Impact of Weighing Procedures and Variation in Protein Degradation Rate on Measured Performance of Growing Lambs and Cattle

Abstract

A lamb growth trial was conducted to evaluate soybean meal and blood meal and to compare two experimental designs (a completely randomized design and a switchback design). A larger amount of variation was observed with the switchback than with the randomized design. A larger number of animals, longer treatment period or increased number of weighings may be needed to overcome end point weighing errors and decrease the variation in the switchback design. In both designs, there was a significantly greater conversion of protein to gain for blood meal (BM)-supplemented lambs than for soybean meal (SBM)-supplemented lambs. The relative value of BM compared with SBM was 251% (completely randomized design) or 296% (switchback design). Weighing steers 2 or 3 d at the beginning and end of the trial reduced variation and increased the probability of detecting differences in daily gain, gain/feed and protein efficiency when compared with a standard weighing method (once at the beginning and once at the end of the trial). Regressing 11 weekly weights on an average of one, two or three initial and final weights also reduced variation and increased the probability of detecting treatment differences. Regressions of weekly weights were more useful as the number of initial and final weights was decreased. Daily gain and gain/feed increased linearly (P less than .05) with protein level when BM or SBM was fed. A nonlinear model was used to predict protein requirement, maximum gain and relative protein values. There was a range in relative values for BM of 255 to 348% depending on the method of analysis used.

Effect of essential oils, tylosin, and monensin on finishing steer performance, carcass characteristics, liver abscesses, ruminal fermentation, and digestibility1

“…Steers were received from a variety of sources (auction markets and ranch direct) from Octo- Steers were returned to the University of Nebraska research feedlot (Mead, NE) on September 9, 2005 where they were penned and fed a diet of 50% alfalfa hay, 25% wet corn gluten feed, and 25% rye distillers grains (DM basis) until study initiation. Five days before study initiation (September 19, 2005), steers were limit fed at 2% of BW daily to minimize variation in gastrointestinal fill (Stock et al, 1983). On d 0 and 1, steers were individually weighed in a Silencer chute (Moly Manufacturing Inc., Lorraine, KS) suspended on load cells (Avery Weigh-Tronix, Fairmont, MN) and the mean BW was used to determine initial BW.…”

Prediction model of a joint analysis of beef growth and carcass quality traits

“…It was contended that live weight may often be an unreliable indicator of empty body mass (Owens et al, 1995), due to large variations in gut fill (Stock et al, 1983), animal movement on the scales and the effects of diet switches on estimation of live weight (Tolley et al, 1988). Inaccurate or biased estimates of body weight can mask effects of treatments, leading to wrong conclusions with potentially significant economic ramifications (Owens et al, 1995).…”

Effects of the level and source of dietary protein on intake and milk yield in dairy cows

“…In ruminants, increasing the protein content of the diet enhances DMI, milk yield and body weight gain [3,20], but the responses vary greatly according to the type and level of protein supplements. The supplementation of diets with non-degradable protein improves milk yield in dairy cows [1,7,13], but DMI responses vary among the different trials [11,14,26].…”