Alimentary diversity in early life and food neophobia in sheep

CATANESE, F.; VILLALBA, J.J.; DISTEL, R.A.

Mar del PLata

Congreso; 34º Congreso Argentino de Producción Animal- 1st Joint Meeting ASAS-AAPA; 2011

Asociación Argentina de Producción Animal

Ruminants show a reduced intake of feeds that were not previously experienced (neophobia), which have a negative effect on productive systems where the offer of novel feeds is common. The hypothesis of the present work was that sheep early exposed to a diverse alimentary environment will show reduced neophobic responses later in life, when compared to animals exposed to a monotonous alimentary environment. The objective was to compare changes in intake of novel feeds and flavors, and productive performance between lambs exposed in early life either to diverse or monotonous alimentary environment. Twenty, two-month-old lambs (29.1 ± 4.0 Kg, mean ± 1s.d.) were randomly assigned to two treatments: Diversity or Monotony. Lambs in Diversity were exposed during 45 days to nine combinations of two out of three feeds low in protein: energy ratio (milo: grape pomace mixture [60:40], oat grain, or beet pulp) and two out of three feeds high in protein: energy ratio (soybean meal, corn gluten meal, or alfalfa pellets). Each feed combination was assigned at random to each lamb for five days until all the combinations were exhausted. At the same time, lambs in Monotony were fed a single diet, balanced according to requirements and composed by a mixture of all feeds fed to Diversity. Following this period, all lambs were fed for 15 days with alfalfa pellets only, which was taken as a washout period previous to evaluation. After the washout period, we evaluated intake of wheat bran flavored with maple, bitter or garlic (2% w/w) for three days each. Then, we measured intake of novel feeds offered in pairs (corn distillers’ grains vs. fescue hay, rolled oats vs. green peas, and calf manna vs. rice) for five days each. Flavored wheat bran and novel feeds were offered in individual bunks from 0900 to 0915 h; and after that, lambs were fed with alfalfa pellets (2% BW) from 1500 to 1600 h. Between trials, lambs were fed for five days with alfalfa pellets only, which was taken as a washout period. The entire testing period had a length of 49 days. Data were analyzed using a repeated measures design which was run using the MIXED procedure of SAS (SAS Inst., Inc. Cary, NC; Version 9.1 for Windows). Daily intake was the repeated measure and lambs the random effect of the model. Lambs in Diversity showed higher (p<0.05) intake of wheat bran flavored with maple (7.6 vs. 5.8 ± 0.5 g/kgBW), bitter (8.1 vs. 5.8 ± 0.5 g/kgBW), and garlic (7.8 vs. 5.3 ± 0.5 g/kgBW) than lambs in Monotony (mean ± 1s.e.m., respectively). Lambs in Diversity also showed higher intake of fescue hay (1.6 vs. 0.9 ± 0.04 g/kgBW, p<0.05) when offered simultaneously with corn distillers’ grain, higher intake of green peas (8.7 vs. 4.4 ± 0.26 g/kgBW, p<0.05) when offered simultaneously with rolled oats, and higher intake of rice (13.7 vs. 10.6 ± 0.20 g/kgBW, p<0.05) when offered simultaneously with calf manna, than lambs in Monotony (mean ± 1s.e.m., respectively). During trials involving novel flavors and feeds, average daily weight gain was higher for lambs in Diversity than for lambs in Monotony (170.8 vs. 132.7 ± 12.6 g/day, respectively, mean ± 1e.e.m.; p<0.05). Our results are consistent with the hypothesis that early experience with alimentary diversity reduces neophobic responses in lambs, and has relevance in those cases where young animals are weaned early in life, raised with unique diets or single-species pastures, and then introduced to productive systems that require fast acceptance of novel feeds or diets.