Forage allowances offered to pregnant ewes until middle and late gestation: Organ priorities on foetus development

Effect of forage allowance before conception and until mid or late gestation was evaluated for effects on foetal and neonatal weights, carcass, nervous systems, metabolic and reproductive organ weights, body dimensions, and variation in intensity of the effects among organs. Effects of two forage allowances, HFA: high forage allowance (2.9 - 3.8 kg of dry matter (DM)/kg bodyweight (BW)) and LFA: low forage allowance (1.4 - 2.6 kg DM/kg BW) were evaluated from 23 days before conception until 70 or 122 days postpartum. On gestation day 70, nine ewes per treatment, each carrying one male foetus, were euthanized and their foetuses were removed. The foetuses were weighed, their carcass and organ weights were recorded, and their external genitalia dimensions were measured. Nine additional lambs per treatment were euthanized 12 hours after birth and the same data were recorded. Hearts from day 70 LFA foetuses were lighter, their external genitalia were smaller, and their foetal weight tended to be less than in HFA. Newborn lambs from LFA ewes had lighter carcasses, livers, kidneys, adrenal glands and testes, shorter penises, but higher brain to liver weight ratios than in HFA. The cerebellum, brain, and heart weights of LFA and HFA newborn lambs did not differ. Low forage allowance until late gestation influenced both foetal and lamb weights and affected organ weights differentially. Thus, the treatments induced differences in prioritization of nutrients, with the central nervous system receiving the highest priority, and carcass and external genitalia the lowest. Keywords: foetal programming, intrauterine growth restriction, lambs, undernutritio

Efectos de la subnutrición durante la gestación sobre el desarrollo del aparato reproductor del cordero.

ABSTRACTFetal programming by undernourishment refers to the effects of early life subnutrition on organ development later in life. Sheep breeding in Uruguay occurs normally in autumn, with parturitions in late winter or early spring. Since pasture production and quality is lowest in winter, most pregnant sheep are subject to nutrient restriction. We hereby present four experiments which describe deleterious effects of undernourishment during gestation on reproductive organs development of the lambs. We hypothesized that intrauterine subnutrition affects reproductive organs development in male lambs. Three experiments were carried out on natural pasture in Uruguay, and one of them was carried out under indoors, controlled conditions. Our results on 70 day fetuses, newborn lambs, as well as 100 and 200 days old lambs indicatethat subnutrition during early life determines smaller testes and external genitalia, lower scrotal circumference, and lower numbers of Sertoli cells which may limit the reproductive potential of rams in adulthood

EFFECTS OF INTRAUTERINE NUTRITION ON FETAL PROGRAMMING OF REPRODUCTIVE ORGANS AND THE FUTURE REPRODUCTIVE PERFORMANCE IN SHEEP

The effects of uterine undernutrition during the embryonic and fetal development has been of concern in human medicine due to the consequences on the health and welfare of the people it causes. However, in animal production it is in just the past two decades that the issue has gained interest from researchers. Animal production based on native pasture grazing systems often presets periods of under nutrition during gestation, so the topic is of particular interest to our region. The aim of this paper is to review the literature on the effects of nutrition, with special emphasis on undernutrition of the pregnant ewe on the intrauterine development of the reproductive tract of both male and female offspring, and the reproductive performance of the adult ewe and ram

Suplementación con glicerina cruda y afrechillo de arroz entero a vacas de carne pastoreando campo natural. (Supplementation of beef cows grazing natural pasture with crude glycerin and whole rice bran).

RESUMEN.Con el objetivo de evaluar los efectos de la suplementación con glicerina cruda (GC) y afrechillo de arroz entero (AA) sobre la dinámica ruminal, la cinética de degradación de la materia seca (MS), el consumo de forraje y variables plasmáticas asociadas al balance energético en vacas de carne pastoreando campo natural, cuatro vacas fistuladas en el rumen fueron asignadas a un cuadrado latino 4 × 4 con un período adicional. Los tratamientos evaluados fueron: suplementación con GC (550 mL/vaca/día), suplementación con AA (1kg de MS/vaca/día), suplementación con GC + AA (550 mL/vaca/día + 1 kg de MS/vaca/día) y sin suplementación (CON). La asignación diaria de forraje para todos los tratamientos fue 10 % del peso vivo. La GC asociada o no al AA disminuyó el pH ruminal en las primeras seis horas pos-suplementación, pero no afectó ningún parámetro de degradabilidad de la MS del forraje. Comparada con CON la suplementación con GC disminuyó el consumo de forraje pero no afectó el consumo de MS total ni de energía metabolizable (EM). Ni el consumo de forraje, ni el consumo total fueron diferentes entre la suplementación con GC + AA y AA, sin embargo el consumo de EM fue mayor para GC + AA en comparación con el resto. La suplementación con GC + AA aumentó la concentración plasmática de glucosa e insulina sin afectar la de B-hydroxibutirato. De los suplementos ensayados, la mezcla GC + AA (mayor nivel de suplementación) logró los mejores resultados biológicos..-.-.-.-.-.-.-.-.-.-.-.-.-.-.-..SUMMARY.To study the effects of supplementation with crude glycerin (GC) and whole rice bran (AA) on ruminal dynamics, kinetics of dry matter (DM) degradation, forage intake and plasma variables associated with energy balance in beef cows grazing natural pasture, four rumen fistulated cows were allocated to a latin square 4 × 4 with an additional period. The treatments were: supplementation with GC (550 mL/cow/day), supplementation with AA (1 kg DM/cow/day), supplementation with GC + AA (550 mL/cow/day + 1 kg DM/cow/day) and without supplementation (CON). The daily forage allowance for all treatments was 10 % of live weight. GC associated or not to AA decreased ruminal pH on the first six hours pos-supplementation, but did not affect any parameters of degradability of forage DM. GC supplementation decreased forage intake but did not affect total DM intake and metabolizable energy (ME) compared with CON. GC + AA and AA supplementation did not differ on intake of forage and total DM, however the ME intake was higher for GC + AA compared to the rest. GC + AA supplementation increased plasma concentration of glucose and insulin without affecting B-hydroxibutirate. Among the supplements tested, GC + AA mixture (higher level of supplementation) achieved the best biological results

Effects of rice bran and glycerin supplementation on metabolic and productive responses of beef cows.

ABSTRACT:Fifty-seven primiparous Angus, Hereford, and crossbred cows were used to study the effect of strategic supplementation on metabolic, productive, and reproductive responses. The experiment had two periods including four phases: prepartum supplementation (phase I; 52 days), early postpartum (phase II; 43 days), pre-mating supplementation (phase III; 21 days), and the last phase including mating, gestation, and lactation until weaning (phase IV; 103 days). Phases I and II were considered as period 1, and phases III and IV were considered as period 2. During phase I (−52±2 days before calving to birth), half of the cows received a supplement (S-), and the rest only grazed native swards (C-). For phase III (59±2 days postpartum [DPP] until mating), cows from the previous treatments (C- or S-) were sorted in two levels of pre-mating supplementation, supplemented (-S) or not supplemented (-C), resulting in four treatment combinations (CC, CS, SC, and SS). The supplement was 1 kg dry matter/cow per day of whole rice bran and 550 mL/cow per day of crude glycerin. In period 1, cows receiving prepartum supplementation increased concentration of cholesterol, glucose, and albumin and decreased concentration of non-esterified fatty acids, beta-hydroxybutyrate, and urea. This improvement in energy balance was reflected in a higher body condition score at calving. Alternatively, in period 2, pre-mating supplementation only increased cholesterol concentration. None of the supplementation periods affected the weaning weight of calves. Prepartum, but not pre-mating, supplementation increased total pregnancy rate. A short prepartum supplementation improves pregnancy rate of primiparous cows managed under extensive production systems. However, there is no additional benefit of supplementation during the pre-mating period

Una menor oferta de campo natural gestacional afecta el desarrollo muscular fetal-neonatal y repercute sobre el peso y la composición fibrilar en corderos pesados.

ABSTRACTThe present study evaluated the effects of maternal undernutrition induced by a lower natural pasture allowance during gestation on the histological characteristics of fetal, neonatal and adult Semitendinosus ovine muscle. Two experiments were carried out.In experiment 1, ewes were assigned to two nutritional treatments from 23 days before conception until day 123 of gestation: High pasture allowance (HPA) ewes grazed on natural grasslands at 10-12 kg dry matter (DM)/100 kg of live weight (LW)/day, while low pasture allowance (LPA) ewes grazed at 5-8 kg DM /100 kg of LW/day. In experiment 2, ewes were assigned to two natural pasture allowances between days 30 and 143 of gestation: HPA ewes grazed on 14-20 kg of DM/100kg of LW/day; while LPA ewes grazed on 6?10 kg of DM/100 kg of LW/day.In experiment 1, samples were taken from 70-day old fetuses and newborn lambs to evaluate muscle histology, while in experiment 2 samples were taken from 200-day old heavy-lambs which were equally ad libitum fed from lambing until slaughtering. Maternal undernutrition reduced the number of secondary fibers and the number of nuclei/ fasciculi in fetal muscles. Maternal undernutrition reduced the mean fiber diameter and the number of nuclei per fiber and increased the proportion of non-muscle tissue in newborn lambs. Furthermore, maternal undernutrition reduced the weight and increased the proportion of oxidative fibers in the Semitendinosus of heavy-lambs. Our results suggest that a lower maternal pasture allowance during gestation affects myogenesis with possible future effects over meatproducing performance