Principal descriptors of body condition score in Holstein cows.

Interrelationships between energy balance and postpartum reproductive function in dairy cattle.

Intrauterine growth retardation (IUGR), defined as impaired growth and development of the mammalian embryo/fetus or its organs during pregnancy, is a major concern in domestic animal production. Fetal growth restriction reduces neonatal survival, has a permanent stunting effect on postnatal growth and the efficiency of feed/forage utilization in offspring, negatively affects whole body composition and meat quality, and impairs long-term health and athletic performance. Knowledge of the underlying mechanisms has important implications for the prevention of IUGR and is crucial for enhancing the efficiency of livestock production and animal health. Fetal growth within the uterus is a complex biological event influenced by genetic, epigenetic, and environmental factors, as well as maternal maturity. These factors impact on the size and functional capacity of the placenta, uteroplacental blood flows, transfer of nutrients and oxygen from mother to fetus, conceptus nutrient availability, the endocrine milieu, and metabolic pathways. Alterations in fetal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology, metabolism, and postnatal growth of the offspring. Impaired placental syntheses of nitric oxide (a major vasodilator and angiogenic factor) and polyamines (key regulators of DNA and protein synthesis) may provide a unified explanation for the etiology of IUGR in response to maternal undernutrition and overnutrition. There is growing evidence that maternal nutritional status can alter the epigenetic state (stable alterations of gene expression through DNA methylation and histone modifications) of the fetal genome. This may provide a molecular mechanism for the role of maternal nutrition on fetal programming and genomic imprinting. Innovative interdisciplinary research in the areas of nutrition, reproductive physiology, and vascular biology will play an important role in designing the next generation of nutrient-balanced gestation diets and developing new tools for livestock management that will enhance the efficiency of animal production and improve animal well being.

Board-invited review: intrauterine growth retardation: implications for the animal sciences.

https://hal.archives-ouvertes.fr/hal-01173575/document

Invited review: Body condition score and its association with dairy cow productivity, health, and welfare

Pregnancy, decreased feed intake during late gestation, lactogenesis, and parturition have dramatic effects on metabolism in dairy cows during the transition period from 3 wk before calving to 3 wk after calving. Increases in plasma NEFA occur during the 10 d before calving and may precede the decrease in feed intake. Plasma NEFA concentrations are highest at calving and decrease rapidly after calving. Plasma glucose concentration decreases during the transition period except for a transient increase associated with calving. Hepatic glycogen is reduced and lipid is increased during the transition period. Feed intake is usually decreased 30 to 35% during the final 3 wk prepartum, but negative energy and protein balances are not as severe as during the week following parturition. Prepartum feed intake is positively correlated to postpartum feed intake; therefore, efforts to maximize feed intake should begin before calving. Overconditioned cows may be more susceptible to a prepartum decrease in feed intake. Increasing nutrient density of the diet during the transition period may enhance feed intake. Feeding more fermentable carbohydrate during the prepartum transition period may acclimate the microbial population to lactation diets, promote development of ruminal papillae, increase absorptive capacity of the rumen epithelium, and reduce lipolysis by delivering more glucogenic precursor to the liver and enhancing blood insulin. Supplementing fat to transition diets does not seem to alleviate health problems associated with negative energy balance. Enhancing amino acid absorption by the prepartum cow may improve lactation performance and health, although mechanisms of action have not been identified.

https://webpages.uidaho.edu/ruminant_nutrition/reading materials 511/nutrient metabolism/nutrinet metabolism- grummer 1995.pdf

Impact of changes in organic nutrient metabolism on feeding the transition dairy cow.

Relationships of body condition score to production variables in high producing Holstein dairy cattle.

The objective of this study was to compare conception to artificial insemination (AI) services in dairy cattle when semen was deposited into the uterine body or into both uterine horns (cornual insemination). Nine herdsman inseminators (HI) in four commercial dairy herds in Washington constituted the experimental units. Herds ranged in size from 393 cows to 964 cows. The duration of the experiment was 12 mo in three herds and 18 mo in the fourth herd. At the beginning of the experiment all inseminators were trained to deposit semen in the body of the uterus. Inseminators were instructed to use this method for 6 mo. Following employment of body deposition, the same inseminators were retrained to deposit one-half of the semen into the right uterine horn and one-half into the left uterine horn. Cornual inseminations were performed for 6 mo. A total of 4,178 services constituted the data set. Milk samples were collected from cows on the day of insemination and later were assayed for progesterone (P4). There was variation (P less than .01) in conception associated with month of insemination and insemination method (P less than .001). The monthly variation was not associated with season of the year. Least squares means for conception when semen was deposited in the uterine body was 44.7%, compared with 64.6% when cornual insemination was employed. The insemination treatment X inseminator interaction was not significant. Results suggest that cornual insemination provides an alternative to deposition of semen in the uterine body.

Joe K. Hillers

Papers

Relationships of body condition score to production variables in high producing Holstein dairy cattle.

Influence of Cornual Insemination on Conception in Dairy Cattle

Relationship Between Vitamin A and β-Carotene in Blood Plasma and Milk and Mastitis in Holsteins

Effects of production, season, age of cow, days dry, and days in milk on conception to first service in large commercial dairy herds.

Regulation of bovine adipose tissue metabolism during lactation. 2. Lipolysis response to milk production and energy intake.