Sheep and Goats Respond Differently to Feeding Strategies Directed to Improve the Fatty Acid Profile of Milk Fat

Abstract

This bibliographic review presents and discusses the nutritional strategies able to increase the concentration of beneficial fatty acids (FA) in sheep and goat milk, and dairy products, with a particular focus on the polyunsaturated FA (PUFA), and highlights differences between the two species. In fact, by adopting appropriate feeding strategies, it is possible to markedly vary the concentration of fat in milk and improve its FA composition. These strategies are based mostly on the utilization of herbage rich in PUFA, or on the inclusion of vegetable, marine, or essential oils in the diet of lactating animals. Sheep respond more effectively than goats to the utilization of fresh herbage and to nutritional approaches that improve the milk concentration of c9,t11-conjugated linoleic acid (c9,t11-CLA) and α-linolenic acid. Dietary polyphenols can influence milk FA profile, reducing or inhibiting the activity and growth of some strains of rumen microbes involved in the biohydrogenation of PUFA. Although the effectiveness of plant secondary compounds in improving milk FA composition is still controversial, an overall positive effect has been observed on the concentration of PUFA and RA, without marked differences between sheep and goats. On the other hand, the positive effect of dietary polyphenols on the oxidative stability of milk fat appears to be more consistent.

Effect of Soybean Oil Supplementation on Milk Production, Digestibility, and Metabolism in Dairy Goats under Thermoneutral and Heat Stress Conditions

“…The SBO supplementation dramatically increased CLA content in milk of dairy goats ( Table 3 ) because of the increment in trans -vaccenic acid (TVA). This result is similar to what previously reported in dairy goats [ 14 , 15 , 16 , 17 ] and ewes [ 16 , 32 ]. The effect of SBO on TVA and CLA contents was similar in TN and HS conditions (+650 and +395% increments in TVA and CLA concentrations, respectively, on average).…”

“…Supplementation of dairy goats with soybean oil (SBO) alone [ 14 , 15 , 16 ] or mixed with fish oil [ 17 ] results in increased fat content and conjugated linoleic acid (CLA) in milk. Feeding SBO additionally improves yields of milk and protein in dairy goats when the forage:concentrate ratio in the diet is 63:37 [ 15 ].…”

Functional Odd- and Branched-Chain Fatty Acid in Sheep and Goat Milk and Cheeses

“…This FA has been received particular attention due to the important beneficial healthy effects shown in vitro, animal and human as well [50,51]. The higher concentration in sheep milk (and cheese) compared to that of goat has previously been reported [45]. Figure 3a, circle identifies goat cheese, triangle identifies sheep cheese; green symbols identified cheese produced in winter early spring, red symbols identified cheese produced in early spring-summer.…”

“…This FA has been received particular attention due to the important beneficial healthy effects shown in vitro, animal and human as well [50,51]. The higher concentration in sheep milk (and cheese) compared to that of goat has previously been reported [45].…”

“…It is noteworthy that the goat's milk processed into cheese in this Mediterranean area comes from animals raised in extensive system, characterized by natural pastures rich also in shrubs and essences of the Mediterranean maquis, which contains tannins. These different pasture conditions among species could be a possible explanation of the different concentrations in OBCFA observed between sheep and goats [45].…”