Effect of a screen with flaps and straw on behaviour, stress response, productive performance and meat quality in indoor feedlot lambs.

We analysed the effect of a modified pen using a wooden screen with flaps and cereal straw as forage and bedding, on behaviour, stress response, performance and meat quality variables of lambs housed in feedlots. Sixty male lambs were placed in enriched (ESF) or conventional (CO) pens (3 pens/treatment, 10 lambs/pen). The CO environment was barren. The ESF lambs showed a great preference for the provided items, which encouraged more natural and richer behaviour, reducing stereotypies and lamb aggressions, and increasing affiliations (P ≤ 0.05), which improves group cohesion. However, ESF lambs also developed a more natural coping style to the handling, evidenced by the higher cortisol levels (65.4 vs. 43.8 nmol/L) and a higher eye temperature as response to the reactivity test (38.1 vs. 37.8 °C). The ESF lambs had a higher (P ≤ 0.05) slaughter weight (27.2 vs. 26.3 kg), conformation score (7.38 vs. 6.07) and pH 24 (5.63 vs. 5.56) but lower cooking losses (12.9 vs. 14.9%) than CO lambs.

Periconceptional undernutrition increases quantity and quality of oocyte population, but not cognitive or emotional response of 60-day-old lambs.

Maternal periconceptional undernutrition is associated with altered development and increased risks of adverse outcomes in the offspring. The aim of this work was to determine the effect of periconceptional undernutrition on behavioural and reproductive aspects of the offspring. Fifty ewes were synchronized in oestrus (day 0) and allocated to two groups (n = 25) to be fed diets that provided 1.5 (C) or 0.5 (L) times the requirements for maintenance until day 15. Ewes were mated and fed the control diet from day 16 until lambing. Two months after lambing, 26 lambs were exposed to tests to determine their cognitive/emotional responses. Six ewe lambs were euthanized and in vitro oocyte maturation and fertilization procedures performed. The experimental diets produced no changes of mean live weight (LW) of C ewes, L ewes presenting a reduction in their initial LW with significant differences at day 15, in comparison with C ewes (p < 0.05). L ewes experienced a significant reduction in their body condition (BC) in comparison with C ewes (p < 0.05). Fourteen days after the onset of the experimental diets, mean LW and BC of L ewes was significantly lower than those of C ewes (p < 0.05). Undernourished ewes presented a trend to a reduction of prolificacy and fecundity (p < 0.10) in comparison with C ewes. Emotional and cognitive test revealed a similar response between groups. Ewe lambs from the undernourished ewes presented a population of oocytes 1.7 times higher than ovaries from control ewe lambs (66.0 ± 0.73 vs. 113.7 ± 15.6 oocytes; p < 0.05) and had more oocytes in the 'good' (p < 0.05) and 'healthy' (p < 0.05) categories. In conclusion, a low plane of nutrition around conception significantly increases quantity and quality of the oocyte population of 60-day-old female descendants. Modifications of the cognitive and emotional responses of the progeny have not been evidenced.

The effect of periconceptional undernutrition of sheep on the cognitive/emotional response and oocyte quality of offspring at 30 days of age.

Maternal periconceptional undernutrition is associated with altered development and increased risks of adverse outcomes in the offspring. This circumstance is normal in flocks under extensive farming systems, which depend on natural forage resources. The aim of this study was to determine the effect of periconceptional undernutrition in sheep on behavioral and reproductive aspects of the offspring. Eighty ewes were synchronized in estrus and allocated to two groups (n=40) to be fed diets that provided 1.5 (C) or 0.5 (L) times the requirements for maintenance. Ewes were mated and 7 days later fed the control diet until lambing. One month after lambing, 32 lambs were exposed to tests to determine their cognitive and emotional responses. Six ewe lambs were euthanized and in vitro maturation and fertilization procedures were performed. L ewes presented a significant reduction in prolificacy and fecundity (P<0.05) in comparison with C ewes. Mean LW at lambing of L lambs was significantly higher than C lambs (C: 3.80 ± 0.11; L: 4.24 ± 0.15 kg, P<0.05). Lambs born from C ewes spent more time walking than L lambs (P<0.05) in the isolation test, revealing a decrease in the locomotor activity of lambs born from undernourished ewes around conception. Ewe lambs from the undernourished ewes presented a total population of oocytes 2.3 times higher than ovaries from control ewe lambs (60.0 ± 7.8 v. 140.0 ± 18.5 oocytes; P<0.05). In conclusion, periconceptional undernutrition is able to produce an increment in the body weight and the oocyte population, and an alteration of the locomotor activity of the offspring.

Effects of an enriched housing environment on sensory aspects and fatty-acid composition of the longissimus muscle of light-weight finished lambs.

We analysed the effect of enriched housing on the sensory meat quality and fatty acid composition of longissimus muscle in 60 entire Rasa Aragonesa lambs, housed indoors for 5 weeks in six pens (10 lambs/pen, 0.95 m(2)/lamb, initial weight 17.13±0.18 kg and carcass mean 12.23±0.23 kg); three control pens (barren) and three enriched pens (straw, platform with ramps and a small ramp). The final weight, carcass weight, fatness scores and cooking losses of meat from enriched lambs (EG) were higher and pH 24 was lower (P ≤ 0.05). The EG lambs had more C18:0 and total SFA (P ≤ 0.05). Lamb odour and grass odour were more intense in EG (P ≤ 0.05). Overall liking was higher for EG (P ≤ 0.05) and associated with tenderness (P ≤ 0.0001). The results suggest that environmental enrichment can have effects on fatty acid composition and sensory meat quality.

Effect of enriched housing on welfare, production performance and meat quality in finishing lambs: the use of feeder ramps.

This study analyses the effect of environmental enrichment on the welfare, productive traits and meat quality of lambs housed in feedlots. Sixty lambs were placed in enriched (EE) or conventional (CO) pens (3 pens for each treatment, 10 lambs/pen) where EE had a wooden platform with ramps that provided access to a concentrate hopper, cereal straw as bedding and forage, and one play ramp. The CO pen was barren, similar to commercial feedlots. The physiological adaptation response of EE lambs was more efficient than CO, since the latter mobilised more body reserves (i.e., increased NEFA, P<0.05), and had lower levels of immunity (i.e., increased N/L, P<0.05), which indicate chronic stress, probably associated with the barren environment. The EE lambs had a higher (P<0.05) average daily gain, with heavier carcasses and higher fattening scores, as well as lower pHult, higher L and b values, and lower values of texture (P<0.05).