Effects of extended-release eprinomectin on fescue toxicosis, performance, and reproduction on fall-calving beef cows

Abstract The objective of this experiment was to evaluate effects of extended-release eprinomectin on fescue toxicosis and impacts on performance and reproduction in fall-calving beef cows. Fall-calving Angus × Simmental multiparous cows [n = 335; age = 5.8 ± 2.1 yr; 586.5 ± 6.0 kg body weight (BW); 5.48 ± 0.05 body condition score (BCS)] were stratified by BW, age, and BCS and randomly assigned to one of three treatments. Treatments included a spring injection of extended-release eprinomectin (SERE) on day 0, a fall injection of extended-release eprinomectin injection (FERE) on day 84, and a saline control (CON). All treatments were administered at a rate of 1 mL/50 kg BW. Prior to the experiment, all cows were treated with oral fenbendazole to minimize parasite load. Cows grazed endophyte-infected tall fescue. Hair coat score (HCS), BW, and BCS were recorded on all cattle. Fecal egg count (FEC), respiration rate (RR), horn fly and tick count, hematocrit (% packed cell volume, PCV), and serum prolactin were analyzed on a subset of cows (35/treatment). On day 194, cows were artificially inseminated (AI) and 11 d following AI were exposed to bulls for 51 d. Milk production was estimated on day 210 on a subset of 85 cow–calf pairs (28–29/treatment). There was a tendency for a treatment × time interaction (P = 0.07) for FEC likely driven by an increase in FEC of the CON cattle at day 126 compared to SERE and FERE. There was a tendency for a treatment × time interaction (P = 0.06) for cow BW, largely driven by time differences; however, there was no effect of treatment (P = 0.84) on BW. There was no difference (P ≥ 0.13) in cow PCV, fly and tick count, BCS, HCS, RR, and serum prolactin throughout the experiment. Additionally, there was no difference (P ≥ 0.46) in Julian calving date, calf birth BW, or milk production between treatments. Interestingly, heifer calves born to FERE dams tended to have greater (P = 0.06) weaning BW compared to heifer calves born to CON dams. In addition, there was no difference (P ≥ 0.17) in heat patch scores, AI conception rates, or overall pregnancy rates between treatments. Extended-release eprinomectin did not impact cow growth performance, reproductive performance or fescue toxicity symptoms when grazing endophyte-infected tall fescue; however, calf weaning BW tended to be improved.

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Effects of spring administration of extended-release eprinomectin on fescue toxicosis, performance, and reproduction of fall-born beef heifers

Translational Animal Science ◽

10.1093/tas/txz015 ◽

2019 ◽

Vol 3 (1) ◽

pp. 20-28 ◽

Cited By ~ 1

Author(s):

Mareah J Volk ◽

Jessica M Kordas ◽

Rebecca S Stokes ◽

Frank A Ireland ◽

Daniel W Shike

Keyword(s):

Extended Release ◽

Treatment Time ◽

Average Daily Gain ◽

Parasite Load ◽

Underlying Mechanism ◽

Pregnancy Rates ◽

Serum Prolactin ◽

Fescue Toxicosis ◽

Beef Heifers ◽

Time Interaction

Abstract The objective of this experiment was to assess the effects of eprinomectin, an extended-release injectable parasiticide, on fescue toxicosis and its impacts on beef heifer performance and reproduction. Fall-born Angus × Simmental heifers (age = 246.3 ± 22.4 d; 264.8 ± 21.1 kg body weight [BW]) were randomly assigned to one of two treatments: extended-release eprinomectin injection (ERE; n = 100) or control (CON; saline; n = 99). Treatments were administered at a rate of 1 mL/50 kg BW. Prior to experiment, heifers were dosed with oral fenbendazole to minimize parasite load. All heifers grazed endophyte-infected tall fescue as a single group and were offered a 50:50 supplement mix of corn gluten feed and soybean hulls (2.7 kg as fed per heifer per day). Body condition scores (BCS), BW, hair coat score (HCS), blood, and fecal samples were collected throughout the experiment. A subset of 40 heifers were randomly selected (20 per treatment) to assess respiration rate (RR). On d 138, heifers began a 14-d controlled internal drug release + prostaglandin synchronization protocol. Following artificial insemination (AI), heifers were exposed to five bulls for 71 d. On d 214 and 291, AI and overall pregnancy rates, respectively, were determined. There was a treatment × time interaction (P < 0.01) for BW, BCS, and average daily gain (ADG). The ERE heifers had greater (P < 0.04) BW and BCS compared to CON heifers from d 55 and 112, respectively. In addition, ERE heifers had greater (P ≤ 0.04) ADG from d 0 to 56, 56 to 112, 112 to 171, and 171 to 214; however CON heifers had greater (P < 0.01) ADG from d 214 to 291. There was no treatment × time interaction or treatment difference (P ≥ 0.27) for HCS, RR, and serum prolactin concentrations. However, serum prolactin decreased (P < 0.01) in all heifers over time. There was a treatment × time interaction (P<0.01) for fecal egg counts (FEC). The FEC did not differ (P ≥ 0.32) on d −1 or 55; however, ERE heifers had decreased (P < 0.01) FEC compared with CON heifers on d 111 (1.52 vs. 13.56 eggs per gram). The ERE heifers tended (P = 0.10) to have greater AI pregnancy rates (69% vs. 58%) and had greater (P = 0.01) overall pregnancy rates (84% vs. 68%) than CON heifers. Spring administration of extended-release eprinomectin improved BW, ADG, BCS, and AI and overall pregnancy rates in fall-born beef heifers. However, the underlying mechanism is still unclear, as there were minimal to no differences in HCS, RR, serum prolactin, and FEC.

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80 Evaluation of extended release eprinomectin efficacy on multiparous beef cow performance

Journal of Animal Science ◽

10.1093/jas/skz397.024 ◽

2020 ◽

Vol 98 (Supplement_2) ◽

pp. 11-11

Author(s):

Laine Zammit ◽

Jermey G Powell ◽

Reagan N Cauble ◽

Toby D Lester ◽

Callan Lichtenwalter ◽

...

Keyword(s):

Extended Release ◽

Reproductive Traits ◽

Economic Loss ◽

Beef Cows ◽

Negative Control ◽

Beef Cow ◽

Body Weights ◽

Calving Season ◽

Cow Performance ◽

Fall Calving

Abstract Internal parasitism inevitability prompts economic loss in beef cattle production by decreasing growth performance and reproductive traits. Previous studies have conflicting results on the macrocyclic lactones (ML) efficacy against internal parasitism. The objective of this study was to evaluate the efficacy of milbeymycin and avermectin sub groups of ML on cow performance. Multiparous fall calving, crossbred beef cows (n = 106) were allocated randomly to 1 of 3 anthelmintic treatments: 1) Negative control (CON), in which cows did not receive an anthelmintic, 2) Injectable moxidectin (MOX) and 3) Injectable extended release eprinomectin (ERE). Body weights (BW), body condition scores (BCS), and fecal egg counts (FEC) were taken throughout the duration of the calving season to weaning on d0, d80, d162, and d217, with weaning occurring on d217. Performance data were analyzed using the MIXED procedures of SAS, and pregnancy data were analyzed using the GENMOD procedures of SAS. Significance was fixed at P < 0.05 and tendencies were established from 0.05 ≤ P ≤ 0.10. There was no effect of anthelmintic treatment on cow BW (P ≥ 0.57) or cow BCS (P ≥ 0.22) during the 217 d study; however, CON cows tended to have lower BCS (P = 0.08) throughout the duration of the study. Cows treated with ERE had fewer FEC compared to MOX and CON groups (P ≤ 0.001) and tended to improve pregnancy rates (c2 = 0.0546). Calf weaning weight was similar among treatments averaging 216, 225, and 223 kg regarding CON, MOX, and ERE cow treatments, respectively.

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Identification of Breed Differences in Known and New Fescue Toxicosis Associated Phenotypes in Charolais-and Hereford-Sired Crossbred Beef Cows

Animals ◽

10.3390/ani11102830 ◽

2021 ◽

Vol 11 (10) ◽

pp. 2830

Author(s):

Kayla M. Lucas ◽

Dawn A. Koltes ◽

Laura R. Meyer ◽

John D. Tucker ◽

Donald S. Hubbell ◽

...

Keyword(s):

Heat Stress ◽

Average Daily Gain ◽

Beef Cows ◽

Fescue Toxicosis ◽

Phosphorus Concentration ◽

Study Objective ◽

Toxin Exposure ◽

Fall Calving ◽

Vaginal Temperature ◽

Daily Gain

Beef cattle phenotypes are affected by the consumption of toxic fescue. Toxic fescue’s impact is dependent on heat stress and breed composition, with genetic variability for robustness to toxin exposure believed to exist within and across breeds. The study objective was to characterize the effect of fescue toxicosis across breeds for known and novel heat and fescue stress-associated phenotypes. One-hundred crossbred fall-calving Charolais- and Hereford-sired cows of parities 1–3 were allocated to graze either toxic fescue (n = 50), non-toxic fescue (n = 25), or a rotation between toxic and non-toxic fescue (n = 25) for 156 days. Phenotypes impacted by breed (genetics) included hair coat score (p < 0.0001), hair reduction/shedding rate (p < 0.05), rectal temperature (RT) (p < 0.0001), vaginal temperature (p < 0.05), serum phosphorus concentration (p < 0.02) and respiration rate (RR) (p < 0.003). Cows on toxic fescue experienced reduced hair shedding efficacy (p < 0.0001), higher vaginal temperatures (p < 0.0001), increased systolic blood pressure (p < 0.04), increased RR (p < 0.0001) and reduced average daily gain (p < 0.0001), compared to cows grazing non-toxic fescue. Calves born from cows with higher RT during the last third of gestation had higher RT at weaning (p < 0.02), indicating potential physiological effects of in utero heat stress. The study indicates that beef cows exhibit variable responses to toxic fescue within and across breeds which may impact future calf phenotypes.

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Ruminal motility, reticuloruminal fill, and eating patterns in steers exposed to ergovaline

Journal of Animal Science ◽

10.1093/jas/skz374 ◽

2019 ◽

Vol 98 (1) ◽

Cited By ~ 2

Author(s):

Gyuchul Ahn ◽

Kara Ricconi ◽

Suelen Avila ◽

James L Klotz ◽

David L Harmon

Keyword(s):

Tall Fescue ◽

Rumen Content ◽

Serum Prolactin ◽

Fescue Toxicosis ◽

Eating Patterns ◽

Complete Understanding ◽

Wireless System ◽

Eating Pattern ◽

Underlying Mechanisms ◽

Pressure Changes

Abstract Fescue toxicosis is problematic for growing steers, causing lower DMI and productivity when fed endophyte-infected (E+) tall fescue. A complete understanding of underlying mechanisms of how fescue toxicosis affects growing steers is lacking. Therefore, the overall objective of this multiexperiment study was to determine whether ruminally dosed ergovaline (ERV) affects rumen motility, rumen contents, and eating patterns. In Exp. 1, an 8-h period to assess ruminal motility began 4 h after feeding by monitoring pressure changes using a wireless system for 21 d. Eight ruminally cannulated steers (283 kg BW) were pair fed with alfalfa cubes (1.5 × NEm) and assigned to endophyte free (E−; 0 μg ERV/kg BW/d) or E+ treatment (20 μg ERV/kg BW/d). Overall, E+ steers had more frequent rumen contractions (Seed P = 0.05 and day of feeding P = 0.02). On days 7 to 9, both treatments showed lower frequencies and E− steers had greater amplitude of contractions (P < 0.001) that corresponded with decreased DMI. In Exp. 2, steers remained in pairs assigned in Exp. 1 (322 kg BW), but reversed seed treatments while increasing ERV levels (titrated 0, 5, 10, 15, and 20 μg ERV/kg BW/d over 57 d). There were no differences between E− and E+ for frequency (P = 0.137) or amplitude of contractions (P = 0.951), but increasing ERV dosage, decreased frequency (P = 0.018) and amplitude (P = 0.005), coinciding with lower DMI. In Exp. 3, 8 steers (589 kg) were pair fed and ruminally dosed 15 μg ERV/kg BW/d, and rumen motility data were collected for 21 d. E− steers showed higher amplitude and lower frequency of contractions than E+ steers with seed (P < 0.001), day (P < 0.001), and seed × day (P < 0.04) effects, but rumen fill was not different between E− and E+ (P > 0.29). Serum prolactin concentrations were lower in E+ steers in Exp. 1 to 3. Eating patterns of pair-fed E− and E+ steers were relatively slower in E+ than E− (Exp. 4) by measuring every 2 h across 24 h. Number of meals were higher in E+ than E− steers, but meal duration and meal size were not different between treatments. Rumen content (DM%) tended to be higher in E+ than in E− when steers were fed once a day (P = 0.07), but there was no difference for rumen content (DM%) when E− and E+ steers were fed 12 times a day (P = 0.13). These results suggest the changes in rumen fill associated with fescue toxicosis may be driven more by changes in feeding behavior and eating pattern rather than by changes in motility.

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Tall Fescue Toxicosis Mitigation Strategies: Comparisons of Cow-Calf Returns in Spring- and Fall-Calving Herds

Journal of Agricultural and Applied Economics ◽

10.1017/s1074070800024123 ◽

2012 ◽

Vol 44 (4) ◽

pp. 577-592 ◽

Cited By ~ 9

Author(s):

Stephen A. Smith ◽

James D. Caldwell ◽

Michael P. Popp ◽

Kenneth P. Coffey ◽

John A. Jennings ◽

...

Keyword(s):

Tall Fescue ◽

Mitigation Strategies ◽

Fescue Toxicosis ◽

South Central ◽

Central United States ◽

Calving Rate ◽

Cow Calf ◽

Calving Season ◽

Fall Calving ◽

Tall Fescue Toxicosis

Tall fescue toxicosis adversely affects calving rate and weight gains reducing returns to cow-calf producers in the south–central United States. This grazing study estimated animal and economic performance implications of endophyte-infected fescue and calving season. Establishing novel endophyte-infected tall fescue on 25% of pasture acres resulted in improved calving rates (87% vs. 70%), weaning weights (532 lbs vs. 513 lbs), and partial returns per acre ($257 vs. $217). Additionally, fall-calving cows had higher calving rates (91% vs. 67%), weaning weights (550 lbs vs. 496 lbs), and partial returns per acre ($269 vs. $199) than spring calving cows.

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Changes in Cytochrome P450 in Katahdin Ewes Fed Endophyte-infected Tall Fescue Seed Diets in Spring and Fall

Journal of Animal Science ◽

10.1093/jas/skab096.074 ◽

2021 ◽

Vol 99 (Supplement_2) ◽

pp. 40-41

Author(s):

Mohan Acharya ◽

Joan M Burke ◽

Erin Wood ◽

Yan Huang ◽

Palika Dias Morse ◽

...

Keyword(s):

Cytochrome P450 ◽

Serum Concentration ◽

Rectal Temperature ◽

Tall Fescue ◽

Repeated Measures ◽

Ergot Alkaloids ◽

Serum Prolactin ◽

Fescue Toxicosis ◽

Pregnancy Status ◽

Soy Hulls

Abstract Objective was to examine the activity of cytochrome P450 (CYP), a liver enzyme that metabolizes ergot alkaloids which is hindered by this fescue toxin, as an indicator of fescue toxicosis in sheep. In spring and fall, ewes were blocked by age and BW, and randomly assigned to 1 kg/ewe/d of endophyte-infected (E+; 61% of diet in fall, 13% of diet in spring; 0.8 µg/g of ergovaline; and soy hulls, alfalfa pellets, cottonseed hulls, molasses) or non-infected (E-; same proportion of E+/season and same feeds) tall fescue seed supplement (n = 10/diet in each season) for 28 d, plus hay, mineral and water. Ewes were exposed to teaser, d -21 to 0, and intact rams, d 0 (first day of diet) to 30. Rectal temperature (RT), serum concentration of prolactin (using RIA), and CYP were determined every 7–14 d between d 0–28, and pregnancy status on d 56. PromegaTM P450-Glo assay was used to determine CYP from serum. Data were analyzed by using PROC MIXED with repeated measures (SAS). Rectal temperature of E+ compared with E- ewes was elevated on at least one day in fall and spring (diet × season × d, P < 0.001). Serum prolactin was lower in E+ compared with E- ewes (diet × d, P < 0.001) and lower in fall (P < 0.001). CYP was higher in E- ewes on d 28 in fall (diet × season × d, P = 0.008), but otherwise similar between diets, and higher in fall than spring (P < 0.001). There was an unexpected negative correlation between CYP and prolactin (R = -0.24; P < 0.009), but there appears to be a subpopulation of ewes with low prolactin and lower CYP. CYP activity in sera may not be a marker for fescue toxicosis in ewes.

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225 Effects of late gestation Calcium salts of fatty acids supplementation to beef cows on offspring pre-weaning growth performance and gene expression

Journal of Animal Science ◽

10.1093/jas/skaa054.236 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 136-136

Author(s):

Taoqi Shao ◽

Frank Ireland ◽

Joshua Mccann ◽

Daniel W Shike

Keyword(s):

Gene Expression ◽

Fatty Acids ◽

Docosahexaenoic Acid ◽

Eicosapentaenoic Acid ◽

Growth Performance ◽

Treatment Time ◽

Beef Cows ◽

Late Gestation ◽

Time Interaction ◽

Subcutaneous Adipose

Abstract Objectives were to investigate the effects of supplementing Ca salts of fatty acids to beef cows during late gestation on the pre-weaning growth performance and gene expression of steer progeny. Ninety-six fall-calving, Angus x Simmental cows (BW = 601±76 kg) were randomly assigned into 8 pastures (4 pastures/treatment; 12 cows/pasture), supplemented soyhulls mixed with 80 g/cow/d Strata + 80 g/cow/d Prequel (PUFA, rich in linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid) or 155 g/cow/d EnerGII (SFA/MUFA, rich in palmitic and oleic acids) for 76.5±6.0 d prepartum. Cow/calf pairs were comingled after calving. Biopsies of Longissimus dorsi (LD) and subcutaneous adipose were taken at birth and 3 wk before weaning (186±6 d). The data were analyzed using the MIXED procedure of SAS. Supplementing PUFA increased (P < 0.01) cow plasma eicosapentaenoic acid and docosahexaenoic acid at midpoint of supplementation. At birth, PUFA steers had greater (P < 0.05) plasma EPA and lower (P < 0.01) plasma linolenic acid and oleic acid than SFA/MUFA steers. Weaning BW and pre-weaning ADG of the SFA/MUFA steers tended (P < 0.07) to be greater than PUFA steers. SFA/MUFA steers had increased (P = 0.04) expression of Zfp423 in adipose. There tended to be a treatment×time interaction (P = 0.06) for expression of Myf5 in LD; expression of Myf5 was greatest in SFA/MUFA steers at birth. There was a treatment×time interaction (P = 0.05) for expression of Pax7; expression was greater in SFA/MUFA steers at birth than any treatment at weaning. There were treatment×time interactions (P < 0.01) for expression of Myh7 and C/EBPβ in LD; expressions were greatest in PUFA steers at weaning. Supplementing Ca salts of PUFA to beef cows during late gestation altered plasma fatty acid profile of cow and calf, affected gene expression, and decreased offspring growth performance.

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Clinical manifestations of tall fescue (Festuca arundinacea) and perennial ryegrass (lolium perenne) toxicosis in Oregon and Japan

NZGA: Research and Practice Series ◽

10.33584/rps.13.2006.3170 ◽

2007 ◽

Vol 13 ◽

pp. 369-372

Author(s):

L.L. Blythe ◽

A.M. Craig ◽

C. Estill ◽

C. Cebra

Keyword(s):

Lolium Perenne ◽

Perennial Ryegrass ◽

Tall Fescue ◽

Festuca Arundinacea ◽

Clinical Manifestations ◽

Beef Cows ◽

Fescue Toxicosis ◽

Angus Cattle ◽

Multiple Vehicles ◽

Tall Fescue Toxicosis

There are multiple vehicles for endophyte toxicosis in animals including exposure from pasture, straw residues and seed screenings. This report discusses the clinical cases typically seen with tall fescue and perennial ryegrass toxicosis in Oregon and Japan. Case I involves a herd of 330 Black Angus cattle. Before the March calving season the owner wished to increase the protein content of the feed ration by feeding pellets made of seed screenings and grass hay. Forty two animals were lost to tall fescue toxicosis and dry gangrene of the feet and legs. Case II involves 1300 beef cows in Eastern Oregon fed grass straw; 485 animals were lost due to dry gangrene characteristic of tall fescue toxicosis. Case III describes 4 of 15 cases of both tall fescue and perennial ryegrass toxicosis in Japanese black cattle. Case IV involves llamas and alpacas on pasture and lawn paddocks where some animals were affected by tall fescue and some by perennial ryegrass. Keywords: tall fescue, Festuca arundinacea L., perennial ryegrass, Lolium perenne, endophyte, Neotyphodium coenophialum, Neotyphodium lolii

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155 Evaluation of cytokine response as an indicator of genetic resistance to fescue toxicosis in purebred Angus cattle

Journal of Animal Science ◽

10.1093/jas/skz053.102 ◽

2019 ◽

Vol 97 (Supplement_1) ◽

pp. 45-46

Author(s):

Kyle Mayberry ◽

Rebecca K Poole ◽

McKayla A Newsome ◽

Piush Khanal ◽

Matthew H Poore ◽

...

Keyword(s):

G Protein ◽

Tall Fescue ◽

Repeated Measures ◽

Genetic Resistance ◽

Cytokine Response ◽

Serum Prolactin ◽

Fescue Toxicosis ◽

Animal Performance ◽

Negative Effects ◽

G Protein Coupled

Abstract Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue. However, varying responses among cattle potentially implies genetic tolerance to the syndrome. Therefore, the objective was to evaluate the cytokine response of cows deemed either tolerant or susceptible to endophyte-infected fescue. Angus cows, 2–4 yrs old, grazed endophyte-infected tall fescue at two locations for 13 weeks starting mid-April 2016. A post-hoc analysis of animal performance was utilized to designate cattle into either tolerant (n = 20) or susceptible (n = 20) groups, based on physiological responses (changes in ADG) to chronic exposure to endophyte-infected fescue. Blood samples collected on weeks 1, 7, and 13 were used to evaluate serum prolactin (PRL) concentration. Cytokine concentrations were evaluated via Quantibody Bovine Cytokine Arrays. Data were analyzed using PROC MIXED of SAS with repeated measures. There were no differences by location or week. Tolerant cows tended to have decreased overall PRL concentrations compared to susceptible cows (98.3 and 138.4 ng/mL, respectively; P = 0.08). G protein-coupled receptor associated sorting protein (GASP)-1, a down-regulator of G protein-coupled receptors including D2-dopamine receptor a regulator of PRL secretion, was greater in tolerant cows when compared to susceptible cows (4.7 and 4.2 ng/mL; P = 0.03). Vascular endothelial growth factor (VEGF)-A was greater in tolerant cows when compared to susceptible cows (0.5 and 0.2 ng/mL; P = 0.02). Finally, interleukin (IL)-4, an anti-inflammatory cytokine, tended to be greater in tolerant cows when compared to susceptible cows (2.2 and 0.8 ng/mL, respectively; P = 0.07). Based on these data, greater concentrations of GASP-1, VEGF-A, and IL-4 in tolerant compared to susceptible cattle may mitigate the detrimental effects of fescue toxicosis, including suppressed PRL and vasoconstriction, leading to improved animal performance in a fescue environment. Additionally, these cytokines may serve as potential biomarkers for determining an animal’s tolerance or susceptibility to negative effects associated with endophyte-infected tall fescue

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PSI-18 Effects of supplementing polyunsaturated fatty acids during late gestation on performance of fall-calving cows

Journal of Animal Science ◽

10.1093/jas/skz122.436 ◽

2019 ◽

Vol 97 (Supplement_2) ◽

pp. 247-248

Author(s):

Trenton L Black ◽

Taoqi Shao ◽

Frank A Ireland ◽

Joshua C McCann ◽

Daniel W Shike

Keyword(s):

Fatty Acids ◽

Tall Fescue ◽

Artificial Insemination ◽

Body Condition Score ◽

Beef Cows ◽

Late Gestation ◽

Experimental Unit ◽

Condition Score ◽

Pufa Supplement ◽

Fall Calving

Abstract The objective was to determine the effects of supplementing calcium salts of PUFA or SFA + MUFA during late gestation on performance of fall-calving beef cows through calving. Mature, Simmental x Angus cows confirmed pregnant to a synchronized artificial insemination (AI) and fetal sexed were selected prior to the start of the experiment. At 200 d of gestation, cows (n = 96; BW = 603 ± 72 kg) were stratified by age, AI service sire, fetal sex and BW and allotted to 8 groups. Groups were randomly assigned to 1 of 2 treatments (4 groups per treatment): SFA + MUFA (0.155 kg of EnerGII per cow per day on a DM basis) and PUFA (0.08 kg of Strata and 0.08 kg of Prequel per cow per day on a DM basis). The SFA + MUFA supplement included palmitic and oleic acid. The PUFA supplement included eicosapentaenoic acid, docosahexaenoic acid, and linoleic acid. All cows grazed endophyte-infected tall fescue and were supplemented 2 kg DM per cow per d of soybean hulls for 78 d during late gestation in addition to their treatment supplement. Body condition score and BW were collected at trial initiation, during supplementation, before calving, and after calving. Pen was the experimental unit and BW, BCS, and calf BW were analyzed using the MIXED procedure of SAS. The BW and BCS at trial initiation, during supplementation, before calving, and after calving of the cows supplemented PUFA were not different (P ≥ 0.38) than the BW and BCS of cows supplemented SFA + MUFA. Calf birth BW from cows supplemented with PUFA were not different (P = 0.87) than calf birth BW from cows supplemented with SFA + MUFA. Supplementing cows PUFA during late gestation in fall-calving cows did not affect BW, BCS or calf birth BW.

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