Biology of dairy cows during the transition period : the final frontier?

http://directory.umm.ac.id/Data%20Elmu/jurnal/A/Animal%20Reproduction%20Science/Vol60-61.Issue1-4.Jul2000/1949.pdf

Nutritional interactions with reproductive performance in dairy cattle

Invited Review: Pathology, Etiology, Prevention, and Treatment of Fatty Liver in Dairy Cows *

Neutrophil function and energy status in Holstein cows with uterine health disorders.

Adaptations of Glucose and Long-Chain Fatty Acid Metabolism in Liver of Dairy Cows during the Periparturient Period

This review addresses the suggestion that the decline in dairy reproductive performance, as increasingly observed these days, may be due to a hampered process of metabolic adaptation in early lactating cows. In our opinion, adaptation to the negative energy balance is a gradual process. Because almost all cows do adapt in the long run, it is not possible to classify animals as adapted or non-adapted. The use of risk factors is more appropriate in this case and is discussed in this review. Among them are the body condition score and its derivatives, feed intake, the calculated negative energy balance, and metabolic parameters like the plasma concentration of insulin or the triacylglycerol content in the liver. Moreover, factors that play a role in the link between declined reproductive performance and the metabolic situation of the cow during the early lactating period are discussed. Among these are insulin, insulin-like growth factors, leptin, neuropeptide Y, non-esterified fatty acids, thyroid hormones, urea, and ammonia.

/pdf/metabolic-changes-in-early-lactation-and-impaired-112tgbyw5e.pdf

Metabolic changes in early lactation and impaired reproductive performance in dairy cows.

Effects of weaning pigs to different diets have been investigated in terms of the changes in the small intestinal morphology, and in the absorption of short-chain fatty acids (SCFA) and sodium from the large intestine. One piglet from each of six litters containing nine pigs was sampled on the day of weaning; the other eight piglets were divided into four equal groups and fed different diets as follows: unweaned, weanling diet, or sow's milk at high or low level. Four and seven days after weaning, measurements of the intestinal tissue and contents were made; the plasma concentrations of SCFA, aldosterone and sodium were also measured. The villous height in the small intestine was highest in the unweaned group and greater in the high milk group than in either the weanling diet or low milk group (P < 0.001). Apparently, villous atrophy was due more to the level of feed intake than to the composition of the diet. The concentrations of SCFA in the large intestine and portal blood were highest in the weanling diet group and lowest in the low milk group. The low milk group tended to have higher blood concentrations of aldosterone (P = 0.15), which may have compensated for the low concentrations of SCFA in maintaining a higher percentage of dry matter in the intestine. Pigs fed weanling diet may use the energy from the SCFA to maintain a body weight comparable to that of pigs fed milk at a low level.

Weaning and the Weanling Diet Influence the Villous Height and Crypt Depth in the Small Intestine of Pigs and Alter the Concentrations of Short-Chain Fatty Acids in the Large Intestine and Blood

In dairy cows, overfeeding during the dry period leads to overcondition at calving and to depression of appetite after calving. As a consequence, at calving overconditioned high-producing dairy cows inevitably go into a more severe negative energy balance (NEB) postpartum than cows that have a normal appetite. During the period of NEB, the energy requirements of the cow are satisfied by lipolysis and proteolysis. Lipolysis results in an increased concentration of non esterified fatty acids (NEFA) in the blood. In the liver, these NEFA are predominantly esterified to triacylglycerols (TAG) that are secreted in very low density lipoproteins (VLDL). In early lactation in cows with a severe NEB, the capacity of the liver to maintain the export of the TAG in the form of VLDL in balance with the hepatic TAG production is not always adequate. As a result, the excess amount of TAG accumulates in the liver, leading to fatty infiltration of the liver (hepatic lipidosis or fatty liver). The NEB and/or fatty liver postpartum are frequently associated with postparturient problems. In general, a severe NEB induces changes in biochemical, endocrinological, and metabolic pathways that are responsible for production, maintenance of health, and reproduction of the postparturient dairy cow. These changes include a decrease in blood glucose and insulin concentrations, and an increase in blood NEFA concentrations. High NEFA concentrations caused by intensive lipolysis are accompanied by impairment of the immune system, making the cows more vulnerable to infections. Metabolic diseases such as ketosis, milk fever, and displaced abomasum are related to overcondition at calving. The changes in biochemical, endocrinological, and metabolic pathways are associated with delay of the first visible signs of oestrus, an increase in the interval from calving to first ovulation, a decrease in conception rate, and a prolonged calving interval. It is possible that the increased blood NEFA concentration directly impairs ovarian function.

https://www.tandfonline.com/doi/pdf/10.1080/01652176.1999.9694997

Relationship between overfeeding and overconditioning in the dry period and the problems of high producing dairy cows during the postparturient period

Relationship between overfeeding and overconditioning in the dry period and the problems of high producing dairy cows during the postparturient period. Review paper.

Theo Wensing

Papers

Metabolic changes in early lactation and impaired reproductive performance in dairy cows.

Weaning and the Weanling Diet Influence the Villous Height and Crypt Depth in the Small Intestine of Pigs and Alter the Concentrations of Short-Chain Fatty Acids in the Large Intestine and Blood

Relationship between overfeeding and overconditioning in the dry period and the problems of high producing dairy cows during the postparturient period

Relationship between overfeeding and overconditioning in the dry period and the problems of high producing dairy cows during the postparturient period. Review paper.

Interrelation of fatty acid composition in adipose tissue, serum, and liver of dairy cows during the development of fatty liver postpartum.