Effects of Fescue Endophyte and Interseeded Clovers on Subsequent Finishing Performance of Steers

Abstract

Stocker cattle (Bos spp. L.) performance has been adversely affected on tall fescue (Festuca arundinacea Schreb.) pasture infected with the endophyte (Acremonium coenophialum Morgan‐Jones and Gams). Grazing results, however, cannot be completely evaluated until the carryover effects on the animal are evaluated through the feedlot phase to the final product, the carcass. In this study 60 Angus (B. taurus L.), Brahman (B. indicus L.)‐Angus, Angus × Braham‐Angus, and Simmental (B. taurus L.) × Brahman‐Angus, 12‐ to 19‐mo‐old steers in 1987, and 54 in 1988, were used to study effects of grazing ‘Kentucky 31’ tall fescue on subsequent feedlot performance. Steers had been grazing fescue pastures from November to May. The pasture treatments were: (i) high endophyte (HE) with 76% infected fescue; (ii) HE with 74% infected fescue interseeded with a mixture of clovers (HE + Clo); and (iii) low endophyte (LE) with 0.7% infected fescue. Steers were removed from these pastures in eastern Oklahoma on 21 May, held for 6 d on bermudagrass [Cynodon dactylon (L.) Pers.]‐ryegrass (Lolium multiflorum Lam.) pastures and shipped 450 mi to a feedlot in western Oklahoma. Steers were then fed for 117 or 113 d (years 1987 and 1988, respectively) and slaughtered. No treatment × year interaction was noted and data were pooled across years. The HE steers weighed 101 lb less than LE steers at the end of grazing, but HE steers gained 66 lb more during the feedlot phase than LE steers. The HE steers gained faster during the 6‐d holding period, tended to lose less weight in transit to the feedlot, and gained faster during the first 48 or 49 d (years 1987 and 1988, respectively) in the feedlot. Steers which had been grazing HE + Clo pastures gained similarly to LE steers in the feedlot. The HE + Clo steers had heavier final body and carcass weights than LE steers because of slightly greater gains on pasture and in the feedlot, plus greater gains during the 6‐d holding period. Rectal temperature was higher for HE than for LE at the end of fescue grazing and after the 6‐d holding period. Temperatures of steers that grazed HE + Clo were intermediate. No differences in rectal temperatures were noted the morning following arrival at the feedlot. Carcass weights were lighter and quality grade tended to be lower for HE steers. These results suggest that steers showing clinical signs of fescue toxicosis can compensate for up to 67% of the reduced gains resulting from grazing fescue.

Weaning and post-weaning performance by fall-born calves weaned on different dates from endophyte-infected tall fescue pastures managed with two different rotation frequencies

“…Daily gain during the receiving period (Phase 3) was greater from EARLY compared with LATE during the third year and total intake during the receiving period was greater from EARLY compared with LATE during the second and third years. In previous studies, calves moved from E+ pastures to nontoxic pastures had reduced intake for at least 10 days (Stuedemann et al, 1989), but animal gains during initial periods in a feedlot environment following removal from E+ pastures has been variable (Lusby et al, 1990;Cole et al, 2001b). In the present study, calves weaned LATE required more days to regain their weight lost during the transport and simulated auction in 2 of 3 years.…”

“…Numerous studies have evaluated feedlot performance following a grazing period on E+ fescue. Generally, cattle that previously grazed E+ pastures showed improved gain during a subsequent feedlot period (Coffey et al, 1990;Lusby et al, 1990;Allen et al, 2001;Cole et al, 2001b), but some studies have reported no improvement (Hancock et al, 1987) in feedlot gain or even reduced feedlot gain (Hancock et al, 1988) by calves that grazed E+ pastures previously. However, each of these studies used yearling cattle during post-weaning evaluations on E+ or other non-toxic forages.…”

“…No advantage in calf weights was detected from a twice weekly compared with a twice monthly rotational grazing system. Body weight gain by calves grazing E+ pastures has been consistently lower compared with calves grazing non-toxic pastures, but the effects of grazing E+ on subsequent animal performance have been variable (Cole et al, 2001b;Hancock et al, 1988;Coffey et al, 1990;Lusby et al, 1990). Furthermore, weaning age and post-weaning management also may impact long-term calf performance (Myers et al, 1999a,b;Thrift and Thrift, 2004;Sexton et al, 2005).…”

Fescue toxicosis and its influence on the rumen microbiome: mitigation of production losses through clover isoflavones

“…Lusby et al (1990) found that the inclusion of red clover into stands of tall fescue not only reduced the severity of fescue toxicosis (reduced rectal temperatures and respiration rates) but it improved average daily gain and carcass quality compared to cattle on tall fescue alone. Broderick (1995) noted that the protein content of legumes provided an excellent source of nitrogen for ruminants, citing that red clover compared to alfalfa was more efficient as a source of rumen un-degradable protein (RUP).…”

“…In particular, red and white clover have proven to be most successful at increasing growth and overall gains and mitigating fescue toxicosis (McLaren et al 1983;Lusby et al 1990;Chestnut et al 1991;Beck et al 2012). Lusby et al (1990) found that the inclusion of red clover into stands of tall fescue not only reduced the severity of fescue toxicosis (reduced rectal temperatures and respiration rates) but it improved average daily gain and carcass quality compared to cattle on tall fescue alone.…”