Browsing by Author "Lopez-Villalobos N"
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- ItemCarcass characteristics and meat quality of Hereford sired steers born to beef-cross-dairy and Angus breeding cows.(2016-11) Coleman LW; Hickson RE; Schreurs NM; Martin NP; Kenyon PR; Lopez-Villalobos N; Morris STSteers from Angus, Angus×Holstein Friesian, Angus×Holstein Friesian-Jersey and Angus×Jersey cows and a Hereford sire were measured for their carcass and meat quality characteristics. Steers from the Angus×Holstein Friesian cows had a greater final body weight and carcass weight (P<0.05). Steers from Angus×Jersey cows had the lowest carcass weight and dressing-out percentage (P<0.05). There was a greater fat depth over the rump at 12 and 18months of age for the steers from Angus cows (P<0.05) but, not at 24months of age. The steers had similar meat quality characteristics across the breed groups. Steers from Angus×Holstein Friesian and Angus×Jersey cows had a higher ratio of n6 to n3 fatty acids. Using beef-cross-dairy cows to produce steers for meat production does not impact on meat quality. Using Jersey in the breed cross reduced the carcass tissues in the live weight and the potential meat yield.
- ItemIntake of milk and pasture and growth rate of calves reared by cows with high or low potential for milk production(CSIRO Publishing, 2016-11-29) Roca Fraga FJ; Lopez-Villalobos N; Martin NP; Kenyon PR; Morris ST; Hickson REMilk production of cows influences calf weaning weight, which is the major driver for economic return in a cow–calf operation. The growth trajectory of 64 steer calves resulting from a terminal cross between Angus or Simmental bulls with Angus, Angus cross Holstein Friesian, Angus cross Jersey and Angus cross KiwiCross cows was examined during the pre-weaning period from birth (D0) to weaning (D148) and during the post-weaning period until a year of age (D365). Random regression models were used to model milk intake and liveweight of calves throughout lactation. These models were a good fit to the data (r2 = 0.77 for milk intake and r2 = 0.99 for liveweight). Total energy intake from milk was greater (P < 0.05) for the Angus cross Holstein Friesian-, Angus cross Jersey- and Angus cross KiwiCross-reared steers than for those reared by Angus dams. Additional milk intake increased liveweight of steers from D90 to D365, but the magnitude of the effect decreased as the calves aged. Simmental-sired steers had a greater liveweight response to additional milk intake than Angus-sired steers at D120 and D148, probably reflecting greater growth potential from out-crossed calves.
- ItemThe effect of defoliation frequency and height on plantain and chicory-based swards(2021) Cranston L; Kenyon P; Morris S; Lopez-Villalobos N; Kemp P
- ItemThe effect of repetitive rugby scrummaging on force output and muscle activity(Georg Thieme, 2017-06-01) Cochrane DJ; Harnett K; Lopez-Villalobos N; Hapeta JWDuring rugby scrummaging, front row forwards encounter high levels of force that has been suggested to cause transient fatigue and is likely to reduce subsequent performance. However, little is known about the effect of repetitive scrummaging on force output and onset of fatigue. Twelve male front row forwards (21.5 ± 2.3 yr; height 185.7 ± 4.4 cm; body mass 108.5 ± 7.1 kg) each performed three sets of five maximaleffort isometric scrums for 10 s, with 40 s rest separating each repetition; 2 min recovery was provided between each set. Force output and electromyography (EMG) of the right medial gastrocnemius (MG), biceps femoris (BF), gluteus maximus (GM), erector spinae (ES), rectus abdominis (RA), external oblique (EO), internal oblique (IO), and rectus femoris (RF) were assessed. There was no significant force decrement from performing 15 scrums and no fatigue was detected from EMG median frequency and mean amplitude. For training and practice purposes, coaches and trainers can be confident that 15 individual repetitive static scrums against a machine are unlikely to cause a reduction in force production and promote fatigue. However, the effect of rugbyrelated activities in conjunction with scrummaging requires further research to determine if transient fatigue is causal to scrummaging for subsequent performance