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Artificial insemination (AI) can undoubtedly be regarded as the oldest and most widely used assisted reproductive technique/technology (ART) applied in livestock production and it is one of the most important ARTs. The three cornerstones of its application are that it is simple, economical and successful. Artificial insemination offers many well-known benefits for producers. Fresh, fresh + diluted + chilled and frozen semen can be used for AI in small ruminants. To ensure its successful use, the AI technique must be selected on the basis of the type of semen planned to be used. This review paper gives a detailed overview of semen processing and its effects on semen quality, as well as of the AI techniques applied in small ruminants and their success rates.

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We evaluated the lactation performance, liver lipid content and plasma metabolites indicating the energy balance of dairy cows supplemented with conjugated linoleic acid (CLA) pre- and post-partum (PP) vs. only PP. A total of 60 cows were divided into three groups (n = 20). Daily diet of cows was supplemented with 14 g of CLA (7 g cis-9, trans-11 and 7 g trans-10, cis-12 isomers) from week 3 before the expected date of calving (group CLA1), or from the day of calving (group CLA2) until 77-91 days PP. Control cows were fed an isocaloric, isonitrogenous and isolipidic diet without CLA. Between week 3 and week 6 PP, the milk yield of cows in both CLA-treated groups was approximately 4.5 kg higher (p < 0.05) than in control. Milk fat concentrations decreased from week 3 and were lower in both CLA groups than in control (p < 0.01). Body condition score loss was lower (p < 0.05) in the CLA1 than in the control group on week 5 PP. By week 11 PP, the body condition of both CLA1 and CLA2 groups exceeded that of control. Plasma non-esterified fatty acid was lower in CLA1 compared to CLA2 and control during the early PP period (p < 0.05), while this difference faded away by the late PP period. Beta-hydroxybutyrate (BHBA) increased rapidly in all groups following calving. In CLA1 group, it began to decrease sooner than in CLA2 and control. The prevalence of subclinical ketosis (BHBA > 1.2 mm) was lower in CLA1 group than in CLA2 and control (p < 0.05). Liver biopsy analyses showed that CLA1 treatment decreased (p < 0.05) the total lipid content of liver compared to control at week 5 after calving. Our results show that CLA supplementation is more efficient in alleviating body mass mobilization and decreasing the incidence of subclinical ketosis when applied as early as 3 weeks before calving than started feeding after calving.

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