Relative abilities of young sheep and goats to self-medicate with tannin-rich sainfoin when infected with gastrointestinal nematodes

Abstract

Plant secondary metabolites (PSM) are one of the promising options to control gastrointestinal nematodes in sheep and goats. The objective of this study was to assess the abilities of sheep and goats to self-medicate with tannin-rich sainfoin (Onobrychis viciifolia) (SF) when infected with gastrointestinal nematodes, using a cafeteria and an operant conditioning trial. Hypotheses were that parasitized (P) lambs and goat kids would show greater intake and preference for SF than their non-parasitized (NP) counterparts, that kids would eat more SF than lambs (due to their lower resistance against parasites and their greater ability to consume PSM), and that SF intake would increase over time for P animals. We used 20 female kids and 20 ewe lambs aged 3 months. Half of the animals per species (n = 10) were experimentally infected with 170 L3 larvae of Haemonchus contortus/kg of BW (P). The other half were free from parasites throughout the study (NP). Five weeks after infection, animals were exposed to a 24-day cafeteria trial (three 8-day periods) offering a free choice between two legume pellets: SF (3.8% condensed tannins) and alfalfa (ALF, Medicago sativa; no tannin). Subsequently, animals were involved in an operant conditioning trial of two 4-day long sessions, to assess in short-term tests their motivation to walk for a SF reward when offered in choice with freely available ALF. In the cafeteria trial, SF preference was greater in kids than in lambs, particularly in the first two periods. We did not observe a greater preference for SF in P animals, which was even greater in NP animals for periods 1 and 2. Sainfoin intake increased through periods for P animals, which led to similar SF preferences for all groups during period 3. In the operant-conditioning trial, motivation to get the SF reward was similar between P and NP animals. These results support the hypotheses that goats are more willing to consume tanniferous feeds than sheep, and that P animals increased SF intake through time. However, the emergence of a curative self-medicative behaviour was not supported, as P individuals did not show greater SF intake, preference, nor a greater motivation to get SF than NP animals, regardless of animal species. These findings are discussed with previous results and some explanations are presented.

Nemabiome metabarcoding reveals differences between gastrointestinal nematode species infecting co-grazed sheep and goats

“…During the first phase (three months prior to Day 0) the pasture was grazed by sheep and goats, including the study animals, to allow for natural L3 contamination with a representative GIN species composition; FECs and the nemabiome on Day 0 would reflect this challenge. The sheep and goats were treated with an anthelmintic drug on Day 0, so that the second phase (Day 15 to Day 30) would show the progression of intensity of re-infection with different GIN species (Gaudin et al, 2019). However, this description was not possible due to the poor efficacy of monepantel in some groups, hence FECs between Day 15 and Day 30, and the nemabiomes on Days 15 and 18 were used to describe responses to drug treatment.…”

Observación visual de rumiantes mediante el método de categorías de bocados para estimar su consumo voluntario bajo pastoreo de agostaderos

“…Por ejemplo, durante la época de sequía, las vainas de Vachellia pennatula aportan casi el 50% de la ingesta total de las ovejas que pastorean en la selva baja caducifolia, por lo que en dicho ecosistema es un recurso clave para la alimentación de los ovinos. También, con este método es posible identificar la automedicación o zoofarmacognosia, fenómeno reportado consistentemente en rumiantes que pueden expresar su conducta de selección (Hutchings et al, 2003, Gaudin et al, 2019. En dicho fenómeno, el animal mediante su conducta de ingestión incluye elementos que contribuyen a recuperar (automedicación curativa) o mantener (automedicación preventiva) su homeostasis (Amit et al, 2013;Villalba et al, 2014;2016); por ejemplo, Novelo-Chí et al (2019) utilizó el método de observación de las categorías de bocados, en cabras criollas sanas (sin anemia) pero con infección moderada de 500 huevos por gramo de heces (HPG) de nemátodos gastrointestinales al inicio de la época de lluvias.…”

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

“…In several experiments, the consumption of tanniferous forages was associated with reduced levels of GIN parasites and improved animal performance [65], even when the tannin-rich forages are given as hays or silages [37]. Many studies focused on the AH effects of tannin-rich plants and forages in small ruminants have been published in recent years [1,18,54,[66][67][68]. Among these studies, there are interesting findings: a decrease in the establishment of third-stage nematode larvae (L3) or a reduction in worm fertility and egg output in naturally infected goats consuming a moderate concentration of tanninrich plants [47,69], and a significant and prolonged reduction in nematode egg excretion in naturally infected indoor goats due to a short-term distribution of tannin-rich plants hay [70].…”