Effect of nocturnal grazing and supplementation on diet selection, eating time, forage intake and weight changes of cattle

Sixty-four Azawak male calves were used to study the effect of nocturnal grazing (NG) and supplementation (S) in the dry season on forage and water intake, faecal output, eating time and weight changes of cattle in the Sahel. Treatments were factorial combinations of four levels of NG (0, 2, 4 and 6 h/day) and two levels of S (0 and 608 g dry matter (DM) per animal per day). All animals were allowed to graze 10 h during the day and were weighed every 2 weeks during the 70-day experimental period. Eight oesophageally fistulated steers were used in a cross-over design to sample the diet (forage) selected during the day and at night by supplemented and non-supplemented animals. Extrusa crude protein and in vitro organic matter digestibility were not influenced by supplementation (P > 0.05). Time spent eating during the day or at night were not affected by supplementation but total eating time increased by 39.4 (s.e. 2.1) min/h of NG. Forage intake increased with increase in NG, while total food intake (forage supplement) increased with supplementation (82.4 v. 92.1 (s.e. 2.4) g DM per kg M0.75 per day). The supplemented animals also drank more water than the non-supplemented (26.2 v. 24.8 l per animal per day). Average live-weight change (LWC) increased by 24.4 (s.e. 8.7) and 9.3 (s.e. 6.2) g/h of NG in non-supplemented and supplemented animals, respectively. Supplementation improved LWC (-107 v. 99 g/day, s.e. 14, P < 0.05). Night grazing improves dry season performance and its effect decreases when cattle are supplemented