Concerns about global warming and greenhouse gases have increased the interest of governments and the public sector to find solutions. To reduce the effects of global warming caused by greenhouse gases, especially methane, it is necessary to change animal production systems and adopt new strategic approaches. The reduction of enteric methane in livestock is a long-standing problem regarding the energy efficiency of consumed feed. In this review, the sources of production, dissemination, and introduction of accepted scientific and practical solutions in order to reduce methane gas in breeding and production units of dairy cows have been investigated. To carry out this research, a thorough search was conducted in articles published in valid databases between 1967 and 2022. A total of 213 articles were reviewed, and after screening, 159 were included in the study and analyzed using a PRISMA flow diagram. In general, low livestock efficiency, low-quality feed, a shortage of knowledge, and inadequate investment are the main causes of emission of these gases in poor or developing countries. On the other hand, developing countries may not always have access to the same methods that are utilized in industrialized countries to minimize the production of methane and other greenhouse gases like nitrous oxide. According to their conditions, developing countries should use the available tools to reduce methane production and emission, considering the costs, local knowledge, feasibility, and local laws. In future, there will be a greater need for interdisciplinary research to look for sustainable and acceptable methods for reducing methane emissions and other greenhouse gases from animal husbandry units, especially dairy cows. To change the population of rumen methanogens, as the main producers of methane, strategies such as feeding management, addition of inhibitors and vaccination are suggested. Also, there is a need for more applied research for reducing methane emissions.

The objectives of this study were to evaluate the alleviating effects of the isoquinoline alkaloid berberine (BBR) on the energy balance (EB), glucose and insulin metabolism, and liver functionality in transition dairy goats, as reflected by blood metabolites and enzymes. Twenty-four primiparous Saanen goats were randomly allocated to four groups. Goats in each group received, ad libitum, the same basal diet during the pre- and post-partum periods of evaluation. Goats received daily0, 1, 2, or 4 g BBR (coded as CON, BBR1, BBR2, and BBR4, respectively). Dry matter intake (DMI) and milk yield were recorded daily. Blood samples were collected on days −21, −14, −7, 0, 7, 14, and 21 relative to kidding, and individual body condition scores (BCSs) were also recorded. Supplementation with either BBR2 or BBR4 increased (p < 0.05) pre- and post-partum DMI, increasing (p < 0.05) the intakes of net energy for lactating and metabolizable proteins. BBR2 and BBR4 increased (p < 0.05) post-partum milk production as well as fat-corrected milk (FCM), energy-corrected milk (ECM), and feed efficiency, indicating the alleviating effect of BBR on the negative energy balance (NEB) in transition goats. The daily ingestion of either 2 or 4 g BBR reduced (p < 0.05) plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) and increased (p < 0.05) the dynamic change in the liver activity index (LAI) and liver functionality index (LFI), implying its hepatoprotective effect on transition goats. Overall, the results suggest that BBR supplementation of at least 2 g/d may help to ameliorate insulin resistance (IR) and fat metabolism disorders initiated by the NEB in transition dairy goats.

SUMMARY The effect on performance of adding calcium (Ca)-butyrate and Oleobiotec (a flavouring agent) additives to dairy calf starter diet was investigated. Thirty-two newborn Holstein calves (16 males and 16 females) were used in a completely randomized design with four treatments as: (1) diet with no additives, (2) diet containing Ca-butyrate, (3) diet containing Oleobiotec and (4) diet containing Ca-butyrate plus Oleobiotec. Milk of calves was supplemented with additives in the first 20 days of the study and then additives were top-dressed into the starter. Calcium-butyrate had no effect on starter and alfalfa intake during pre-weaning, post-weaning and over the whole trial period but it significantly increased the average daily gain and feed efficiency of calves during post-weaning and the whole trial period. Adding Oleobiotec did not change calf performance significantly. Furthermore, no synergistic effect of experimental additives on calf performance was observed.

The objective of this study was to investigate the effect of berberine (BBR) supplementation on productivity, antioxidant markers, and the fatty acid (FA) profile in the colostrum and milk of goats. Twenty-four primiparous Saanen goats were supplemented with 0, 1, 2, and 4 g/d (per goat) of BBR in control (CON), BBR1, BBR2, and BBR4 groups (n = 6 per group), respectively, from 21 days before expected kidding to 21 days after parturition. Blood sampling was carried out at −21, −14, −7, 0, 7, 14, and 21 d relative to delivery. Colostrum was collected within the first and second milking (d 1 of lactation), and milk was harvested weekly after kidding. Both BBR2 and BBR4 increased dry matter intake (DMI) (p ≤ 0.05) and energy balance (EB) as well as colostrum and milk production. Both BBR2 and BBR4 decreased (p ≤ 0.05) plasma levels of cholesterol, haptoglobin, and ceruloplasmin, while elevating the plasma albumin and paraoxonase (p ≤ 0.05), which may indicate that BBR mitigates inflammation during the transition period. BBR reduced (p ≤ 0.05) malondialdehyde (MDA) and increased (p ≤ 0.05) total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in blood, colostrum, and milk. Concentrations of de novo fatty acid in colostrum and milk were increased (p ≤ 0.05) with both BBR2 and BBR4. Free fatty acid (FFA) concentration in colostrum and milk fat were lower (p ≤ 0.05) in BBR2 and BBR4 compared to CON. The concentration of saturated fatty acids (SFAs) in colostrum and milk fat increased (p ≤ 0.05) with BBR2 and BBR4, while unsaturated fatty acids (USFAs) decreased (p ≤ 0.05) in milk. In summary, supplementation with at least 2 g/d BBR may enhance the EB and antioxidant status of dairy goats.