Effects of Water and Feed Restriction on Digestion and Metabolism in Nubian Goats

Abstract

Four experiments were carried out with Nubian goats with the objectives of studying the effects of water restriction (experiment 1), feed and water restriction (experiment 2), type of feed (experiment 3) and water or feed restriction (experiment 4) on dry matter intake (DMI), water intake, digestibility of nutrients, ruminal components, blood urea-N (BUN) and some other physiological parameters related to animal performance. All the experiments were conducted at the experimental units of Animal Production Research Department, National Centre for Research located at Soba, Southeast Khartoum (from April 2005 to September 2006). Experiment (1): Nine yearling uncastrated Nubian goats ranging in weights from 14 to 17 kg were used. They were randomly allocated to three treatments with 3 animals per treatment adlib water and feed (control) (T1), water restricted to 50% (T2) and water restricted to 100 % (T3). During the experiment the animals were provided with alfalfa (Medicago Sativa) hay adlibitum. Dry matter intake (DMI), WI, WI: DMI ratio, RT and RR are significantly (P<0.05) affected by water restriction whereas faecal DM output, urine volume are not affected by water restriction DMI decreased more by 100% water restriction than 50% and control. Water restriction had no significant (P<0.05) effect on DMD; OMD and CPD but EED showed a significant (P<0.05) increase with 50% restriction and a significant (P<0.05) reduction in 100% restriction. XVI Water restriction had no significant affect (P>0.05) on ruminal pH, ruminal NH3-N and blood urea nitrogen (BUN), pH and NH3-N also were not significantly affected by sampling time. N-balance and N-intake were affected highly significantly (P<0.01) by water restriction whereas faecal-N and urinary-N were not significantly affected by water restriction. Experiment No. (2): Twelve yearling uncastrated males of Nubian goats ranging in weight from 11.5 to 17.5 kg were used in this experiment. They were allocated at randomly to each of the experimental treatments in 2x2 factorial arrangement of treatments which refered to adlibitum water and feed (control) (T1) adlibitum water and feed restricted to 66.66% from adlibitum (T2), water restricted to 33.3% and feed restricted to 66.66% from adlibitum (T3), and water restricted to 33.3% from adlibitum and feed adlibitum (T4) with three animals per each treatment DMI, WI, urine volume and faeces DM output are significantly (P<0.05) affected by treatments, whereby RT and RR were not, DMI decreased by all treatments compared to adlibitum water and feed (control) urine volume increased (p<0.05) significantly with treatment (T1) (adlib water and feed restricted 66.66% from adlib.) Digestibility of nutrients were not affected (p>0.05) by treatments except CPD which was decreased (p<0.05) significantly by feed restriction and feed and water restriction but not altered by water restriction. Ruminal pH, ruminal NH3.N and BUN were not affected by treatments (p>0.05) except BUN before feeding was significantly (p<0.05) decreased by treatments compared to control. Nitrogen intake was highly XVII (p<0.01) significantly affected by treatments that it decreased by treatments. Also faecal N and N balance were significantly affected (p<0.05) by treatments, on the other hand urinary N, NB as % of N intake and NB as% of digested N were not affected (p>0.05) by treatments but they had a tendency to decrease compared to control. Experiment No. (3): A comparison was made between two types of feed alfalfa hay and abu 70 hay in this experiment; twelve yearling uncastrated males of Nubian goats weighing 13-17 kg were used in this experiment. The animals were randomly allocated to one of the two types of feed (alfalfa hay or Abu70) to four treatments with two water regimes with three animals per treatment following the completely randomized design with a 2x2 factorial arrangement of treatments, adlibitum Abu70 water every 24 hrs( T1), adlibitum alfalfa hay water every 24 hrs (T2), adlibitum Abu70 hay water every 48 hrs( T3), adlibitum alfalfa hay water every 48 hrs (T4). DMI, WI, WI: DMI ratio, faecal DM output, RT and RR were not affected (P>0.05) by treatments and food types whereas urine volume was significantly (P<0.05) affected by treatment, there were insignificant (P>0.05) increase of DMI, WI, urine volume in alfalfa hay compared to Abu 70 hay. Crude protein digestibility (CPD), EED, CFD, NFED and TDN are significantly (P<0.05) affected by both water restriction and feed type, whereas digestibility was improved with water restriction. Ruminal pH and ruminal NH3-N was affected significantly (P<0.05) by feed type and treatments, whereas BUN was highly (P<0.01) significantly affected by feed type and treatments. N-intake and urinary N were affected significantly (P<0.05) by feed type they were increased with alfalfa hay more than Abu70 hay but not affected by treatments, faecal-N was not XVIII affected by feed type nor by treatments, N-balance was affected (P<0.05) by feed type that it was increased by alfalfa more than Abu 70 but was not affected (P>0.05) by treatments, NB as % of intake was significantly (P<0.05) affected by feed type that it was higher in Abu 70 more than alfalfa, but was not affected by treatments. NB as % of digested was highly (P<0.01) significantly affected by feed type and treatments. Experiment No (4): A digestibility nitrogen balance experiment was conducted with six yearling uncastrated males of Nubian goats weighing 13 to 15 kg were used in this experiment, they were randomly allocated to one of the three nutritional treatments with two animals per treatment in a 3x3 Latin square design, the treatments were adlibitum water and feed (control) (T1), water restricted to 33.3% from adlibitum and feed adlibitum( T2), and water adlibitum and feed was restricted to 33.3% from adlibitum (T3). The animals were interchanged between the treatments so that the six animals were employed in each treatment. The animals were provided with alfalfa hay all over the experiment DMI decreased (P<0.05) significantly with feed restriction compared to water restriction and control whereas water intake decreased (P<0.05) significantly with water restriction compare to feed restriction and control, faecal DM output and RT were not affected (P>0.05) by treatment. On the other hand urine volume was highly significantly (P<0.01) affected by treatments it was decreased by water restriction and increased by feed restriction, RR was significantly (P<0.05) decreased by both water and feed restriction. DMD, OMD, CPD, EED, CFD, NFED and TDN were affected significantly (P<0.05) by treatments whereas they were increased with water restriction and decreased with feed restriction. Ruminal NH3-N was affected significantly (P<0.05) by treatments they increased with water restriction and showed tendency to XIX increase with feed restriction compare to control. BUN was highly (P<0.01) significantly affected by treatments, it was increased with water restriction and decreased with feed restriction compare to control. N-intake was decreased (P<0.05) significantly with water restriction and feed restriction compared to control, faecal-N was not affected by treatments, N-balance was affected (P<0.05) by feed restriction that it was decreased with feed restriction but not affected by water restriction.