Feeding Bucks and Pet Goats
Adult male goats and wethers should in general be fed a ration similar to what is appropriate for non-pregnant, non-lactating does. The energy requirements for maintenance are probably somewhat more for males than for females of equivalent metabolic body size.
The French recommend an increase of 10% for males. An additional increase of 15% in energy and in protein and minerals is desirable beginning four to six weeks before the breeding season (Morand-Fehr and Sauvant 1978; Rankins et al. 2002). This normally needs to be supplied as grain (approximately 0.5 kg), because the buck may be so overexcited by the presence of his does that he does not take time to eat enough hay. Even with a supplement it is common for bucks to stop growing or lose weight during the breeding season (Louca et al. 1977; Gall 1981; Walkden-Brown et al. 1994). Feeding a poor-quality ration (poor hay) to bucks is associated with a decreased scrotal circumference and poorer semen motility (Arbeiter 1963; Walkden-Brown et al. 1994).Good-quality grass forage and minimal grain, when supplemented with a trace mineralized salt and abundant fresh water, should generally meet most nutritional needs of male and female goats at maintenance. Access to legumes should be limited to avoid calcium and protein excesses and nutritional bone disease (Adams 1986) as well as calcium carbonate urolithiasis in males. Because forage quality is highly variable, owners should be encouraged to record the weight or girth tape measurement of their pets once a month. Restricted feeding or energy/protein supplementation can then be prescribed before the animal becomes either obese or emaciated.
Urolithiasis
Young male kids, breeding bucks, and wethers kept as pets or for fiber production are susceptible to urinary calculi. Commonly, when high-concentrate feeding is practiced, a relative phosphorus excess predisposes to the precipitation of struvite (calcium, magnesium, and ammonium phosphates) crystals in the bladder.
Urolithiasis is discussed in detail in Chapter 12.Dietary recommendations to prevent the condition can be briefly summarized as follows. Dietary calcium : phosphorus should be at least 2 : 1 in growing animals; some authors recommend 3 or 4 : 1 (Van der Westhuysen et al. 1988). Excessive phosphorus is undesirable, even if additional calcium is incorporated into the diet to adjust the ratio. Ideally, the total ration fed to a buck or wether should not contain more than 2.5 g P/kg DM, though this level is exceeded by many roughages. Likewise, the magnesium in the diet should not exceed the requirement for proper growth or maintenance. If attention is only given to the Ca : P ratio, the total quantity of minerals to be excreted in urine often exceeds what can be kept in solution. In general, mature males should not receive dairy concentrates or large quantities of alfalfa or subterranean clover, because these feeds contain excessive calcium and protein. Calcium carbonate stones are a common problem in mature wethers (Nwaokorie et al. 2015), and a Ca : P ratio of 1 : 1 may be more appropriate for these goats, although this warrants further investigation. Good-quality grass hay is ideal for bucks.
French recommendations specify that the quantity of grain fed to a buck should not exceed 500 g/day (Morand- Fehr and Sauvant 1988). Feeding more roughage and avoiding pelleted feeds may also help to maintain a fiber mat in the rumen and increase fecal (as opposed to urinary) output of phosphorus (NRC 2007). Ammonium chloride may be added at 0.5-1% of the ration or 2% of the concentrate to acidify urine and thus discourage pre - cipitation of struvite, although pulsatile administration of ammonium chloride will probably be more effective. Clean water should be available at all times. Salt can be added to the ration at 4-5% to increase water intake and diuresis.
Posthitis
If excessive dietary protein is fed to a male goat, especially a castrated animal, the quantity of urea in the urine is increased.
Urea-splitting corynebacteria within the prepuce can then release free ammonia, which scalds the external skin and preputial mucosa and produces “pizzle rot,” described in Chapters 12 and 13.Arthritis
Diets containing excessive calcium have been associated with calcification of periarticular tissues, ankylosis, and a stiff gait (Guss 1977), although experimental reproduction of the syndrome in goats is lacking. The pathogenesis is considered to be hypercalcitoninism, induced in nonlactating animals (such as heifers and breeding bulls; Rostkowski et al. 1981) by dietary calcium levels appropriate for lactating animals. Published descriptions of the syndrome in goats mostly predate discovery of the CAE virus; it is also possible that excess calcium speeds dystrophic calcification of periarticular tissues damaged by the CAE virus, as discussed in Chapter 4. To avoid both metabolic bone disease and exacerbation of CAE in bucks and nonlactating pet goats, dietary calcium should be limited to 1.5% of the diet DM; the daily calcium requirement for mature animals weighing 70 kg is approximately 2.6 g (NRC 2007).