The objective was to evaluate the performance of suckling piglets based on their choice of mammary gland. A completely randomized design was used, considering the position of the mammary glands pair and their respective piglets as experimental unit. The mammary gland position was considered for the treatments, being 1st, 4th and 7th pair. The ration and leftovers were weighed daily to obtain daily feed intake of the sow. On post-natal day (PND) 3 and 21, 80 ml of milk was collected to analyse crude protein, fat, lactose, non-fatty solids, mineral matter and total solids. On PND 3 and 21, the piglets were weighed to determine weight gain and estimate milk consumption. The piglets' longitudinal length and head circumference were measured in the same period and estimated body surface area/mass ratio. Blood samples from the sows and piglets were collected on PND 3 and 21 to analyse total cholesterol, triglycerides, total protein, fractions and glucose. There was an effect of mammary gland position on piglets at PND 21 suckling on the 7th pair, which had a 23.88 cm2/kg greater body surface/mass ratio compared to those who suckled in the 1st pair. In turn, at PND 21, the piglets that suckled in the 1st pair presented higher weight, weight gain and milk consumption (0.685, 0.033 and 0.127 kg, respectively) than those that suckled in the 7th pair. Anterior mammary glands result in better productive performance and better chances of maintaining piglet homeostasis at PND 21.

We address the hypothesis that at early and late lactation milk presents low ethanol stability due to high acidity and ionic calcium values. Our aim was to evaluate the functional traits of milk (milk ethanol stability: MES, acidity and ionic calcium: iCa) according to lactation stage in different genetic groups. Raw milk samples were collected from Jersey (n = 271), Holstein (n = 248) and Jersey × Holstein crossbred cows (n = 82), raised on five commercial farms located in the state of Paraná, Brazil. Milk composition, somatic cell count (SCC), milk urea nitrogen (MUN), MES, pH, acidity and iCa were determined. Days in milk (DIM) were categorized into four classes: 1–60, 61–150, 151–305 and over 305 DIM. Data were submitted to analysis of variance. Fixed and random effects were incorporated into the model, in a repeated measures in time arrangement using the mixed models methodology. Significant interactions between DIM class and genetic groups were detected. The comparison between each combination of genetic group and DIM class showed that at the beginning of lactation, Holsteins produced milk with higher MES than Jersey and crossbreds. At 105–305 DIM Holstein milk presented higher MES than Jersey, while beyond 305 DIM Holstein milk showed higher MES than crossbred cows. At the beginning of lactation acidity was higher in Holstein milk and crossbreds compared with Jersey, while acidity was lower in Holstein milk compared with Jersey and crossbreds in the other lactation stages. Ionic calcium was highest after lactation peak for Holstein, but did not vary between lactation stages for Jersey and crossbreds. Functional characteristics of bovine raw milk such as MES, iCa and acidity varied between lactation stages in a distinct manner according to genetic groups. Early and end lactation stages are challenging in terms of low stability, especially for Jersey and crossbreds.