Great Lakes Dairy Sheep Symposium - the Department of Animal ...
Great Lakes Dairy Sheep Symposium - the Department of Animal ... Great Lakes Dairy Sheep Symposium - the Department of Animal ...
CLA. Examination of physiological factors has established that milk fat content of cis-9, trans- 11 CLA has little or no relation to milk or milk fat yield, parity, stage of lactation or breed (Lock and Bauman, 2004). This variation must therefore, in large part, be related to individual differences in rumen output of vaccenic acid and to a lesser extent cis-9, trans-11 CLA, and to the amount and activity of Δ 9 -desaturase. Undoubtedly, the variation in Δ 9 -desaturase among individuals has a genetic basis, and there is currently interest in understanding the genetic variation and heritability of this enzyme. Increasing the activity of Δ 9 -desaturase via selection and/or nutritional manipulation offer further potential to enhance the level of cis-9, trans-11 CLA in milk through increasing endogenous synthesis (Figure 3). Increasing Δ 9 -desaturase activity would not only impact on the level of cis-9, trans-11 CLA in milk fat, but would also increase other unsaturated fatty acids that are products of this enzyme. Finally, the final concentration of cis-9, trans-11 CLA in dairy products is, in large part, related to the cis-9, trans- 11 CLA concentration in the raw milk fat and the fat content of the final product. Any changes in the cis-9, trans-11 CLA content related to processing or to storage of dairy products are minimal when compared to the variations associated with diet formulations and differences among individual animals. We have used such feeding regimes and taken advantage of individual animal variation to produce cis-9, trans-11 CLA-enriched butter for use in biomedical studies with animal models. In a series of studies, we have shown that dietary consumption of cis-9, trans-11 CLA-enriched butter is effective in reducing the progression and incidence of tumors in a rat-model of mammary cancer. These results are among the first to demonstrate that a naturally produced anticarcinogen, consumed as a component of a natural food, is effective in reducing cancer. Furthermore, vaccenic acid present in milk fat is also anticarcinogenic via its conversion to cis-9, trans-11 CLA by our own Δ 9 -desaturase enzyme system. Recently, we have shown that naturallyderived cis-9, trans-11 CLA also has potent antiatherogenic properties. See the review by Bauman et al. (2005a) for a detailed discussion of the biological effects of cis-9, trans-11 CLA and vaccenic acid. The increased interest in the effect of bioactive fatty acids in milk fat has led to a number of recent studies reporting the effects of different diets on the fatty acid composition of sheep milk. An example of typical sheep milk fatty acid profile is shown in Table 3 and is taken from our study reported earlier when ewes received the unsupplemented (Control) diet. In general, the unsupplemented ewes had a milk fat content and fatty acid profile similar to other studies with lactating sheep (Rotunno et al., 1998; Sevi et al., 2002). The content of cis-9, trans-11 in ewes fed the control diet was however, lower than that reported in a survey of ewes when grazing grass (Nudda et al., 2005), but comparable to values when a dried complete diet was fed (Luna et al., 2005). A recent review examined the effect of forage species and stage of growth on the cis- 9, trans-11 CLA content of sheep milk fat under Mediterranean conditions (Cabiddu et al., 2005). As for dairy cows, feeding fresh lush pasture results in the highest cis-9, trans-11 CLA content of milk fat. Similarly, seasonal changes in the cis-9, trans-11 CLA content of sheep milk have been reported which were related to pasture quality and availability (Figure 6; Nudda et al., 2005). Finally, it has also recently been reported that the fatty acid composition of dairy products (ripened cheeses and ricotta) produced from CLA-enriched milk were dependent on the fatty acid composition of the starting raw milk, with manufacturing, ripening and storage having little or no effect on the cis-9, trans-11 CLA content of the final product (Addis et al., 2005; 78
Luna et al., 2005; Nudda et al., 2005). As shown in Table 4 there was little or no change in the content of important fatty acid in chesses over a four-month period. In general, it is apparent that nutritional strategies to alter the fatty acid composition of sheep milk fat are similar to those that have been examined in dairy cows. Table 3. Typical fatty acid profile of sheep milk fat. Fatty acid g/100 g Fatty acid g/100 g 4:0 4.2 18:1 trans-10 0.7 6:0 1.9 18:1 trans-11 1.7 8:0 1.4 18:1 trans-12 0.3 10:0 3.5 18:1 cis-9 23.6 12:0 2.1 18:2 cis-9, cis-12 6.8 14:0 6.8 18:2 cis-9, trans-11 0.8 14:1 cis-9 0.5 18:2 trans-10, cis-12 trace 15:0 0.7 18:3 cis-9, cis-12, cis-15 0.2 16:0 31.1 20:0 0.2 16:1 cis-9 0.9 Other 2.1 17:0 0.3 Summation 18:0 9.4 C16 47.6 Figure 6. Seasonal changes in the cis-9, trans-11 CLA content in sheep milk, cheese, and ricotta sampled every 2 wk from March to June in 2 milk processing plants in North Sardinia (Nudda et al., 2005). Different letters indicate significant differences (P < 0.05) between the sampling periods. cis-9, trans-11 CLA (mg/100 mg fatty acids) 79
- Page 37 and 38: REARING LAMBS AT 3-CORNER FIELD FAR
- Page 39 and 40: PROFITABILITY OF SMALL RUMINANT FAR
- Page 41 and 42: Table I. General Farm Description L
- Page 43 and 44: Table 4. Business Balance Sheet Ass
- Page 45 and 46: Table 5. Income Statement Income Av
- Page 47 and 48: Lifestyle is a definite reason for
- Page 49 and 50: Grossman et al., 1999). Animals wit
- Page 51 and 52: Physiological Factors Affecting Lac
- Page 53 and 54: Recently, it has been hypothesized
- Page 55 and 56: (co)variate in the genetic model us
- Page 57 and 58: show that milk production increases
- Page 59 and 60: Figure 6 - Lactation curves of ewes
- Page 61 and 62: milk yield (g/d) 3000 2500 2000 150
- Page 63 and 64: a genetic potential to produce more
- Page 65 and 66: when compared with the control grou
- Page 67 and 68: probability (%) 70 60 50 40 30 20 1
- Page 69 and 70: considered “healthy” if every S
- Page 71 and 72: Finally, udder health has to be con
- Page 73 and 74: De Maria Ghionna C., Dell’Aquila.
- Page 75 and 76: Manalu, W., Sumaryadi, M.Y., Sudjat
- Page 77 and 78: Rupp R., Boichard D., Barbat A., As
- Page 79 and 80: Introduction MILK FAT SYNTHESIS AND
- Page 81 and 82: The variety of fatty acids allows t
- Page 83 and 84: Germany); we have shown previously
- Page 85 and 86: Manipulating Milk Fatty Acid Compos
- Page 87: increase in rumen output of vacceni
- Page 91 and 92: Cabiddu, A., M. Decandia, M. Addis,
- Page 93 and 94: MANAGING YOUR OWN RETAIL SHOP: MARK
- Page 95 and 96: The Reality our feta demonstrates t
- Page 97 and 98: Meat and meat dishes: 1. Legs: whol
- Page 99 and 100: 5. We have daily visits from chefs
- Page 101 and 102: HOW TO GRAZE DAIRY SHEEP AND SUPPLE
- Page 103 and 104: significantly increase milk product
- Page 105 and 106: All parameters are significantly di
- Page 107 and 108: Table 6 - Dry matter intake and mil
- Page 109 and 110: animals can reduce intake, as they
- Page 111 and 112: Milk fat and protein concentrations
- Page 113 and 114: fat concentration can be used as a
- Page 115 and 116: (1998), working with adult Sarda ew
- Page 117 and 118: equirements. The relationship found
- Page 119 and 120: that there have not been enough stu
- Page 121 and 122: Grazing methods Grazing methods are
- Page 123 and 124: How should the number of paddocks b
- Page 125 and 126: Table 16 - Description of four past
- Page 127 and 128: a) concentrates supplied during mil
- Page 129 and 130: References Arnold G.W., and Dudzins
- Page 131 and 132: supplemented with corn grain. Optio
- Page 133 and 134: succeeding add on pastures smaller
- Page 135 and 136: diverse forage have much to do with
- Page 137 and 138: dairy farming. In fact, Vermont agr
Luna et al., 2005; Nudda et al., 2005). As shown in Table 4 <strong>the</strong>re was little or no change in <strong>the</strong><br />
content <strong>of</strong> important fatty acid in chesses over a four-month period. In general, it is apparent that<br />
nutritional strategies to alter <strong>the</strong> fatty acid composition <strong>of</strong> sheep milk fat are similar to those that<br />
have been examined in dairy cows.<br />
Table 3. Typical fatty acid pr<strong>of</strong>ile <strong>of</strong> sheep milk fat.<br />
Fatty acid g/100 g Fatty acid g/100 g<br />
4:0 4.2 18:1 trans-10 0.7<br />
6:0 1.9 18:1 trans-11 1.7<br />
8:0 1.4 18:1 trans-12 0.3<br />
10:0 3.5 18:1 cis-9 23.6<br />
12:0 2.1 18:2 cis-9, cis-12 6.8<br />
14:0 6.8 18:2 cis-9, trans-11<br />
0.8<br />
14:1 cis-9 0.5 18:2 trans-10, cis-12<br />
trace<br />
15:0 0.7 18:3 cis-9, cis-12, cis-15 0.2<br />
16:0 31.1 20:0 0.2<br />
16:1 cis-9 0.9 O<strong>the</strong>r 2.1<br />
17:0 0.3 Summation<br />
18:0 9.4 C16 47.6<br />
Figure 6. Seasonal changes in <strong>the</strong> cis-9, trans-11 CLA content in sheep milk, cheese, and ricotta<br />
sampled every 2 wk from March to June in 2 milk processing plants in North Sardinia (Nudda et<br />
al., 2005). Different letters indicate significant differences (P < 0.05) between <strong>the</strong> sampling periods.<br />
cis-9, trans-11 CLA<br />
(mg/100 mg fatty acids)<br />
79
Change language