Effects of animal type (wild vs. domestic) and diet alfalfa level on intake and digestibility of European adult rabbits (Oryctolagus cuniculus)

The aim of this study was to evaluate the effect of the level of alfalfa in the diet on feed intake and digestibility of two types of rabbits, wild (Oryctolagus cuniculus algirus) vs. domestic (O. cuniculus cuniculus). Ten wild (W; mean LW = 927 g) and 10 domestic (D; mean LW = 4,645 g) adult rabbit does were fed ad libitum two pelleted diets: a control diet (C) with 15% of dehydrated alfalfa hay (as feed basis) and a test diet (A) with 36% of dehydrated alfalfa hay (as feed basis), according to a change-over design. Wild does dry matter (DM) intake per kg live weight (BW) was 55% higher (p < .001) than the intake of the D ones (58 g vs. 37 g DM per kg BW respectively). However, no difference (p > .05) was found when intake was expressed per kg^0.75 BW (ca. 56 g DM) and tended to be higher (p = .07) in D does when expressed per kg^0.67 BW (62 g vs. 55 g DM). Domestic does showed a higher (p < .05) DM, organic matter, crude energy and neutral detergent fibre digestibility (3; 2; 3; 3 percentage points respectively) than W does. The amount of nutrients and energy digested by D does was lower per kg BW (p < .001), similar per kg^0.75 BW (p > .05) and tended to be higher per kg^0.67 BW (p < .1) than in W does. The diet content of alfalfa did not affect (p > .05) the feed intake nor the diet digestibility. This study suggests that W rabbits exhibit a higher intake per kg BW and a lower digestibility than their D counterparts, which results in similar digestible nutrient and energy intake per kg BW powered to 0.75. The nutritive value of dehydrated alfalfa for rabbits, evaluated through intake and digestibility, seems to be equivalent to their base diets (forage plus concentrate).

Comparative digestibility of low-quality grass hay by two breeds of cattle differing in mature live weight

The digestive capacity of the Portuguese native breed of Barrosão cattle and the Holstein-Friesian breed was measured when fed meadow hay (72-74 g CP and 641-671 g NDF/kg dry matter), offered either alone or supplemented with soya bean meal (150 g/kg dry matter), at maintenance level. Four mature cows of each breed were used. Average initial live weight (LW) was 457 and 635 kg for the Barrosão and the Holstein-Friesian cows respectively. The organic matter digestibility (OMD) of the meadow hay was higher in Holstein-Friesian than in Barrosão cows (p < 0.08) whether supplemented or not. The neutral detergent fibre digestibility of the hay was also higher in Holstein-Frisian when the hay was fed alone (p < 0.08). The soya bean meal supplementation increased the OMD and the NDFD digestibility of the total diet (p < 0.05), but not the OMD digestibility of the hay (p > 0.05). The results obtained in this study suggest a higher ability to digest fibre in the large dairy breed than in the small native breed. This suggestion is also supported by previous findings with sheep breeds largely differing in mature live weight.

Effects of ambient temperature and soybean meal supplementation on intake and digestion of two sheep breeds differing in mature size

The aim of this study was to compare the intake and digestive physiology of mature ewes of two breeds--Ile-de-France (mature weight: 75-80 kg) and Churra-da-Terra-Quente (CTQ; mature weight: 45-50 kg)--and evaluate the effects of ambient temperature and protein supplementation in the comparison. The temperature (25 °C vs. 11 °C) and soybean meal supplementation (150 g/kg of ingested hay on dry matter basis vs. unsupplemented control) were evaluated in 48 adult ewes of two breeds fed hay ad libitum and at a restricted level of intake. The intake, digestibility, rumen pH and NH(3)-N, rumen outflow rates, faeces particle size and thyroid hormones levels were measured. These hormones can be related with gastrointestinal motility, thus explaining rumen outflow rate patterns. Dry matter intake per kg of body weight was higher in CTQ ewes (p < 0.05). This breed also exhibited lower organic matter and neutral detergent fibre digestibility (p < 0.001) and higher solid (p < 0.001) and liquid (p < 0.01) rumen outflow rates irrespective of intake level, supplementation or temperature. Rumen pH remained above 6.6 in all treatments. NH(3)-N rumen content was similar (p > 0.05) when breeds were fed only hay. There was no breed effect (p > 0.05) on faeces particle size. Triiodothyronine was not affected (p > 0.05) by breed and thyroxine was higher (p < 0.10) in the CTQ breed but only at the lower temperatures (breed × temperature, p < 0.05). Ile-de-France sheep showed a lack of adaptation to lower temperatures. This study suggests that the native CTQ breed fulfils its metabolic needs by having a higher intake and inherits faster flow through the gastrointestinal tract, as a result, its digestive ability is diminished.