The Effect of Increasing Energy and Protein Levels in the Pre-Partum Diet on Colostrum and Lamb Performance in Karakul Sheep

Introduction: This research aimed to explore the Effects of prenatal dietary energy and protein levels on colostrum quality and quantity by using refractometer and performance of lambs up to weaning age in Qara Gol sheep. The postnatal period is critical for newborn ruminants in the onset of their life and moreover their future performance because, they are born without functional immune system for protection against infectious diseases, which will be acquired by the lamb passively through the ingestion of colostrums. In the first 24–36 hours of life, it is of utmost importance that lambs consume colostrum, the first nutrition after birth. In addition to ensuring the supply of antibodies, colostrum has a high concentration of nutrients that will allow body maintenance and survival in the first days of life. Although it is well known that efficient supplement of energy and protein in prepartum time has an effective effect on immune system ability to enhance colostrum quality and quantity but, the different sources of energy and protein may have different consequences and benefits. Moreover, providing sufficient support to fetal growth and body maintenance, adequate support of energy and protein during ewe’s gestation is essential to promote the development of the mammary gland and its colostrum synthesis. Non adequate nutrition of the ewe in late pregnancy may change the colostrum quality and quantity, having negative implications for lamb’s health and survival during the early postnatal period. One of the consequences of changing maternal nutrition is the effect of mammary gland growth and development. Increasing the energy intake, for example, promotes mammogenesis in the ewe. The nutrition available to the ewe during gestation has been shown to influence both the udder development and subsequent lactation performance. Sheep fed 20 % more of metabolizable energy (ME) produced more colostrum within 18 h postpartum but did not alter the serum immunoglobulin G (IgG) concentration in progeny (McGovern et al., 2015). On the other hand, have a feasable method to assay colostrum quality right at parturition time with confidential value could be a precious management protocol in sheep raising. based on what mentioned above, this investigation monitored the effects on different sourses of energy and protein by using different levels on corn, soybean meal and mixed corn and soybean meal on colostrum quality and quantity and blood parameters in sheep and newborn lambs. areted that concentration of blood IGg and ewe colostrum (based on refractometer and ELISA),the concentration of blood metabolites (glucose, urea, total protein, NEFA, beta-hydroxybutyrate and concentration of albumen, insulin, IGF-I and antioxidant) in newborn lambs and also the effect of different sources of ration energy on placenta weight, the amount of colostrum, percentage of lactose, percentage of protein and percentage of colostrum fat and also concentration of IGg and the weight of newborn lambs.
Material and methods: 48 heads of Singleton 2-3 birth bellies pregnant ewes of Gore Gol breed (average alive weight 48.9 ± 2.5 Kg) in 4 groups were randomly assigned to 4 groups including treatment 1, control group, basal deit formulated based on the NRC (2007) recommendations. treatment 2, basal deit with more than 20% metaolizabel energy by increasing corn, treatment 3, basal deit with more than 20% protein by increasing soybean meal and treatment 4, basal deit with more than 20% energy and protein by increasing a mix of soybean meal and corn. Feed consumption of the treatment was controlled daily. The feed offered and leftover was measured everyday. The DMI was estimated by animal based on the feed consumed. Blood samples were collected by venipuncture of the jugular vein at parturition day in ewes and 24 hours after birth in lambs. For analysis of glucose, urea, and total protein protein Pars Azmoon Kites (Iran) was used. NEFA and BHBA were measured by Randox Kites (England) and IgG in lambs' blood was measured by calorimetric method. The birth weights of lamds measured after birth. The amount of colostrum was measured during three times of strips in 24 hours after the parturition and first strip assayed with refractometer.
Results and discussion: Ewes in the control treatment produced less colostrum at the first milking compared to other treatments (P<0.05). Increasing the energy and protein content of the ewes' diet at the end of pregnancy increased the concentration of IgG and lactose in the colostrum compared to the control treatment (P<0.05). Also, ewes in treatment 4 had higher concentrations of unsaturated fatty acids and antioxidants than those fed the control diet (P<0.05), but the concentration of beta-hydroxybutyrate and blood glucose in ewes in treatment 4 was lower compared to the control (P<0.05). Lambs from ewes fed the control treatment had lower blood IgG concentrations and average birth weights compared to other treatments (P<0.05). Adding energy and protein to the mother's diet in the last month of pregnancy affects the amount of colostrum and its components, which increases the percentage of fat and lactose (Swanson et al 2008). It was concluded that a 20% increase in the energy and protein level of the diet 4 weeks before the birth of Karakul ewes can increase the weight of the placenta and the birth weight of the lamb, as well as the quantity and quality of colostrum (in terms of the amount of nutrients and also the level of IgG). Also, limiting energy intake during the final month of gestation has a negative impact on the blood parameters associated with nutrition, leading to decreased IgG levels and increased butyric acid concentrations in the blood, which in turn results in a reduction in both the quantity and quality of colostrum produced by the ewes, as well as a decrease in blood IgG levels in the milk-fed lambs.