Defining the composition and properties of manure in livestock production is critical in order to minimise possible environmental impacts stemming from its management. In this study, a nitrogen balance was carried out during two identical fattening periods (Experiments 1 and 2) in growing rabbits from weaning (age 28 d and live weight about 0.6 kg) to slaughter (age 61 d and live weight about 1.8 kg). The breeding conditions were typical for Spanish rabbit production. The objectives were to quantify the total nitrogen excreted by the animals and to estimate the average efficiency in the use of this nutrient, in comparison to other species. Animal weight, feed intake, and the production of faeces and urine were monitored weekly in a set of eight cages with nine rabbits in each, performing weekly analyses for nitrogen content in feed, urine and faeces. The overall nitrogen excretion was 50.2 g N per animal in Experiment 1 and 46.9 g N per animal in Experiment 2, which corresponded to about 58% of the total nitrogen intake. Urine and faeces contributed to overall nitrogen excretion in approximately the same proportions. The nitrogen excretion ratio was 40 grams per kilogram of animal produced. According to this ratio, rabbit breeding is less efficient in the use of nitrogen than raising broilers, but more than fattening pigs.

This study assessed the effect of drinker type on water use and slurry characteristics of growing-finishing pigs. A total of 124 crossbred pigs [20 kg of bodyweight (BW)] were allotted to 16 pens (3–4 pigs/pen) in two time periods during the cool season (length: 97 days each). Drinker devices were: (1) pig teat, (2) bite drinker, (3) nipple square bowl, and (4) nipple bowl. There were limited differences among drinker types concerning the growth pattern of pigs during the fattening period, but target BW (100 kg) was similar in all treatments (P > 0.05). Feed intake did not differ among drinker types (P > 0.05). Nipple bowl drinker showed the lowest water disappearance during the experiment, whereas bite drinker showed the greatest values during the late fattening period (P < 0.05). Slurry production did not differ among drinker devices (P > 0.05), but slurry volume increased linearly during the study (P < 0.05). Pigs raised using nipple square and nipple bowl drinkers produced slurry with greater DM content than teat drinkers (P < 0.05). Most of the slurry fertiliser value elements (N-P-K) were significantly affected by drinker type (P < 0.05). Slurry from pigs using teat and bite drinkers had lower N-NH4, total N and K content than that from nipple square and nipple bowl drinkers (P < 0.05). Total N content of slurry on a wet basis decreased during the fattening period (P < 0.05). Improved efficiency in water use by pigs led to greater slurry N and K content, mainly due to the increase in its DM content. A negative association between water use at pig facilities and its slurry fertiliser value was demonstrated.