A preliminary study of growth, serum prolactin and reproductive performance of beef heifers grazing -infected tall fescue

Fanning, M. D.; Spitzer, J.C.; Cross, D. L.; Thompson, F. N.

doi:10.1016/0093-691x(92)90058-y

Cited by 15 publications

(13 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2) may be a major contributing factor to the lack of negative effect on reproductive performance. As with our study, Fanning et al (1992) reported suppressed serum prolactin levels and decreased ADG of heifers grazing E+, but observed no effect of grazing E+ on ovarian activity, synchronized estrous response or pregnancy rate of heifers exposed to E+ for 100 d prior to insemination. Their study was conducted from November to March when alkaloid concentrations are usually low (Kallenbach et al, 2003;Drewnoski et al, 2007) and ambient temperatures are cool.…”

Section: Resultssupporting

confidence: 66%

“…Studies evaluating the effects of E+ on pregnancy rate have been conducted with variable results. Some studies have reported cows or heifers consuming E+ have reduced pregnancy rates (Schmidt et al, 1986;Beers and Piper, 1987;Gay et al, 1988) while others have reported no difference (Fanning et al, 1992;Burke et al, 2001b;Burke and Rorie, 2002;Watson et al, 2004). The discrepancies in E+ effect on pregnancy rate may be related to differences in experimental conditions including the amount of ergot alkaloid consumed and environmental temperature during the breeding period.…”

Section: Resultsmentioning

confidence: 84%

See 1 more Smart Citation

Growth and reproductive performance of beef heifers grazing endophyte-free, endophyte-infected and novel endophyte-infected tall fescue

et al. 2009

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 66%

Section: Resultsmentioning

confidence: 84%

Growth and reproductive performance of beef heifers grazing endophyte-free, endophyte-infected and novel endophyte-infected tall fescue

et al. 2009

View full text Add to dashboard Cite

“…Serum prolactin concentrations were not different between treatments; however, from early summer to late fall, prolactin concentrations decreased. In previous literature, cattle grazing toxic endophyte-infected tall fescue also had experienced this seasonal effect with reduced serum prolactin levels over similar times ( Fanning et al, 1992 ; Aiken et al, 2013 ; Stowe et al, 2013 ; Shoup et al, 2016 ). This indicates that all heifers, in this experiment were experiencing fescue toxicity.…”

Section: Discussionmentioning

confidence: 78%

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

Volk

Kordas

Stokes

et al. 2019

Translational Animal Science

View full text Add to dashboard Cite

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.

show abstract

“…It is possible that the reproductive system of the cow is often robust enough to withstand the effects of grazing E+ tall fescue even when other symptoms such as decreased PRL and BW gain are evident. Fanning et al (1992) observed this in a study with heifers fed E+ tall fescue, which exhibited decreased serum PRL and weight gain without any negative effect on reproductive performance. This also seemed to be the case in the current study, as reproductive performance was generally good in both the E+ and AR542 groups despite lower BW gain, condition score, and serum PRL in the E+ group, indicating that toxicosis was present.…”

Section: Discussionmentioning

confidence: 78%

Productivity of cow–calf pairs grazing tall fescue pastures infected with either the wild-type endophyte or a nonergot alkaloid-producing endophyte strain, AR5421,2

Watson

McCann

Parish

et al. 2004

Journal of Animal Science

View full text Add to dashboard Cite

The nonergot alkaloid-producing endo-phyte, AR542, has been shown to improve the persistence and yield of tall fescue pastures without causing the animal disorders commonly associated with tall fescue toxicosis. A 3-yr grazing study was conducted to compare effects of AR542-infected tall fescue pastures with wild type endophyte-infected (E+) tall fescue pastures on cow-calf performance. Replicated 7.3-ha pastures of each treatment were grazed by cow-calf pairs (16 pairs per pasture replication) each year from March to weaning in September. The cows were exposed to breeding on their respective pasture treatments from April 1 through June 15. The treatment groups were compared for reproductive performance, ADG, BCS, calf growth rate, and weaning weight. Blood samples were also collected for serum prolactin (PRL) analysis. There were no significant differences in calving rate (P = 0.98) or calving interval (P = 0.62) between pasture treatments. Cows that grazed the AR542 pastures subsequently gave birth to calves that were heavier (P < 0.05) than calves from cows that had grazed the E+ pastures. Cows grazing the AR542 pastures had higher (P < 0.05) BCS at the end of the grazing period, and had higher ADG during the grazing period. Calves raised on the AR542 pasture had higher (P < 0.05) ADG and weaning weights than calves of the same sex raised on the E+ pastures. Serum PRL concentrations were decreased (P < 0.05) in both cows and calves on the E+ pastures compared with serum PRL concentrations in cows and calves grazing the AR542 pastures. The results indicate that grazing tall fescue pastures infected with the AR542 endophyte may give significant advantages in cow-calf growth rates and BCS over grazing E+ pastures. However, there did not seem to be any benefit in reproductive performance in this trial. There was a small, but significant increase in birth weight in cows grazing AR542 pasture.

show abstract

A preliminary study of growth, serum prolactin and reproductive performance of beef heifers grazing -infected tall fescue

Cited by 15 publications

References 11 publications

Growth and reproductive performance of beef heifers grazing endophyte-free, endophyte-infected and novel endophyte-infected tall fescue

Growth and reproductive performance of beef heifers grazing endophyte-free, endophyte-infected and novel endophyte-infected tall fescue

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

Productivity of cow–calf pairs grazing tall fescue pastures infected with either the wild-type endophyte or a nonergot alkaloid-producing endophyte strain, AR5421,2

Contact Info

Product

Resources

About