<b>Productive and reproductive parameters in high and low growing Syrian Awassi lambs

Abstract

ABSTRACT. The objective of this study was characterize some productive and reproductive parameters in Syrian Awassi ewe lambs during different age stages. Thirty Syrian Awassi ewe lambs aged around 3 months were divided equally into 2 groups, high and low growing to identify productive and reproductive parameters during different stages. Blood samples were collected to determine progesterone and leptin concentrations. Daily milk samples were collected to determine the average daily production. At puberty, average body weight of higher growing was higher (48.4 kg) than de crescimento low growing (42.8 kg). Average age at puberty was 359.5 and 394.9 days for high and low groups, respectively with no differences. Mating, lambing and fecundity rates were similar among groups. Progesterone concentration was very low and increased rapidly at puberty with a sharp increase during pregnancy, followed by a noticeable decrease post lambing. There were individual variations in leptin concentration with no clear trend in groups. Average leptin concentration at puberty was 2.42 and 2.50 ng mL -1 for higher and low groups, respectively with no difference. Average daily milk production was higher for the higher group (1.495 g day for low grups. Thus, the lambs growing alter produtive and reproductive parameters.Keywords: leptin; milk production; progesterone; puberty.Parâmetros produtivos e reprodutivos de cordeiros Awassi da Síria de taxa rápida e lenta de crescimento RESUMO. O objetivo deste estudo foi caracterizar alguns parâmetros produtivos e reprodutivos em cordeiros sírios Awassi com diferentes estpagio de crescimento. Trinta cordeiros Awassi com cerca de 3 meses de idade foram divididos igualmente em dois grupos: cordeiros de crescimento rápido e lento, para identificar os parâmetros produtivo e reprodutivo, durante diferentes estágios. Foram coletadas amostras de sangue para determinar a concentração de progesterona e leptina. Também, foram coletadas amostras diárias de leite para determinar a média de produção diária. Na puberdade, a média geral dos pesos dos cordeiros de crescimento rápido foi maior (48,4 kg) comparado aos de crescimento lento (42,8 kg). A idade média da puberdade foi de 359,5 e 394,9 dias para o grupo rápido e lento, sem diferenças. As taxas de acasalamento, parto e fecundidade foram semelhantes entres os grupos. A concentração de progesterona foi baixa e aumentou rápidamente na puberdade, com um aumento acentuado durante a gravidez, seguido por um notável decrescimento no pós-parto. Houve variações individuais na concentração de leptina sem uma clara tendência nos grupos. A média de concentração de leptina na puberdade foi de 2,42 e 2,50 ng mL -1 para o grupo de higher and low, respectivamente. A produção diária de leite foi maior para o grupo de crescimento rápido (1.495 g dia -1) comparada com 1.077g dia -1 para os animais de crescimento fraco. Assim, a taxa de crescimento alterou os parâmetros produtivos e reprodutivos.Palavras-chave: Leptina; produção de leite; progesterona; puberdade.

Impact of Pre-pubertal Growth Rate on Pubertal Characteristics of Sohagi Ewe Lambs

“…Ewe lambs in fast-growing group reached firstly to puberty followed by those in mediumgrowing group but ewe lambs in low-growing group were the latest. Similar results were previously conducted by Zarkawi and Al-Daker (2018). They investigated the effect of preweaning growing rate of Syrian Awassi ewe lambs on some productive and reproductive performance.…”

“…While, Kenyon et al, (2014) found that Romney ewe lambs attained the onset puberty at 40-60% of mature live weight. Zarkawi and Al-Daker (2018) reported that fastgrowing ewe lambs achieved onset puberty faster than lowgrowing ewe lambs. Chelikani et al (2003) revealed that about 96% of the variation in attaining puberty is due to prepubertal body weight and average daily gain.…”

Evaluation of Growth Performance, Blood Metabolites and Gene Expression Analysis in Egyptian Sheep Breeds, in Relation to Age

“…The opposite results mentioned by Zarkawi and Al-Daker (2018) they reported for Syrian Awassi ewe lambs that leptin concentrations did not among different age categories from puberty up to maturity and the overall average concentration was (2.50 ± 0.84 ng/mL) from 6 to 12 months of age.…”

Preliminary study regarding the effect of season on haematological parameters in Syrian Awassi rams

“…In Syria, several studies were conducted on Syrian Awassi sheep such as productive and reproductive parameters in Awassi ewe lambs (Zarkawi and Al-Daker, 2018), body weight and reproductive parameters in Awassi ram lambs (Zarkawi and Al-Daker, 2016) and factors affecting serum testosterone levels in growing Syrian Awassi ram lambs (Zarkawi and Salhab, 2005). However, as for haematological parameters, very few studies and reports are available, and as there are no haematological reference values for Syrian Awassi rams so far, therefore, the aim of the current study was to define and establish the haematological reference values for the Syrian Awassi rams and to assess the effect of season.…”