Prediction of manure nitrogen and organic matter excretion for young Holstein cattle fed on grass silage-based diets1

Abstract

The objectives of the present study were to evaluate the effects of sex (steers vs. heifers) of young Holstein cattle on N and OM excretion in feces and urine and to use these data to develop prediction models for N and OM excretion. Data used were derived from a study with 20 autumn-born Holstein cattle (10 steers and 10 heifers) with N and OM intake and output measured at age of 6, 12, 18, and 22 mo, respectively. The cattle were offered a typical diet used on U.K. commercial farms containing a single grass silage mixed with concentrates. In each period, the cattle were housed as a single group in cubicle accommodation for the first 20 d, individually in metabolism units for the next 3 d, and then in calorimeter chambers for the final 5 d with feed intake, feces, and urine excretion measured during the final 4 d. Within each period, sex had no effect (P > 0.05) on N or OM intake or excretion or N utilization efficiency, with exceptions of steers having a greater intake of N (P = 0.036) and OM (P = 0.018) at age of 18 mo and a lower ratio of fecal N:N intake (P = 0.023) at age of 6 mo. A range of regression relationships (P < 0.05) were developed for prediction of N (g/d) and OM (kg/d) excretion in feces and urine. The present data were also used to calculate accumulated N and OM intake (kg) and excretion for the 2 sexes. Sex had no effects (P > 0.05) on accumulated N or OM intake or N or OM excretion in feces and urine or retained N and OM during the first or second year of life. On average for the 2 sexes at first and second year of age, the accumulated N excretions in feces were 11.4 and 21.1 kg and in urine 11.6 and 30.6 kg, respectively, and the corresponding values for accumulated OM excretions were respectively 241.5, 565.7, 30.3 and 81.5 kg. A number of equations were developed to predict accumulated N and OM excretion in feces and urine (kg) using BW (kg; P < 0.001, r(2) = 0.95 to 0.97). The accurate prediction of N and OM excretion in feces and urine is essential for reducing N pollution to ground and surface water and calculating methane and nitrous oxide emissions from manure management of dairy and beef production systems. These data can add novel information to the scientific literature and can be used to improve national inventories of manure N output and greenhouse gas emissions and to develop appropriate mitigation strategies for young Holstein cattle.

Digestion and nitrogen metabolism in beef cattle and in vitro rumen fermentation of autumn grass differing in fertilizer nitrogen application rate

“…The quantities of N retained in the current study (47 g/day) were intermediate to those ranges. Jiao, Yan, and McDowell () reported that the quantity of N retained by Holstein steers offered grass silage‐based diets increased with age from 6 to 18 months (45–64 g/day) and then reduced to 22 months (51 g/day); the steers in the present study were 18 months old. Sánchez Chopa et al () summarizing published N‐use efficiency (NUE) for beef cattle studies reported values ranging from 11% to 42%; the values (25% and 22%) obtained in the current study were intermediate to that range.…”

Chemical composition and nutritive values of cassava pulp for cattle

“…Similarly, Jiao et al. () found linear relationships between N intake and fecal and urinary N. Therefore, feeding cattle with the cassava pulp diet lowered their N intake and this resulted in lower urinary N and retained N levels.…”

Effects of breed, sex, and concentrate supplementation on digestibility, enteric methane emissions, and nitrogen utilization efficiency in growing lambs offered fresh grass1

“…Manure N per N intake was calculated from N intake and output in feces and urine ranging from 84 to 93% in nonlactating cows and ranging from 69 to 73% in lactating cows, respectively (Wilkerson et al, 1997). Jiao et al (2014b) reported manure N outputs in a range of 57 to 76% of N intake in young Holstein cattle. Mikolayunas et al (2011) found manure N of lactating dairy ewes ranging from 72.5 to 86.8% of N intake when offered different percentages of orchardgrass:alfalfa.…”

“…There are positive relationships between daily N intake and fecal and urinary N excretion, respectively. Nitrogen intake has been suggested as a better predictor for fecal and urinary N excretion than other animal and dietary factors such as DMI, dietary CP content, and BW in beef cattle and dairy cows (Waldrip et al, 2013;Dong et al, 2014;Jiao et al, 2014b). Those equations indicate that fecal and urine N are increased by 0.15 and 0.56 g (Waldrip et al, 2013), 0.20 and 0.51 g (Dong et al, 2014), and 0.29 and 0.48 g (Jiao et al, 2014b) with an increase in N intake by 1 g, respectively.…”

“…Nitrogen intake has been suggested as a better predictor for fecal and urinary N excretion than other animal and dietary factors such as DMI, dietary CP content, and BW in beef cattle and dairy cows (Waldrip et al, 2013;Dong et al, 2014;Jiao et al, 2014b). Those equations indicate that fecal and urine N are increased by 0.15 and 0.56 g (Waldrip et al, 2013), 0.20 and 0.51 g (Dong et al, 2014), and 0.29 and 0.48 g (Jiao et al, 2014b) with an increase in N intake by 1 g, respectively. In the current study, the N intake lost as fecal and urine N was increased by 0.27 and 0.41 g, respectively, with an increase in N intake by 1 g. The negative relationship between the efficiency of N utilization and dietary N concentration has also been reported in dairy cows and beef cattle (Monteils et al, 2002;Hristov et al, 2004;Yan et al, 2006;Waldrip et al, 2013).…”