Climate change is causing detrimental changes in living organisms, including pathogens. This review aimed to determine how climate change has impacted livestock system management, and consequently, what factors influenced the gastrointestinal nematodes epidemiology in small ruminants under tropical conditions. The latter is orientated to find out the possible solutions responding to climate change adverse effects. Climate factors that affect the patterns of transmission of gastrointestinal parasites of domesticated ruminants are reviewed. Climate change has modified the behavior of several animal species, including parasites. For this reason, new control methods are required for controlling parasitic infections in livestock animals. After a pertinent literature analysis, conclusions and perspectives of control are given.

During the rainy season, the tropical deciduous forest (TDF) supposedly represents an abundance of biomass for sheep and goats. Nevertheless, quantitative estimations of feed intake during the rainy season are lacking. This study investigated the feeding behaviour of sheep and goats in a TDF in Mexico and quantified their nutrient intake during the rainy season. Plant species (PS) consumed, size and weight of bites, and nutritional quality were determined by continuous bite monitoring through direct observation. Adult ewes (n = 3) and goats (n = 3) were observed in their grazing circuits (4 h/day) for 12 days during the rainy season. Sheep and goats consumed 61 PS and performed a similar median number of bites (1751 vs 2053 bites/day, respectively; P > 0.05). Although they shared 52.5% of the PS consumed, only seven PS contributed most of the dry matter intake (DMI) for sheep (96.7%) or goats (90.5%). Sheep consumed more grass than goats (79.8% vs 48.3% of their DMI, respectively), whereas goats ate more shrubs than sheep (30.0% vs 7.6% of their DMI, respectively). The diet ingested by goats included more polyphenols (P < 0.05) and a higher frequency of larger and heavier bites than sheep (P < 0.05). Sheep reached 61.3% and 57.7% of their metabolisable energy and crude protein maintenance requirements. Similarly, goats covered 63.3% of their metabolisable energy and 108.2% of crude protein requirement. Although the main ration of sheep and goats was composed of similar PS, their different feeding behaviour resulted in different macronutrient consumption.

The effect of tannin-rich fodder (TRF) consumption on the saliva response of Criollo goats without previous browsing experience was determined. Eighteen kids were allocated into three treatments (n = 6 each): control group (CG), short-term tannin stimulus (TS) and long-term tannin stimulus (TL). Three experimental periods were used: adaptation (two weeks) in which the three treatment groups were fed Pennisetum purpureum grass and supplemented with a balanced feed. In period 1 (five weeks), TS and TL treatments were fed TRF (Lysiloma latisiliquum) with 55.5 g/kg DM condensed tannins (CT), grass and balanced feed. In period 2 (three weeks), L. latisiliquum fodder was withdrawn from the TS group. Thus, both the TS and the CG kids were only offered grass and balanced feed, while TL kids continued to receive TRF. In each period, saliva samples were collected to measure the tannin–protein interaction, salivary protein and protein turbidity index (PTI). The salivary protein was similar in all treatments and periods (P > .10). The goats' saliva reacted similarly when mixed with either tannic acid or L. latisiliquum water-acetone extract. Although the PTI tended to increase in the TL group compared to CG and TS with time, such difference was not significant. Thus, TRF intake failed to further increase the salivary response or PTI. Therefore, the saliva of goats from Yucatan, without previous browsing experience do have a constitutive response as it can block tannins irrespective of TRF stimulus.