Special Considerations in Feeding Angora and Cashmere Goats
When Angoras are selected for high mohair production, their resulting higher nutrient requirements leave them only marginally capable of meeting their needs under normal foraging conditions in the dry climates to which they are best adapted (Huston 1981).
Supplemental protein and energy are typically needed for early growth, at breeding, during mid and late gestation, and after parturition. Supplemental feeding and shelter are also important for prevention of “freeze loss” after shearing, as discussed in Chapter 2.Mohair Production
To allow for growth of the fleece (1.8-6 kg/year; Di Trana and Sepe 2008), Angora goats should be fed additional nutrients above those specified for maintenance, activity, gestation, and lactation of other breeds. The NRC (1981b) recommended a daily energy supplement of 30 kcal of ME (which could be approximated by 0.72? 30 = 21.6 kcal NEl) per kg of annual fleece. The protein supplement for the same kg of fleece (calculated from a protein-to-energy ratio) is 4.3 g TP or 3 g DP. More recently, regression equations have been developed to try to predict the requirements of Angora goats for energy and protein (Luo et al. 2004b), but do little to help an owner with diet formulation. However, ration calculators are available online to convert the formulas into a diet for the goats (Gipson et al. n.d.).
Increased sulfur in the diet is also necessary (Adams 1986; Bretzlaff 1990; Qi et al. 1994). Feeding inorganic sulfur is beneficial as long as the rumen microbes are supplied with adequate nitrogen and energy to synthesize sulfur- containing amino acids, especially methionine and cystine, which are required for keratin production. Feeding of rumen bypass proteins high in sulfur-containing amino acids such as rapeseed and fish meal has also been proposed (de Simiane 1990). Supplementing yearling Angoras averaging 47.5 kg bw with 2.5 g/day of a commercial rumen-protected methionine product increased mohair production by 46% (Galbraith 2000).
However, feeding of zinc methionine to supply a rumen bypass form of this important amino acid had minimal effects on mohair production (Puchala et al. 1999).It has been estimated that mature females require 9%, 10%, and 11% crude protein when they are, respectively, non-pregnant, late pregnant, and lactating. Except during dry years and in winter, the range diet is adequate. At times of increased need and decreased availability, a supplement of 40% cottonseed meal and 60% sorghum grain (24% crude protein and 3.25 Mcal digestible energy/kg) has proven adequate (Huston 1981). To avoid indigestion and metabolic diseases, the proportion of grain in late gestation should be limited to 40% of DM (0.3-0.4 kg for a 35 kg doe). During lactation, the proportion of concentrates (DM basis) in the total ration should never exceed 60% (de Simiane 1990).
A reduced fiber diameter enhances the commercial value of mohair and cashmere. It is often noted that the diameter of the mohair fiber increases slightly with better nutrition. Thus, in one study of yearling males, the fiber diameter for a ration protein of 12% was 36 μm, while for a ration protein of 18%, fiber diameter was 38 μm (Huston et al. 1971). In this same study, clean fleece weight increased from 6.5 to 9.9 pounds and pounds of feed per pound of mohair decreased from 84 to 61 with the higher protein. A later study showed that yearlings produced 31% more mohair when fed 16% protein compared with an 8% protein diet (Jia et al. 1995). In another study using mature wethers, increasing the dietary CP level from 10 to 19% (DM basis) resulted in an 83% increase in live weight gain and a 38% increase in mohair produced over a 112-day feeding period (Calhoun et al. 1983). Intentionally depriving the Angora goat of protein is thus a false economy, and causes negative effects on health, reproduction, feed conversion, and mohair yield. Increasing the stocking rate of mature Angoras on pasture can decrease fiber diameter by 4 μm via a decrease in bw.
Regression analysis showed that fiber diameter decreased by 0.4 μm for each kg fasted live weight lost (McGregor 1986). Nutrition has minimal if any effects on the medullation of mohair (Lupton et al. 1991). McGregor (2018) reports that Angoras with higher bw have more medullated fibers, but that this effect is not driven by bw change during shearing periods.Reproductive performance is improved when does have a higher bw at breeding (Snyman 2010). When does are in poor body condition, flushing (feeding increased energy) at the beginning of the breeding season can markedly increase the number of kids produced, and the best-quality mohair is obtained from young animals. When grazing is poor, feeding a markedly increased energy provision to Angora does before mating increases the kidding percentage by 20-25%. This can be achieved by feeding 500 g of “chocolate grain” (whole grain treated with alkali-ionophore; see discussion of feeding the pregnant doe to prevent abortion) per day per doe from two weeks before to two weeks after introduction of the buck (Van der Westhuysen et al. 1988). Wheat treated with 2% slaked lime has been used in a similar fashion in Australia (McGregor 1998). Other flushing recommendations include feeding 250-500 g of corn/day or moving to fresh pasture (Bretzlaff et al. 1991b).
Another management practice that affects both the nutritional status and the reproductive efficiency of Angoras is the selection for open faces. Hair-blind animals on range cannot forage selectively or reproduce well (Shelton 1961; Van Tonder 1975). However, length of facial hair is positively correlated to length of the fleece overall, and trimming the hair on the head to expose the eyes (“wigging”) three months after each body shearing is currently preferred to genetic selection for an open face.
Vitamin and mineral requirements for Angoras should be similar to those for other goats. Phosphorus is sometimes deficient in range forage, and mineral supplements offered should not have a calcium : phosphorus ratio more than 2 : 1 (Huston et al.
1971).Angora Kid Growth
The growth rate required of Angora kids is less than what many producers desire for dairy kids. This is because the Angora typically is not bred until 18 months of age, when it should weigh 25 kg. Adult females are expected to weigh 30-60 kg. It has been estimated that kids should weigh 15 kg by weaning and 20 kg by April 1 in the United States.
A supplement is imperative to achieve even this moderate gain on winter range in Texas. Without supplementation, severe stunting is likely to occur after weaning, which will impair the reproductive performance of the young doe.
Cashmere Production
Cashmere fiber, a fine, downy fiber produced as an undercoat (see Chapter 2), is produced seasonally and in far smaller quantities per goat than is mohair. Annual production is often 300 g/head or less, and the requirements for amino acids are more easily met on a daily basis (Galbraith 2000). Increasing the dietary protein or providing sulfur-containing amino acids above the requirements for maintenance and fleece production does not improve the quantity or quality of cashmere produced (Jia et al. 1995; Di Trana and Sepe 2008) and may cause an undesirable increase in fiber diameter. Likewise, feeding increased amounts of energy or decreasing the stocking rate does not increase cashmere production, although bw and guard hair growth are increased (Russel 1992). McGregor (1998) has pointed out, however, that goats with a good genetic potential for fiber production produce more cashmere if they gain weight over summer and fall, with a total weight gain of 1-2 kg being desirable on an economic basis. Heavier animals produce more cashmere, but as cashmere production increases, the fiber diameter increases. Wethers over 55 kg should be culled because of the lower price paid for coarse fiber (McGregor 1998). It is important to meet maintenance and growth requirements, which are similar to those of other breeds, for young goats during the anagen phase of fiber growth.