Mid-pregnancy ewe shearing and the effects on fetus liver and muscle glycoprotein deposits
João Carlos Morini Junior, Adriana Caroprezo Morini, Lina Castelo Branco Motta, Carlos Eduardo Ambrosio, Phelipe Oliveira Favaron, Flávia Thomaz Verechia Rodrigues, Luiz Alberto Oliveira Ribeiro, Luciana Relly Bertolini, Marcelo Bertolini, Maria Angélica Miglino, Pedro Primo Bombonato
Abstract
The reason why shearing ewes in mid-pregnancy does increase the lamb birth weight is not completely clears. Therefore, we focused on the analyses of the deposition of glycogen in different fetal tissues to investigate this issue. Thirteen pregnant Australian Merino ewes, raised in native pasture, were separated in two groups. One group (n = 7) was shorn (SE) at 70 days of pregnancy, whereas another group (n = 6) remained unshorn (NSE). Cesarean section was conducted in all the ewes at near parturition, when placenta and fetuses sampling were collected. Placenta, liver and muscle samples were fixed and stained with glycoprotein-reactive acid-Schiff acid for analysis under light microscopy. The quantification of these glycoproteins was performed with the support of a program that analyzes the measurement of the intensity of staining by field. Five random fields from each sample were used, where statistical analyzes was used as normal test T. Among the analyzed regions, the deposition of glycoprotein between SE and NSE groups was statistically different in the hepatic portal vein (54,499.23 µm2 in SE and 34,830.73 µm2 in NSE) and in the total muscle area of the sample fragment (41,128, 7 µm2 and 31,942.7 µm2, respectively; P < 0.05). We conclude that shearing ewes at the 70th day of gestation lead to accumulation of glycoproteins in the liver and muscle of fetuses, which may be responsible for the increase in birth weights in that group.
Keywords
References
Alexander G. 1964. Studies on the placenta of the sheep (Ovis aries l.). J Reprod Fertil, 7:289-305.
Banchero G, Vázquez A, Montossi F, Barbieri I, Quintans G. 2010. Pre-partum shearing of ewes under pastoral conditions improves the early vigour of both single and twin lambs. Anim Prod Sci, 50:309-314.
Barbieri ID, Montossi F, Vinoles C, Kenyon. 2018. Time of shearing the ewe not only affects lamb live weight and survival at birth and weaning, but also ewe wool production and quality. New Zeal J Agr Res, 61:57-66.
Black HJ, Chestnutt DMB. 1990. Influence of shearing regime and grass silage quality on the performance of pregnant ewes. Anim Prod, 51:573-582.
Corner RA, Keynon PR, Stafford JK, West DM, Oliver MH. 2006. The effect of mid-pregnancy shearing or yarding stress on ewe post-natal behaviour and the birth weight and post-natal behaviour of their lambs. Livest Sci, 102:121-129.
Corner RA, Keynin PR. Stafford KJ, West DM, Oliver MH. 2007. The effect of mid-pregnancy shearing and litter size on lamb birth weight and postnatal plasma cortisol response. Small Rumin Res, 73:115-121.
Cunningham JG. 1999. Tratado de fisiologia veterinária. 2ed. Rio de Janeiro: Guanabara Koogan. 304:291-299
Dwyer CM, Morgan CA. 2006. Maintence of body temperature in the neonatal lamb: Effects of breed birth weight, and litter size. J Anim Sci, 84:1093-1101.
Elizalde HF, Carson AF, Munõz C. 2018. Effects of sire genotype on lamb performance at weaning in extensive sheep systems. Animal, 1-8. doi: 10.1017/S1751731118000848.
Godfrey RW, Preston WD, Joseph SR, LaPlace L, Hillman PE, Gebremedhin KG, Lee CN, Collier RJ. 2017. Evaluating the impact of breed, pregnancy, and hair coat on body temperature and sweating rate of hair sheep ewes in the tropics. J Anim Sci, 95:2936-2942.
Guyoti VM, Farias MS, Dalmolin ML, Plo CH, Schmidt V, Gonzalez FD. 2015. Effect of shearing during pregnancy on productive performance in the post-partum period of ewes on extensive husbandry. Ciênc Anim Bras, 16:217-224.
Junqueira LC, Carneiro J. 2004. Histologia básica. 10ed. Rio de Janeiro: Guanabara Koogan. 488p.
Kenyon PR, Revell DK, Morris ST. 2002. Mid-pregnancy shearing can increase birthweight and survival to weaning of multiple-born lambs under commercial conditions. Aust J Exp Agr, 46:821-825.
Kenyon PR, Morel PCH, Morris ST. 2004. Effect of liveweight and condition score of ewes at mating, and shearing mid-pregnancy, on birthweights and growth rates of twin lambs to weaning. N Z Vet J, 52:145-149.
Kenyon PR, Sherlock RG, Parkinson TJ, Morris ST. 2006. The effect of maternal shearing and thyroid hormone treatments in mid pregnancy on the birth weight, follicle, and wool characteristics of lambs. New Zeal J Agr Res, 48:293-300.
Labeur L, Villiers G, Small AH, Hinch GN, Schomelzl S. 2017. Infrared thermal imaging as a method to evaluate heat loss in newborn lambs. Res Vet Sci, 115:517-522.
McCoard SA, Henederson HV, Knol FW, Dowling SK, Webster JR. 2014. Infrared thermal imaging as a method to study thermogenesis n the neonatal lamb. Anim Prod Sci, 54:1497-1501.
Morris ST, Mccutcheon SN. 1997. Selective enhancement of growth in twin fetuses by shearing ewes in early gestation. Anim Sci, 65:105-110.
Morris ST, Mcuthcheon SN, Revell DK. 2000. Birth weight responses to shearing ewes in early to mid gestation. Anim Sci, 70:363-369.
Revell DK, Main SF, Breier BH, Cottam YH, Hennies M, Mccutheon SN. 2000. Metabolic responses to mid-pregnancy shearing that are associated with a selective increase in the birth weight of twin lambs. Domest Anim Endocrinol, 18:409-422.
Revell DK, Morris ST, Cottam YH, Hanna JE, Thomas DG, Brown S, Mccutcheon SN. 2002. Shearing ewes at mid-pregnancy is associated with changes in fetal growth and development. Aust J Agric Res, 53:697-705.
Ribeiro LAO, Brito MA, Mattos RC. 2010. Ewes shorn and unshorn during pregnancy in South Brasil: effects on body condition score and lamb birth weight. Braz J Vet Res Anim, 47:111-117.
Roussel S, Hemsworth PH, Boissy A, Duvaux-Ponter C. 2004. Effects of repeated stress during pregnancy in ewes on the behavioural and physiological responses to stressful events and birth weight of their offspring. Appl Anim Behav Sci, 85:259-276.
Smeaton DC, Bown MD, Clayton JB. 2000. Optimum liveweight, feed intake, reproduction, and calf output in beef cows on North Island hill country, New Zealand. New Zeal J Agr Res, 43:71-82.
Symonds ME, Bryant MJ, Lomax MA. 1986. The effect of shearing on the energy metabolism of the pregnant ewe. Brit J Nutr, 56:635-643.
Toboga SR, Romanelli PF, Felisbino SL, Borges LF. 2003. Acompanhamento das alterações post-mortem (glicólise) no músculo do jacaré do pantanal (Caiman crocodilus yacare). Ciên Tecnol Aliment, 22:70-75.
Wiernspenger NF. 2005. Is non-insulin dependent glucose uptake a therapeutic alternative? Part 1: physiology, mechanisms and role of non insulin-dependent glucose uptake in type 2 diabetes. Diabetes Metab, 31:415-426.
Facebook
Google+
Twitter
LinkedIn
Mendeley
StumbleUpon
CiteULike
Reddit
Email