Effects of Lateral Hypothalamic Lesions on Placentophagia in Virgin, Primiparous, and Multiparous Rats

Lesions of the lateral hypothalamus (LH) were produced in pregnant and nonpregnant female rats through chronically implanted electrodes to investigate the effect of LH damage on placentophagia. Other variables investigated were prior parturitional experience and stimulus properties of the placenta. Lesions were produced under ether anesthesia 24 hr. prior to parturition in pregnant females and 24 hr. prior to placenta presentation in nonpregnant females.\ud The LH lesions produced aphagia to a liquid diet. Pregnancy was not a significant variable in the initiation of placentophagia, but prior parturitional experience was a critical variable. Virgin and primiparous females did not exhibit placentophagia following LH damage, but multiparous females would eat placenta whenever the opportunity arose, independently of LH damage and pregnancy

Effects of maternal subnutrition during early pregnancy on cow hematological profiles and offspring physiology and vitality in two beef breeds

This experiment evaluated the effects of subnutrition during early gestation on hematology in cows (Bos Taurus) and on hematological, metabolic, endocrine, and vitality parameters in their calves. Parda de Montaña and Pirenaica dams were inseminated and assigned to either a control (CONTROL, 100% requirements) or a nutrient‐restricted group (SUBNUT, 65%) during the first third of gestation. Dam blood samples were collected on days 20 and 253 of gestation, and calf samples were obtained during the first days of life. Pirenaica dams presented higher red series parameters than Parda de Montaña dams, both in the first and the last months of gestation. During early pregnancy, granulocyte numbers and mean corpuscular hemoglobin were lower in Pirenaica‐SUBNUT than in Pirenaica‐CONTROL cows. Calves from the SUBNUT cows did not show a physiological reduction in red series values in early life, suggesting later maturation of the hematopoietic system. Poor maternal nutrition affected calf endocrine parameters. Newborns from dystocic parturitions showed lower NEFA concentrations and weaker vitality responses. In conclusion, maternal nutrition had short‐term effects on cow hematology, Pirenaica cows showing a higher susceptibility to undernutrition; and a long‐term effect on their offspring endocrinology, SUBNUT newborns showing lower levels of IGF‐1 and higher levels of cortisol.This work was supported by the Spanish Ministry of Economy and Business and the European Union Regional Development Funds (INIA RTA 2013‐00059‐C02 and INIA RZP 2015‐001) and the Government of Aragon under the Grant Research Group Funds (A14_17R). A. Noya received a PhD grant from INIA‐Government of Aragon

Demographic performance of local sheep and goat breeds in two agro-ecological zones in Egypt

Small breeders in Egypt raise locally adapted sheep and goats breeds, which have the ability to produce and reproduce under the prevailing harsh conditions. Improving resilience of their production system is a major challenge to support socioeconomic development. However, little is known about the productive abilities of these breeds in small farming systems. The present work is an attempt to assess the performance of local breeds in small farming systems, and their capacity to cope with feed scarcity and harsh climatic conditions. In 2018, a retrospective survey was conducted over 12 month period to assess demographic rates of 25 local Barki sheep and goat flocks in the rain-fed area of Coastal Zone of Western Desert (CZWD) and 28 local Saidi sheep and goat flocks under the hot intensive agriculture system in Upper Egypt (UE). Flocks are larger, reproductive performance and offtake rates are higher (and mortality lower) in the CZWD, a region specialized in small ruminant breeding whereas it remains a secondary activity in Upper Egypt. The marketing season is mainly during Korban Eid festival. Their main challenges are frequent incidence of drought in the CZWD and high prices of feed stuffs in both sites. Our study suggests breeders have different strategies in UE and the CZWD when confronted with feed shortage. Breeders in the CZWD purchase feed to maintain high herd productivity whereas in UE small ruminant breeding is a minor activity with less productive animals that are resilient to feed shortage

The biopsychology of maternal behavior in nonhuman mammals

The term “maternal behavior,” when applied to nonhuman mammals, includes the behaviors exhibited in preparation for the arrival of newborn, in the care and protection of the newly arrived young, and in the weaning of those young, and represents a complex predictable pattern that is often regarded as a single, comprehensive, species-specific phenomenon. Although the delivering first-time mammalian mother is immediately and appropriately maternal, a maternal “virgin” with no prior exposure to young does not show immediate and appropriate behavior toward foster young. Nevertheless, the virgin female, and indeed the male, possess the neural circuitry that underlies the pattern referred to as maternal behavior, despite not exhibiting the pattern under normal circumstances. At parturition, or after extensive exposure to young, what emerges appears to be a single stereotyped maternal behavior pattern. However, it is actually a smoothly coordinated constellation of simpler actions with proximate causes that, when sequenced properly, have the appearance of a motivated, purposive, adaptive, pattern of caretaking. Over the past 50 years, much research has focused on finding the principal external and internal factors that convert the nonmaternal behavior patterns of the nonpregnant nullipara, the virgin, to the almost immediate and intense maternal behavior characteristic of the puerpera, the mother. This review is an attempt to summarize the many comprehensive, even encyclopedic, reviews of these factors, with an emphasis on brain mechanisms, and to highlight the gaps that remain in understanding the processes involved in the almost immediate onset of maternal caretaking behaviors observed in mammals at delivery. Where possible, the reader is directed to some of those excellent reviews

Augmented Hypothalamic Corticotrophin-Releasing Hormone mRNA and Corticosterone Responses to Stress in Adult Rats Exposed to Perinatal Hypoxia

Stressful events before or just after parturition alter the subsequent phenotypical response to stress in a general process termed programming. Hypoxia during the period before and during parturition, and in the postnatal period, is one of the most common causes of perinatal distress, morbidity, and mortality. We have found that perinatal hypoxia (prenatal day 19 to postnatal day 14) augmented the corticosterone response to stress and increased basal corticotrophin-releasing hormone (CRH) mRNA levels in the parvocellular portion of the paraventricular nucleus (PVN) in 6-month-old rats. There was no effect on the levels of hypothalamic parvocellular PVN vasopressin mRNA, anterior pituitary pro-opiomelanocortin or CRH receptor-1 mRNA, or hippocampus glucocorticoid receptor mRNA. We conclude that hypoxia spanning the period just before and for several weeks after parturition programmes the hypothalamic-pituitary-adrenal axis to hyper-respond to acute stress in adulthood, probably as a result of drive from the parvocellular CRH neurones

Predicting the Onset of Parturition by Determining Calcium in Prepartum Milk of Sheep

Multiple methods of pregnancy detection can be used in sheep production. The gestation period for sheep is usually between 144 and 150 days; however, depending on the breed and age of the ewes, this number can vary. A breeding marker, such as a breeding crayon, is used to detect when the ewe is bred by the ram, and the date the ewe will lamb is typically calculated based on an average 145-day gestation. Unfortunately, this method provides only a rough estimate of when the ewe could lamb. In addition, because sheep routinely give birth to multiples (twins, triplets, and, sometimes, quadruplets), ewes are renowned for dystocia; thus, the ability to pinpoint the time of parturition to a 24-hour, rather than a five-day, window would enable sheep producers to be prepared for any difficulties, thereby reducing newborn lamb mortality. In horses, the time of parturition can be detected within 24 to 48 hours by measuring calcium concentrations in prepartum milk using the Chemetrics K-1700 testing system. Therefore, the objective of this research was to test the effectiveness of measuring calcium concentrations in prepartum ewe’s milk to predict time of parturition in pregnant ewes. The study was designed to collect 10 to 20 mL of ewe’s milk twice daily, beginning four days before the calculated date of parturition until lambing. Because the Chemetrics K-1700 testing system is a rapid-test, milk calcium concentrations will be determined within minutes of hand-milking each ewe. It is standard practice to collect “extra” colostrum for orphaned or sickly lambs roughly 12 hours postpartum and after the newborn lamb(s) have ingested sufficient quantities of their mother’s colostrum and establish their maternal bonds. Therefore, at approximately 12 hours postpartum, an approximate 25-mL sample of colostrum was collected to measure the immunoglobulin quality of the colostrum using three methods (Colostrum Refractometer, Antifreeze tester, and Equine Colostrometer. Unfortunately, a large enough sample size was not collected to accurately analyze the milk samples using the Chemetrics K-1700. When we analyzed the calcium levels in the colostrum, we found that the colostrum quality was similar using the Anti-freeze tester to that of the Colostrum Refractometer, and was significantly different than the Equine Colostrometer. The Anti-freeze tester was also more highly correlated to the Colostrum Refractometer than that of the Equine Colostrometer. Keywords: sheep, colostrum, immunoglobulin quality, mammary secretion

Effect of oleic acid supplementation on prostaglandin production in maternal endometrial and fetal allantochorion cells isolated from late gestation ewes

Elevated circulating non-esterified fatty acids including oleic acid (OA) are associated with many pregnancy related complications. Prostaglandins (PGs) play crucial roles during parturition. We investigated the effect of OA supplementation on PG production using an in vitro model of ovine placenta

Drying off the dairy cow

Most dairy cows generally have a non-lactating, “dry period” prior to parturition. As the milk production of dairy cows has increased dramatically during the last decades, cows managed conventionally with a 12 to 13 month-calving interval are dried off (DO) while still producing significant quantities of milk. The DO period is probably one of the most physiologically demanding periods for the high-yielding dairy cow, and may negatively affect animal welfare, but few studies have been performed in this area. Therefore, the general aim of the present work was to investigate how different DO procedures and milk yield at DO affect metabolism and udder health of the dairy cow. Furthermore, the effects of different calving intervals and breed were also evaluated. Three studies are included in this thesis. In the first study cows were randomly assigned to two different feeding treatments. One group was fed straw ad libitum, while the other group was fed silage [4 kg dry matter (DM)] daily and straw ad libitum to evaluate metabolic changes and health during DO. In the second study, the effects of daily milk yield at DO, different calving intervals (12 and 15 months) and breed on metabolism and udder health were studied when feeding additional silage at DO. The third study was conducted on over 10 000 lactating cows and the association between daily milk yield prior to DO and veterinary-treated clinical mastitis (VTCM) from DO until early lactation was evaluated. The overall results of this thesis show that extensively restrictive feeding DO protocols may have negative effects on metabolism. The plasma concentration of non-esterified fatty acids (NEFA) was markedly elevated during DO as an effect of restrictive feeding. Furthermore, plasma NEFA was related to the milk yield prior to DO. Feeding straw only during DO affected the rumen environment as shown by increased pH, a reduced concentration of volatile fatty acids, urea, and lower number of protozoa. Restrictive feeding also increased the plasma cortisol, which indicates an elevated metabolic load in this group. In addition, high milk yield at DO increased the risk for VTCM and the number of open teat canals during the dry period. Swedish Holsteins were at higher risk for VTCM from DO until early lactation compared to Swedish Red and White cows. In conclusion, this thesis shows that the common DO procedure to feed straw only may give rise to metabolic disturbances. However, this might be avoided without any apparent negative effects on udder health if a limited amount of silage is added during DO. As high daily milk yields at DO increase the risk for mastitis, alternative ways to reduce the milk yield at DO should be considered

Milk production and survival of spring-calving carryover cows in New Zealand dairy herds : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Manawatu, New Zealand

Non-pregnant cows are generally culled from dairy herds and replaced with two-year-old heifers. Alternatively, non-pregnant cows can be dried-off at the end of lactation, retained for one year (carried over), before being mated and returned to a milking herd in the following year. In this study, calving interval was used as a tool to identify and define the carryover cow population in spring-calving dairy herds. Linear modelling methods were used to compare carryover cow milk production with that of heifers, lactation-matched and age-matched non-carryover cows. Lastly, the survival for second-lactation carryover cows was compared with that of two-year-old heifers and lactation-matched non-carryover cows. Results showed that annually, 2.5% of spring-calving cows had returned to a milking herd after a carryover period in the previous year. Of those carryover cows, 43% returned to a milking herd at four years old, after failing to conceive in their first lactation. Most (69%) dairy herds contained less than 5% carryover cows and 17% of dairy herds comprised of zero carryover cows. The difference between the proportion of Holstein-Friesian in the carryover cow and non-carryover cow group was minimal (2%) but statistically greater (P<0.01) for the carryover cow group. Estimated breeding values (EBVs) for milk traits (milk yield, fat yield, protein yield and somatic cell count) were greater (P<0.01), but fertility EBVs were lower (P<0.01) for the carryover cow group in the year when they failed to conceive, compared to those for the non-carryover cow group. These were reflected in greater (P<0.01) selection indices (Breeding Worth and Production Worth) for carryover cows. After the carryover period, EBVs for milk traits and fertility decreased, and Breeding Worth was lower (P<0.01) for the carryover cow group, compared to the non-carryover cow group. Carryover cow milk yield, fat yield, protein yield and somatic cell score was greater (P<0.01) than those for heifers, lactation-matched and age-matched non-carryover cows in their first carryover year. This milk production advantage was maintained for up to three carryover years, if the carryover cow maintained an annual calving pattern, but at a decreasing rate. The probability of survival (days) was lower (P<0.01) for second-lactation carryover cows when compared to heifers and lactation-matched non-carryover cows. These findings are important for the New Zealand dairy industry as they can aid on-farm culling (removal from the herd) decisions