Zilpaterol hydrochloride improves feed efficiency and changes body composition in nonimplanted Nellore heifers1

Abstract

This research aimed to evaluate the effects of zilpaterol hydrochloride (ZH; MSD Animal Health, São Paulo, SP, Brazil) on the performance, carcass traits, serum metabolites, body composition, and gain composition of nonimplanted Nellore heifers. Nellore heifers ( = 72; average BW = 267 ± 16 kg; average 18 mo of age) were maintained in a feedlot system for 118 d. Heifers were separated into 2 groups: Control and ZH. The ZH group received ZH (8.3 mg/kg diet DM) for 30 d with 3 d of withdrawal before slaughter. Heifers were allotted to 18 pens, 9 pens per treatment, and assigned to a randomized block design. The animals were weighed, blood samples were collected, and subgroups of heifers were slaughtered at the beginning of supplementation and after 20 and 33 d to evaluate performance, blood metabolites, empty BW (EBW), and EBW composition. Hot carcass and kidney-pelvic fat weights were recorded at slaughter. At 24 h postmortem, carcasses were fabricated and the 9-10-11th rib (HH) section was removed from the primal rib to analyze moisture, protein, ash, and ether extract (EE) content in empty body (EB) and gain composition. Heifers fed ZH had gains in HCW that were 19.7 kg greater than controls, reflecting the 30% increase ( < 0.01) in ADG. There was no change in DMI, resulting in a 20% greater G:F ratio ( < 0.01) for heifers fed ZH. Heifers supplemented with ZH had carcass dressing percentages that were 3% greater than controls ( < 0.01), and there was also a 19% reduction in kidney-pelvic fat ( = 0.05) in ZH-treated heifers. Zilpaterol increased serum creatinine ( < 0.01), tended to increase ( = 0.06) serum triacylglycerol, decreased serum NEFA ( = 0.04), and tended to decrease ( = 0.06) serum glucose. The EBW composition was changed after 20 d of ZH supplementation ( = 0.02), with ZH increasing the moisture, ash, and protein contents, whereas carcass fat was decreased by ZH by 14%. Consequently, the carcass CP:EE ratio after 20 d was increased ( = 0.03) by 24% with ZH supplementation. There was no change on EBW composition after 30 d of ZH supplementation ( = 0.17). Regarding carcass gain composition, ZH increased EBW gain ( = 0.02) by 842 g/d from d 0 to d 30, EB protein gain by 221 g/d ( = 0.05) from d 0 to d 20, and by 180 g/d ( = 0.01) from d 0 to d 33. In conclusion, ZH supplementation in nonimplanted Nellore heifers altered the composition of body weight gain, promoting greater lean tissue deposition and improving feed efficiency.

Roughage-free finishing diet based on whole corn grain and a mixture of additives for Nellore heifers

“…Furthermore, the values were within the standards observed in studies using high-grain diets for finishing beef cattle (Bohrer et al, 2014;Cônsolo et al, 2014Cônsolo et al, , 2015Genther-Schroeder et al, 2016;Contadini et al, 2017). It is worth noting that the results for rump fat were higher than those for fat thickness, since the deposition of adipose tissue begins from the end towards the middle of the carcass.…”

Postnatal β2 adrenergic treatment improves insulin sensitivity in lambs with IUGR but not persistent defects in pancreatic islets or skeletal muscle

“…In near-term IUGR fetuses and in 3-week-old IUGR lambs, we have shown that expression of ADRβ2 mRNA is downregulated in adipose tissue and skeletal muscle Yates et al 2012a). This ADRβ2 deficiency could explain restricted growth and muscle accretion in IUGR offspring because stimulation with ADRβ2 agonists repartitions nutrients in growing animals to support anabolic protein accretion and energy-producing oxidative pathways (Byrem et al 1998;Consolo et al 2015;Cadaret et al 2017). Furthermore, deficiencies in glucose oxidation in IUGR fetal sheep and in adult humans born SGA from IUGR coincide with impaired proximal insulin signalling that may reflect the loss of counter-regulatory effects of adrenergic signalling (Hadcock et al 1992;Morisco et al 2005;Ozanne et al 2005; Thorn et al 2009).…”

Interaction between supplemental zinc oxide and zilpaterol hydrochloride on growth performance, carcass traits, and blood metabolites in feedlot steers1

“…In the meta-analysis conducted by Lean et al (2014), ZH supplementation increased HCW, LM area, and dressing percentage, whereas it decreased 12th-rib fat thickness. Plasma components related to nitrogen metabolism (plasma urea nitrogen [PUN]) have either decreased (Parr et al, 2014) or remained unchanged (Cônsolo et al, 2015) in response to ZH, whereas plasma constituents related to carbohydrate metabolism (i.e., glucose and lactate) were unaffected (Van Bibber-Krueger et al, 2015).…”