Effects of weaning age on growth, nutrient digestibility and metabolism, and serum parameters in Hu lambs

Abstract

This study was conducted to investigate the effect of weaning age on growth performance, nutrient digestion and metabolism, and serological indicators, and to obtain an optimal weaning age in Hu lambs. Forty-eight newborn Hu lambs (birth weight, 2.53 ± 0.14 kg) were randomly divided into 4 groups. The lambs in control group (ER) suckled their dams. The lambs in other three experimental groups were weaned on milk replacer at 10, 20, and 30 days of age (EW10, EW20, and EW30 groups), respectively. The results were as follows: 1) lambs in EW10 and EW30 groups had a lower (P < 0.05) ADG than those in ER group within 10 days post-weaning; the weaned lambs began to show a higher (P < 0.05) ADG than those in ER group after 20 days post-weaning. 2) EW10 and EW20 groups had a higher (P < 0.05) creep feed intake than EW30 and ER groups from 15 to 60 days of age. 3) The apparent digestibility of dry matter, organic matter, gross energy, nitrogen, ether extract and phosphorus, and the deposition of nitrogen and phosphorus did not differ (P > 0.05) among groups; however, the apparent digestibility and deposition of calcium in early weaned lambs were lower (P < 0.05) than those in ewe-reared lambs. 4) The albumin content in EW30 group was lower (P < 0.05) than that in ER group; the globulin content in EW30 group was higher (P < 0.05) than that in other groups; the content of serum insulin-like growth factor-Ⅰ in weaned lambs tended to increase compared with lambs in ER group. Finally, the growth rate of lambs decreased within 10 days post-weaning, but early weaning boosted creep feed intake, leading to better growth and health later in life. The Hu lambs can be weaned on milk replacer and creep feed at 10 days of age.

Comparative Effects of Stovers of Four Varieties of Common Vetch on Growth Performance, Ruminal Fermentation, and Nutrient Digestibility of Growing Lambs

“…The ADG of Hu lambs aged about 90 days varied from 200.00 to 251.60 g/day, and these values were similar to those previously reported by Chai et al [27]. The greater ADG of lambs offered control, CLJ1, and CLJ2 diets resulted in a greater FCR compared to other diets, despite the DMI not differing among treatments.…”

Dynamics of biochemical parameters in lambs during the first four months of life

“…It is influenced by dietary protein intake and is considered the most sensitive indicator for the determination of protein nutritional status in the long term, since changes in its concentrations are detected only after a minimum period of one month due to its low rate of synthesis and degradation (Peixoto and Osório, 2007). According to Silva et al (2010) and Chai et al (2015), lambs older than 30 days already present rumination and become proficient in the use of nitrogenous compounds from the diet, which causes a gradual increase in albumin concentrations until 90 days, as observed in this study. The decrease observed at 120 days, as a delayed response from albumin, in turn, might have been caused mainly by weaning, since depriving the lambs of milk reduces the total dietary protein and energy intake (as observed at 76-90 days; Table 3) and, consequently, the use of available forage protein and albumin synthesis (Fernandes et al, 2012;Santos et al, 2017).…”

Tartrate-resistant acid phosphate as biomarker of bone turnover over the lifespan and different physiologic stages in sheep

“…Because of the latter, blood samples sampling must be drawn at a standardized time [ 15 ]. Age was another influencing factor, with a higher level of ALP found in 1-month old animals, possibly due to synthesis in a variety of tissues, not only due to the bone isoenzyme [ 4 ], and high juvenile metabolism [ 19 ]. Lower levels of ALP were found in sheep over 8 years of age, possibly due to the influence of age in decreasing bone formation.…”