The literature pertaining to the effect of forage-and grain-based feeding systems on beef quality has been reviewed in light of considerable interest in New Zealand regarding the relative merits of grain-and grass-based beef finishing systems. In particular, fifteen experiments which compared forage-and grain-finished beef at the same carcass weight or degree of fatness, have been selected from the literature. When compared at similar carcass weights or the same degree of fatness, the type of feeding system had no effect per se on tenderness, juiciness, lean meat colour, marbling, or pH. In eight out of twelve experiments where flavour was assessed, panellists could not distinguish an effect of diet on flavour. Effects on fat colour were variable and, in six of the nine experiments where fat colour was measured, grain feeding failed to "improve" fat colour. It is concluded that there is little scientific justification for the claim that grain feeding is necessary to produce high quality beef. Beef of comparable quality can be obtained from cattle finished on forage-based diets (i.e., pasture) provided that acceptable carcass weights and degrees of finish can be achieved at a young age.

No abstract

No abstract

No abstract

Two serial slaughter experiments were conducted to compare the liveweight gain and carcass quality of 3-year-old Angus steers finished on concentrate-based rations with steers finished on high quality spring pasture in New Zealand. Experiment 1 used a feedlot ration of 70% maize grain and 30% pasture silage and Experiment 2 used barley instead of maize. In both experiments, steers were adjusted to the concentrate ration prior to being fed ad libitum for 12 weeks.Finishing regime led to a significant difference in carcass weight in Experiment 1 (363 and 407 kg for pasture and grain, respectively). There was no significant difference in final carcass weight in Experiment 2. There was no significant effect of feeding regime on marbling in either experiment. Although grain-finishing significantly affected pH in Experiment 1, there were no treatment effects on tenderness in either experiment, and resident New Zealand panellists were unable to detect sensory differences between beef from the two feeding regimes when comparisons were made at the same slaughter time. In both experiments, steers fed the concentrate diet had brighter and redder meat, but this may have been related to the reduced level of exercise of the feedlot group rather than diet per se. Diet had no effect on carcass fat colour A96086 Received 18 December 1996; accepted II June 1998 in Experiment 1 but steers fed the feedlot ration in Experiment 2 had significantly whiter fat colour.In these experiments the effects of short-term grain finishing on meat quality were minor. It was concluded that, provided a high growth rate and adequate level of finish could be achieved, beef produced from pasture finishing was similar in tenderness and taste to beef finished for up to 100 days on a feedlot.

SummaryKinetic studies of Ca metabolism, using 45CaCl32, were carried out on two mature red deer stags during the period of maximum rate of Ca deposition in the antlers. They were offered green-feed oats to provide energy for maintenance; the diet provided approximately 42mg Ca/kg W per day.Ca appeared to be irreversibly lost from the circulation into the antlers and could be treated for kinetic purposes in the same way as loss of Ca from the body in milk. The size of the rapidly exchangeable Ca pool in the body, excluding the antlers, was 0·21 g/kg W, similar to estimates for lactating cattle. Rates of Ca deposition in the antlers of the two stags, calculated from the model of Ca metabolism, were 58·4 and 38·6 mg Ca/kg W per day. Net endogenous loss was 6–7 mg Ca/kg W per day, much lower than estimates available for other ruminant species. Only 25–40% of Ca requirement or 11–24 mg Ca/kg W per day was derived from the diet, suggesting that the availability of Ca in greenfeed oats is much lower than current estimates for forages. Bones removed on completion of the experiment showed evidence of considerable skeletal demineralization.In other stags subjected to stable Ca balances at the same stage of antler growth, while consuming ryegrass-white clover forage, 60–80% of Ca requirement was derived from the diet, with calculated rates of true absorption of 32–46 mg Ca/kg W per day. These rates of Ca absorption are low compared with values observed in other ruminants at times of high Ca demand such as during lactation.

An experiment was carried out to compare the quality of beef produced from Hereford (H), Hereford × Friesian (HF), and Friesian (F) steers grazed together on pasture from weaning. Carcass characteristics, meat quality parameters, and consumer acceptability were compared when the breeds were slaughtered at the same age (H, HF1, Fl) and at the same level of "fatness" (i.e., same biological maturity; H, HF2, F2). H steers reached slaughter weight and fatness at 27 months of age (approx. 610 kg, 6.75 mm fat at 12th rib, respectively) at which time all H, half the Hereford × Friesians (HF1), and half the Friesians (Fl) were slaughtered. The remaining steers (HF2 and F2) continued to graze until they reached a similar level of fatness to H steers and were slaughtered at 29 and 35 months of age, respectively. Growth rates were similar between breeds throughout the trial.

This study looked at ewe effects on the number of lambs reared (litter size and mortality) and lamb 12 week weight (birth weight and growth rate). Over six years, data was collected on 5571 lambs born to around 3390 Romney (R), Finn cross Romney (F x R), East Friesian cross Romney (EF x R) and Poll Dorset cross Romney (PD x R) ewes. Ewe live weights were recorded pre-lambing and 12 weeks post-lambing. Lambs were weighed at birth and 12 weeks post-lambing. Ewe effects played a significant role in affecting the productivity of the system and many effects were cumulative. Over six years, the lambing percentage (lambs born/ewes lambing) was 165 %. Two tooth ewes had lower lambing percentages than the mixed age ewes (155 vs 170 %). Lambing percentages were 186 % for F x R, 171 % for the EF x R, 155 % for the PD x R and 153 % for the R ewes. Birth weights ranged from 1 kg to 9.8 kg, with a mean of 4.8 kg. Lambs born to F x R ewes (4.28 kg) were significantly lighter at birth than those born to PD x R ewes (5.34 kg). On average, 5 % of lambs were dead at tagging and 11 % of all lambs born were not present at 12 wks of age. The relationship between birth weight and mortality differed to previously published New Zealand reports with high survival rates in the present study over a wide range of birth weights from 3 to 9 kg. It is likely that changes in management practices (improved nutrition, heavier ewes, and selection for easy care lambing) may have contributed to the reduced mortality rates in the heavier lambs in the present study. Ewe genotype modified the effect of birth rank on birth weight and mortality. The average penalty for each additional lamb was smaller for the progeny of the EF x R and F x R ewes (0.85 and 0.88 kg, respectively) than for the progeny of the R and PD x R ewes (1.09 and 1.17 kg, respectively). Triplets born to R ewes had significantly lower survival rates than the other lambs. Heavier birth weights are likely to result in heavier lambs at 12 weeks of age that can be sold earlier. Keywords: birth rank, birth weight, ewe breed, lamb growth, lamb survival