Daily and alternate day supplementation of urea or biuret to ruminants consuming low-quality forage: I. Effects on cow performance and the efficiency of nitrogen use in wethers1,2

Abstract

Two experiments were conducted to determine the influence of supplemental nonprotein N (NPN) provided daily (D) or every other day (2D) on ruminant performance and N efficiency. Treatments included an unsupplemented control (CON) and a urea (28.7% CP) or biuret (28.6% CP) supplement provided D or 2D at 0700. In Exp. 1, five wethers (39 +/- 1 kg BW) were used in an incomplete 5 x 4 Latin square with four 24-d periods to determine the influence of supplemental NPN source and supplementation frequency (SF) on the efficiency of N use in lambs consuming low-quality grass straw (4% CP). The amount of CP supplied by each supplement was approximately 0.10% of BW/d (averaged over a 2-d period). In Exp. 2, 80 Angus x Hereford cows (540 +/- 8 kg BW) in the last third of gestation were used to determine the effect of NPN source and SF on cow performance. The NPN treatments were formulated to provide 90% of the estimated degradable intake protein requirement. The supplemented treatments received the same amount of supplemental N over a 2-d period; therefore, the 2D treatments received double the quantity of supplemental N on their respective supplementation day than the D treatments. In Exp. 1, total DM, OM, and N intake; DM, OM, and N digestibility; N balance; and digested N retained were greater (P < 0.03) for supplemented than for CON wethers, with no difference (P > 0.05) between NPN sources or SF. Plasma urea-N (PUN) was increased with N supplementation compared with CON (P < 0.01), and urea treatments had greater PUN than biuret (P < 0.01). In addition, PUN was greater (P = 0.02) for D than for 2D treatments. In Exp. 2, pre- and postcalving (within 14 d and 24 h after calving, respectively) cow weight and body condition score change were more positive (P < 0.05) for supplemented groups than for CON. These results suggest that supplements containing urea or biuret as the primary source of supplemental N can be effectively used by lambs and cows consuming low-quality forage, even when provided every other day.

Effect of concentrate and urea molasses mineral block (UMMB) supplementation on the growth and feed consumption of Mecheri lambs under intensive rearing

“…Urea molasses products/ UMMB has been suggested a versatile supplement for sheep and goat by many earlier researchers (Golluscio et al, 1998;Currier et al, 2004). Since there was no significant difference in the body weights between concentrate supplemented (T 1 ) and UMMB supplemented (T 2 ) groups at the end of the experiment, it can be inferred that UMMB could be successfully used to replace the concentrate feed for sheep.…”

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

“…Supplementation frequency had little or no effect on VFA concentrations in comparison with daily supplementation. Similarly, other authors (Farmer et al, 2001;Currier et al, 2004;and Morais et al, 2009) have reported that two-day supplementation intervals (or shorter) had some or no effect on VFA. Morais et al (2009) observed that ruminal fermentation parameters (pH, NH 3 -N and VFA) in Nellore steers on Brachiaria brizantha pastures were stable when supplementation was reduced from seven to five or three times per week; they concluded that the maintenance of these parameters was important for adequate ruminal fermentation.…”

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

“…Beaty et al (1994), Farmer et al (2004) and Currier et al (2004), demonstrated that ruminants consuming low quality forages/pastures, and supplemented less than once daily, are able to maintain BWG, effi ciency of DM use, nitrogen and other nutrients, and effi ciency of microbial synthesis, as compared with animals supplemented once daily. However, studies dealing with the effects of reduced supplementation frequency in cattle grazing tropical pastures are scarce, as a result of the number and complexity of variables to be taken into account under the conditions prevailing.…”