Milk fatty acids as indicators of delayed commencement of luteal activity in dairy cows in early lactation.

Excessive mobilization of adipose reserves due to severe negative energy balance in early lactation may be detrimental to dairy cow fertility at individual and herd level. Reproductive efficiency is one of the main factors influencing herd profitability and a strategy for early detection and management of cows with delayed resumption of cyclicity will result higher conception rate, decreased proportion of cows with extended lactation, fewer inseminations per conception and lower culling rates due to reproductive disorders. Using two groups of dairy cows (Holstein n = 37, Swedish Red breed [SRB] n = 49), we investigated potential differences between cows with different commencement of luteal activity (CLA) and the feasibility of using milk fatty acids (MFAs) as predictors of delayed CLA.

Full-lactation performance of multiparous dairy cows with differing residual feed intake.

Residual feed intake (RFI) is an efficiency trait underpinning profitability and environmental sustainability in dairy production. This study compared performance during a complete lactation of 36 multiparous dairy cows divided into three equal-sized groups with high (HRFI), intermediate (IRFI) or low RFI (LRFI). Residual feed intake was determined by two different equations.

Genetic parameters of forage dry matter intake and milk produced from forage in Swedish Red and Holstein dairy cows.

High-yielding dairy cows are often fed high proportions of cereal grain and pulses. For several reasons, it would be desirable to replace these feed sources with forage, which is not suitable for human consumption. Feeding large amounts of forage to dairy cows could also make dairy production more publicly acceptable in the future.

Whole-lactation feed intake, milk yield, and energy balance of Holstein and Swedish Red dairy cows fed grass-clover silage and 2 levels of byproduct-based concentrate.

Ruminants can produce meat and milk from fibrous feed and byproducts not suitable for human consumption. However, high-yielding dairy cows are generally fed a high proportion of cereal grain and pulses, which could be consumed directly by humans. If high production of dairy cows could be maintained with ingredients of low human interest, the sustainability of dairy production would improve.

An observational study of the dry period length and its relation to milk yield, health, and fertility in two dairy cow breeds.

This study evaluated associations between dry period length (DPL) in dairy cows and energy-corrected milk (ECM) production, health, and fertility, using a dataset involving 78 577 lactations in cows of two breeds, Swedish Red (SR) and Swedish Holstein (SH). Herds with at least 20 cows and at least 20 % purebred SR and at least 20 % SH during the year 2015/2016 were included in the dataset. Cows were divided into parity groups 2 and 3 or older and DPL was classified into six 10-day groups (30-39 to 80-89 d).

Effects of replacing wheat starch with glycerol on methane emissions, milk production, and feed efficiency in dairy cows fed grass silage-based diets.

To lower the effect of climate change from cattle production, we should aim at decreasing their enteric methane emissions per kilogram of milk or meat. Glycerol may be absorbed through the rumen epithelium and would consequently be less available to microbes in the rumen. Glycerol could thus supply dairy cows with energy for milk production without contributing much to methane production.

The effect of 17β-estradiol on lactose in plasma and urine in dairy cows in late lactation.

The aim of this study was to investigate the effect of 17β-estradiol on mammary tight junctions in cows in late lactation. The experiment included five non-pregnant cows around day 290 in lactation. The cows received injections of 17β-estradiol for six days.

Replacing human-edible feed ingredients with by-products increases net food production efficiency in dairy cows.

Global demand for food is increasing, and use of large amounts of potentially human-edible feedstuffs for dairy cows is an important concern. The present study examined whether feeding a by-product-based concentrate combined with high-quality grass silage to high-producing dairy cows affected feed intake and milk production compared with a conventional diet, as well as the effect on efficiency of human food production. In a changeover experiment with four 21-d periods, 24 dairy cows in mid-lactation were offered 9.

Effects of supplementing different levels of sun-dried groundnut foliage on intake, apparent digestibility and nitrogen metabolism in cattle offered a basal diet of a mixture of rice straw and para grass.

Eight male Cambodian yellow cattle, initial body weight (BW) 136 ± 11.9 (±SD) kg; age 20 ± 2.5 (±SD) months, were randomly allocated to treatments in a double 4 × 4 Latin square design to investigate the effects of different levels of crude protein (CP) from sun-dried groundnut (Arachis hypogaea L.

The impact of body condition after calving on metabolism and milk progesterone profiles in two breeds of dairy cows.

Background: Optimal body condition in early lactation is generally accepted as a prerequisite for good reproductive performance. Examination of milk progesterone profiles offers an objective method for characterization of postpartum ovarian activity in dairy cows. The present study investigated the relationship between body condition after calving, some metabolic parameters in blood plasma, and fertility, as reflected by milk progesterone profiles in the two dairy breeds Swedish Red (SR) and Swedish Holstein (SH).

Short communication: Influence of shortening the dry period of Swedish dairy cows on plasmin activity in milk.

The aim of this study was to evaluate the influence of shortening the dry period of Swedish dairy cows on plasmin activity and casein composition in milk. Swedish Holstein and Swedish Red cows, 45 in total, were assigned to a dry period of either 4 or 8wk. Milk samples were taken 10 and 5wk prepartum, and 6 and 12wk postpartum.

Effect of shortening or omitting the dry period of Holstein-Friesian cows on casein composition of milk.

The aim of this study was to evaluate the effect of shortening or omitting the dry period of dairy cows on milk casein composition. For this study, we analyzed milk samples of 90 cows with a dry period of 0, 30, or 60d and either a glucogenic or a lipogenic ration in early lactation. Milk was sampled at 6 and 2wk prepartum and at 2, 6, and 12wk postpartum.

Survey of smallholder beef cattle production systems in different agro-ecological zones of Cambodia.

A survey was conducted to better understand the contribution of farm productivity to rural household income and identify differences in production systems, feeding practices and development constraints to smallholder beef cattle producers in the four agro-ecological zones (AEZs) of Cambodia. A semi-structured questionnaire was used to interview 360 households in the four AEZs: I, the Great Lake Floodplain; II, the Mekong Floodplain; III, the Coastal and IV, the Plateau/Mountainous. In addition, samples of common nutritional resources used for cattle feed were collected for nutrient composition analysis, plus cattle were scored for body condition.

Faecal excretion of total and acid extractable phosphorus in dairy cows fed rations with different levels of phosphorus.

Background: The phosphorus (P) originating from livestock operations causes eutrophication. Determination of acid extractable P (AEP) in cattle faeces has been proposed as a tool to identify excessive P feeding. The method has not yet been evaluated in controlled studies with cows subjected to individual recording of P intake.

Blood parameters in Swedish dairy herds with high or low incidence of displaced abomasum or ketosis.

Sixty dairy herds were studied to investigate the association between long-term incidence of displaced abomasum and clinical ketosis and body condition score and blood profiles, including parameters estimating energy metabolism and hepatic lipidosis in the periparturient period and early lactation. Blood samples were taken around parturition and in early lactation from cows without apparent clinical symptoms of metabolic disorders. A difference in metabolism between high and low incidence herds was shown post-partum by a lower metabolic index (the revised Quantitative Insulin Sensitivity Check Index, RQUICKI), and tendencies for higher concentrations of glucose, insulin and non-esterified fatty acids in the high incidence herds.

Metabolic profiles in five high-producing Swedish dairy herds with a history of abomasal displacement and ketosis.

Background: Body condition score and blood profiles have been used to monitor management and herd health in dairy cows. The aim of this study was to examine BCS and extended metabolic profiles, reflecting both energy metabolism and liver status around calving in high-producing herds with a high incidence of abomasal displacement and ketosis and to evaluate if such profiles can be used at herd level to pinpoint specific herd problems.

Methods: Body condition score and metabolic profiles around calving in five high-producing herds with high incidences of abomasal displacement and ketosis were assessed using linear mixed models (94 cows, 326 examinations).

A model to estimate insulin sensitivity in dairy cows.

Impairment of the insulin regulation of energy metabolism is considered to be an etiologic key component for metabolic disturbances. Methods for studies of insulin sensitivity thus are highly topical. There are clear indications that reduced insulin sensitivity contributes to the metabolic disturbances that occurs especially among obese lactating cows.