrated that steers receiving the PFP and CON diets consumed more feed ( P < 0.001) than steers consuming the PLM+PFP diet. Steers receiving the PLM+PFP diet gained less ( P < 0.001) weight than the steers receiving the other two dietary treatments. No differences ( P > 0.10) in feed efficiency or carcass characteristics were observed. Steers receiving the PFP diet had improved ( P = 0.016) cost of gain ($0.93 per kg) when compared with steers receiving PLM+PFP ($1.08 per kg) diet. Overall, our findings demonstrate that the inclusion of PFP in place of alfalfa hay in a finishing diet has the potential to improve cost of gain, without negatively affecting growth, performance, or carcass characteristics of finishing feedlot steers., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Emerging research suggests that hormones found in anabolic implants interact with polyamine biosynthesis. The objective of this study was to determine the effects of steroidal hormones, polyamines and polyamine precursors on bovine satellite cell (BSC) differentiation and polyamine biosynthesis temporally. Primary BSCs were induced to differentiate in 3% horse serum (CON) and treated with 10 nM trenbolone acetate (TBA), 10 nM estradiol (E2), 10 nM TBA and 10 nM E2, 10 mM methionine, 8 mM ornithine, 2 mM putrescine, 1.5 mM spermidine, or 0.5 mM spermine. Total mRNA was isolated 0, 2, 4, 8, 12, 24, and 48 h post-treatment. Abundance of mRNA for genes associated with induction of BSC differentiation: paired box transcription factor 7, myogenic factor 5, and myogenic differentiation factor 1 and genes in the polyamine biosynthesis pathway: ornithine decarboxylase and S-adenosylmethionine-were analyzed. Overall, steroidal hormones did not impact ( p > 0.05) mRNA abundance of genes involved in BSC differentiation, but did alter ( p = 0.04) abundance of genes involved in polyamine biosynthesis. Polyamine precursors influenced ( p < 0.05) mRNA of genes involved in BSC differentiation. These results indicate that polyamine precursors and polyamines impact BSC differentiation and abundance of mRNA involved in polyamine biosynthesis, while steroidal hormones altered the mRNA involved in polyamine biosynthesis.