The purpose of the research was to assess changes in lactation activity cows and their impact on level reproduction, as well study fluctuations with respect genetic environmental factors. A sample 807 various ages formed for study. were kept a commercial farm Kharkiv region, Ukraine. Data from DairyPlan C21 software used It revealed that parameters Wood curve model significantly influenced by c...

The purpose of this study was to find a well-fitting, robust, single-equation model to describe the shape of lactation curves for Irish dairy cows. The suitability of a number of algebraic models that depict lactation curves was examined, using Irish test day data. The analysis was carried out on a total of 14,956 lactation records from commercial and experimental herds and included both autumn...

Concerns have been raised in the past about the Dairy Herd Improvement Association recording frequency, because the interval between samples, about 4 weeks, may not capture the peak production for cows with shorter lactation (less than 10 mo), which have led to the conclusion that these cows have an atypical lactation curve shape. This may be due to sampling frequency rather than biological dif...

Standard Lactation Curves were derived for South African Holstein and Jersey cows, using 20 herd-, 18 ageand six season classes. Six herd classes were below and 13 above the average production level for both breeds. A standard lactation curve was estimated for each combination of herd-, ageand season class, which resulted in 2 160 curves per trait per breed. Variation in Holstein yields was muc...

Milk yield and composition data from 7 nursing Lusitano mares (450 to 580 kg of body weight and 2 to 9 parities) were used in this study (5 measurements per mare for milk yield and 8 measurements for composition). Wood's lactation model was used to describe milk fat, protein, and lactose lactation curves. Mean values for the concentration of major milk components across the lactation period (18...

Variables derived from milk yield records were investigated to find an easy to measure and readily available indicator of the energy balance status of a lactating cow. Weekly energy balances during the first 180 d in milk (DIM) were calculated from weekly yield, live weight, and energy intake records for 470 first lactation heifers. The energy balance curve for each cow was estimated using a ra...

Lactation curves are a graphical representation of the milk production profile of a doe from parturition to drying up. Their shape provides information about the productivity of the doe and offers a means of explaining features of the milk production patterns of each animal. A total of 2732 daily morning milk records from 610 does of the Kenyan Alpine dairy goats’ genetic groups (50% Alpine, 75...

Valacta (Sainte-Anne-de-Bellevue, Québec, Canada) is the Canadian Dairy Herd Improvement organization responsible for milk recording in Québec and Atlantic provinces. Up to 14 first-lactation body condition score (BCS) records were collected per cow (average of 2.5 records per cow), allowing the trait to be described by a random regression animal model so that animals could be ranked by the sha...