Proc. 57th Southern Pasture and Forage Crop Improvement Conference, Athens, GA April 23-25, 2002

An Update On MaxQ^TM Tall Fescue

John Andrae, Extension Forage Specialist, The University of Georgia

Tall fescue is the most widely grown pasture grass in the eastern United States, occupying more than 35 million acres (Stuedemann & Hoveland, 1988). This species has been called the most important cultivated pasture grass in the USA (Ball et al. 1996) and its popularity is likely related to establishment ease, excellent grazing persistence and long grazing season (Stuedemann & Hoveland, 1988). Many of these desirable attributes are due to the presence of a fungus (Neotyphodium coenophialum) which lives within the plant and is transmitted via seed. Unfortunately, the presence of this wild-type endophyte results in decreased animal gains (Hoveland et al., 1983) and reproductive rates (Peters et al. 1992). In 1993 fescue toxicosis was conservatively estimated to cost the beef industry over $600 million annually (Hoveland, 1993).

Much attention has been placed on preventing fescue toxicosis by removing the wild-type ergot alkaloid producing endophyte from seed and establishing an endophyte-free stand of tall fescue. Although endophyte-free tall fescue does not negatively affect the growth rate or reproduction of grazing animals, it is relatively intolerant of drought and heavy defoliation (Hill et al., 1991, Bouton et al., 1993) which frequently results in stand failure. Recently, endophytes which produce nil ergot alkaloids have been inserted into tall fescue varieties. The presence of these non-ergot alkaloid producing endophytes do not reduce animal performance, but improve plant persistence (Bouton et al., 2002). One of these “friendly” endophytes is currently commercially available under the brand name MaxQ^TM and is marketed in Jesup and Georgia 5 tall fescue varieties by Pennington Seed of Madison, Georgia. The purpose of this paper is to briefly outline plant persistence and animal performance of MaxQ endophyte-infected tall fescue pastures.

Plant persistence:
Persistence of MaxQ^TM tall fescue must be better than that of endophyte-free tall fescue to justify higher seed costs and encourage toxic tall fescue renovation. To test persistence under harsh conditions and promote rapid treatment separation, Bouton et al. (2002) established Georgia 5 and Jesup tall fescue in a bermudagrass sod. Each tall fescue variety was either endophyte-free or contained a wild-type or non-toxic endophyte strain. Plots were grazed throughout two summers in central Georgia to evaluate endophyte effects on plant persistence. After one summer of grazing, MaxQ^TM infected varieties persisted equally as well as wild-type endophyte infected counterparts and were more persistent than endophyte free checks (Table 1). Following two years of grazing, Jesup MaxQ^TM was still as persistent as the wild-type endophyte; however, Georgia 5 MaxQ^TM had stands intermediate to wild-type endophyte and endophyte free counterparts.

Lang et al. (2001) reported that MaxQ^TM tall fescue persisted as well as wild-type infected varieties when grazed by beef cattle in Mississippi although all endophyte types decreased throughout the abnormally hot and dry summer. Both wild-type and non-toxic infected varieties showed greater stand persistence than endophyte free checks. No difference in persistence was observed between Georgia 5 MaxQ^TM and Jesup MaxQ^TM.

Multiple on-farm demonstration plots containing MaxQ^TM and endophyte-free tall fescue have been established throughout north Georgia. While no formal measurements of stand density have been collected on these demonstration plots, plots visually demonstrate improved plant persistence for MaxQ^TM infected varieties versus endophyte-free check strips. Structured surveys of stand density are planned to document MaxQ^TM persistence in these on-farm plots.

Animal performance:
Several animal performance studies have been conducted to determine gain responses to MaxQ^TM tall fescue. Results from initial lamb grazing trials conducted from spring 1998 to autumn 2000 near Eatonton, Georgia were reported by Parish (2001). Lambs grazing wild-type endophyte infected tall fescue exhibited signs of heat stress, elevated rectal temperatures, and depressed serum prolactin levels when compared to lambs grazing endophyte-free and MaxQ^TM tall fescue. Animal gain per head and per acre were also depressed when toxic endophyte infected tall fescue was grazed. Lamb performance did not differ between MaxQ^TM and endophyte-free paddocks. Bouton et al. (2000) and Watson et al. (2001) reported results of a cow-calf grazing trial conducted in northwest Georgia. In this study, two 18 acre replicates of Georgia 5 wild-type and MaxQ^TM tall fescue were grazed from March through November in 2000 and 2001. In both years, cows grazing MaxQ^TM tended to have higher body condition scores and bodyweights at the end of the trial. Weaning weights of calves raised on MaxQ^TM tall fescue were greater than calves raised on wild-type infected tall fescue. During the 2000 and 2001,steer and heifer calves raised on MaxQ^TM paddocks had heavier weaning weights (P < 0.05) than contemporaries grazing toxic tall fescue (Table 2).

Performance of stocker cattle grazing MaxQ^TM was reported by Parish (2001) for cattle grazing locations in central and northwest Georgia. Data are reported in Table 3 for the central Georgia location. Stockers grazing toxic endophyte infected tall fescue exhibited increased rectal temperatures and depressed serum prolactin, average daily gain and gain per hectare. Stocker growth and gain per acre for cattle grazing MaxQ^TM tall fescue was equal to endophyte free tall fescue and superior to wild-type endophyte infected tall fescue in the autumn grazing periods. In the spring season, gains of from Jesup MaxQ^TM were lower than Jesup endophyte-free and Georgia 5 MaxQ^TM, but higher than Jesup wild-type tall fescue. Georgia 5 MaxQ^TM had equal gains to endophyte-free Jesup. Studies from many other locations including another Georgia site (Table 4) and several Southeast states report that MaxQ^TM pastures support gains equivalent to endophyte-free tall pastures (Parish et al, 2001; Lang et al., 2001; Waller et al., 2001). Behavioral data and serum prolactin levels also do not indicate any signs of fescue toxicosis for beef cattle grazing MaxQ^TM. In combination, these studies suggest that MaxQ^TM tall fescue has very few, if any, negative effects on stocker cattle growth.

Following three of the Georgia stocker grazing studies, cattle grazing MaxQ^TM, endophyte-free and wild-type endophytes were finished on high-concentrate diets (Duckett et al., 2002). Subsequent feedlot performance of cattle that grazed MaxQ^TM, endophyte-free and toxic endophytes indicate no difference in animal performance, feed efficiency or most carcass quality measurements between endophyte groups. However, cattle that grazed endophyte-free and MaxQ^TM paddocks entered the feedlot heavier and had heavier carcass weights after an equal time on feed. This, in combination with higher quality grades, resulted in a $108 per head advantage for MaxQ^TM versus toxic endophyte pastured cattle.

Mares in late gestation are particularly sensitive to alkaloids produced by wild-type endophytes. To date, there is limited research studying the effects of MaxQ^TM tall fescue on mare performance in late gestation and early lactation. Ryan et al. (2001) conducted a study in which five mares grazed each of MaxQ^TM, endophyte-free and toxic tall fescue pastures. Of the mares that grazed wild-type tall fescue, 80% were reported agalactic, 40% had compromised deliveries, 60% had retained placentas, and one mare (20%) aborted. No problems were noted for mares grazing endophyte-free or MaxQ^TM tall fescue. Mares grazing wild-type endophyte infected pastures also had a longer gestation period and thicker placental membranes than mares that grazed MaxQ^TM or endophyte-free fescue pastures. These findings led the researchers to suggest that the risk to pregnant mares grazing non-toxic, endophyte-infected tall fescue is minimal or nonexistent. The number of mares in each treatment is, however, limited and more mares should be foaled on MaxQ^TM pastures to confirm these results.

Summary:
Tall fescue varieties containing the MaxQ^TM endophyte produce animal gains similar to endophyte-free tall fescue with plant persistence that approaches or equals wild-type endophyte infected tall fescue. This makes MaxQ^TM tall fescue an attractive alternative to either toxic or endophyte-free tall fescue for pasture establishment and renovation.

Literature Cited:

Ball, D.M., C.S. Hoveland, and G.D. Lacefield. 1996. Southern Forages. 2^nd Edition. Potash and Phosphate Institute. Norcross, GA.

Bouton, J.H., R.N. Gates, D.P. Belesky, and M. Owsley. 1993. Yield and persistence of tall fescue in the southeastern Coastal Plain after removal of its endophyte. Agron. J. 85:52-55.

Bouton, J.H., G.C.M. Latch, N.S. Hill, C.S. Hoveland, M.A. McCann, R.H. Watson, J.A. Parish, L.L. Hawkins, and F.N. Thompson. 2002. Re-infection of tall fescue cultivars with non-ergot alkaloid producing endophytes. Agron. J. (In press).

Bouton, J. J. Bondurant, N. Hill, R. Gates, L. Hawkins, C. Hoveland, M. McCann, F. Thompson, and R. Watson. 2000. Alleviating tall fescue toxicosis problems with non-toxic endophytes. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. October 16-17, 2000. pp. 9-15.

Duckett, S.K., J.G. Andrae, D.R. Gill and M.A. McCann. 2002. Effect of grazing tall fescue endophyte types on subsequent feedlot performance and carcass quality. University of Georgia Animal and Dairy Science Annual Report (In press).

Hill, N.S., D.P. Belesky, and W.C. Stringer. 1991. Competitiveness of tall fescue as influenced by Acremonium coenophialum. Crop Sci. 31:185-190.

Hoveland, C.S. 1993. Importance and economic significance of the Acremonium endophytes on performance of animals and grass plants. Agr. Ecosyst. Environ. 44:3-12.

Hoveland, C.S., S.P. Schmidt, C.C. King, Jr., J.W. Odom, E.M. Clark, J.A. McGuire, L.A. Smith, H.W. Grimes, and J.L. Holliman. 1983. Steer performance and association of Acremonium coenophialum fungal endophyte on tall fescue pastures. Agron. J. 75:821-824.

Lang, E., R. Elmore, M. Salem, A. Tokitkla, and R. Given. 2001. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. November 5-6, 2001.

Parish, J.A. 2001. Use on non-toxic endophyte technology in tall fescue forage systems: Impacts on beef cattle production and grazing behavior. Ph.D. Dissertation. The University of Georgia, Athens.

Parish, J., R. Watson, M. McCann, C. Hoveland, and J. Bouton. 2001. Stocker cattle growth performance trials. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. November 5-6, 2001.

Peters, C.W., K.N. Grigsby, C.G. Aldrich, J.A. Paterson, R.J. Lipsey, M.S. Kerley, and G.B. Garner. 1992. Performance, forage utilization, and ergovaline consumption by beef cows grazing endophyte fungus-infected tall fescue, endophyte fungus-free tall fescue, and orchardgrass pastures. J. Anim. Sci. 70:1550-1561.

Ryan, R., B. Rude, B. Warren, L. Boyd, D. Lang, D. Scruggs, and R. Hopper. Effects of exposing late-term pregnant mares to toxic and non-toxic endophyte-infected tall fescue pastures. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. November 5-6, 2001.

Stuedemann, J.A., and C.S. Hoveland. 1988. Fescue endophyte: History and impact on animal agriculture. J. Prod. Agric. 1:39-44.

Waller, J.C., H.A. Fribourg, R.J. Carlisle, K.D. Gwinn, G.C.M. Latch, L.R. Fletcher, R.J.M. Hay, H.S. Easton and B.A. Tapper. 2001. Evaluation of tall fescues with nontoxic endophytes. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. November 5-6, 2001.

Watson, R., J. Parish, M. McCann, C. Hoveland, and J. Bouton. 2001. Productivity of cow-calf pairs grazing eigher toxic or MaxQ^TM tall fescue pastures. SERAIEG-8 Tall Fescue Toxicosis Workshop. Chapel Hill, TN. November 5-6, 2001. pp. 9-11.

 

Table 1. Summer survival of two tall fescue cultivars with different Neotyphodium coeniphialum endophyte strains. All cultivars planted into bermudagrass and grazed during April-November 1998-1999 at Eatonton, GA. From Bouton et al. 2002.

		Sampling Date
Cultivar	Endophyte Strain	5-7-98	5-18-99	12-7-99
		——————	% stand	——————
Jesup	E+	97.8	74.3	47.5
Jesup	E-	95.5	29.1	10.7
Jesup	MaxQTM	93.7	85.7	38.5
Georgia 5	E+	95.7	66.0	41.7
Georgia 5	E-	94.8	22.2	9.5
Georgia 5	MaxQTM	93.3	62.5	24.7
LSD (p<0.05)		NS	15.9	10.3

 

Table 2. Serum prolactin and weaning weights of steer and heifer calves raised on either wild-type or MaxQ^TM-infected tall fescue pastures. Cattle grazed from approximately April-December in 2000 and 2001. Adapted from Bouton et al., 2000 and Watson et al., 2001.

	Wild-type heifers	MaxQTM heifers	Wild-type steers	MaxQTM steers
Serum prolactin (ng/ml)	30.6 b	88.8 d	18.2 a	75.3 c
Weaning weight lbs	474a	524b	515ab	575c

Serum collected at 120 d of age and reported for year 2000 only. Wild-type endophyte calves include all animals from 2000 and “short-term” treatment in 2001 for a conservative pooled estimate. Numbers within a row with uncommon superscripts differ (P < 0.05).

Table 3. Average daily gains and gain per acre of stocker steers grazing various endophyte strains at Eatonton, GA. Autumn 1999-spring 2001. From Parish, 2001.

	Average Daily Gain, lb	Gain per acre, lb
Autumn
Jesup MaxQTM	2.05a	188a
Jesup endophyte-free	2.27a	210a
Jesup wild-type	1.47b	136b
Georgia 5 MaxQTM	2.24a	208a
Spring
Jesup MaxQTM	1.76b	250b
Jesup endophyte-free	2.20a	313a
Jesup wild-type	0.81c	118c
Georgia 5 MaxQTM	2.16a	307a

Within column and season, means without a common superscript differ (P < 0.05)

Table 4. Average daily gains and gain per acre of stocker steers grazing various endophyte strains at Calhoun, GA. Autumn 1999-Spring 2001. From Parish et al., 2001.

	Average Daily Gain, lb	Gain per acre, lb
Autumn
MaxQTM	1.52a	180ab
Endophyte-free	1.61a	198a
Wild-type	1.06b	142b
Spring
MaxQTM	2.09a	486a
Endophyte-free	2.07a	483a
Wild-type	0.99b	252b

Within column and season, means without a common superscript differ (P < 0.05)