Polyana Pizzi Rotta

Universidade Federal de Viçosa (UFV) | UFV · Department of Animal Science

We aimed to estimate the protein requirements of pregnant Holstein × Gyr cows. Sixty-one Holstein × Gyr (HG) cows were used, with an average initial BW of 480 ± 10.1 kg and 5 ± 0.5 yrs of age. Cows were divided into 3 groups: pregnant (n = 43), non-pregnant (n = 12), and baseline (n = 6). Baseline animals were slaughtered before starting the experi...

Introduction The Nutrient Requirements of Dairy Cattle (NASEM, 2021) describes nutrient requirement as the daily amount of a specific nutrient necessary to meet a healthy cow’s needs for maintenance, activity, growth, reproduction, and lactation without changing the body reserves. It is well known that the nutrient requirements for pregnant cows w...

Holstein × Gyr and Holstein are the primary dairy breeds used in tropical systems, but when rearing under pasture, feed intake, behavior, and performance might differ between them. This study aimed to evaluate the voluntary intake, nutrient digestibility, performance, and ingestive behavior of Holstein and Holstein × Gyr (½ Holstein × ½ Gyr) heifer...

We aimed to evaluate the incidence of unstable non-acid milk (UNAM) in cows fed either sugarcane or corn silage. Second, we aimed to evaluate the effect of daily variation (d 1 to 4) and alcohol grades (72, 78, and 80%) on UNAM incidence. The experiment was conducted as a split-plot crossover design, with 2 periods and 2 roughage types (sugarcane o...

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The colostrum bacteriome of primiparous (P) and multiparous (M) Holstein cows was analysed by 16S rRNA sequencing. The species richness (Chao 1), diversity (Shannon and Simpson), and beta diversity did not differ between cow groups. The phyla Firmicutes, Tenericutes, Kiritimatiellaeota, and Fibrobacteres were more abundant in M cows, while Proteoba...

This study aimed to investigate the difference between Holstein and Holstein × Gyr breeds on feeding behavior and performance of heifers grazing temperate pasture. The experiment was carried out in 89 days, split into 14 days of adaptation, and 3 periods of 25 days. Two treatments were used: Holstein (HOL; n = 7) and Holstein × Gyr (HG; n = 7). Hei...

This study aimed to investigate the difference between Holstein and Holstein x Gyr breeds on feeding behavior and performance of heifers grazing temperate pasture. The experiment was carried out in 89 days, split into 14 days of adaptation and 3 periods of 25 days. Two treatments were used: Holstein (HOL; n = 7) and Holstein × Gyr (HG; n = 7). Heif...

Holstein × Gyr and Holstein are the primary dairy breed used in tropical systems, but when rearing under pasture, feed intake, behavior, and performance might differ between them. This study aimed to evaluate the voluntary intake, nutrient digestibility, performance, and ingestive behavior of Holstein and Holstein × Gyr (½ Holstein × ½ Gyr) heifers...

The use of supplements to feed grazing ruminants may improve the productivity and profitability of beef cattle productive systems. This study aimed to evaluate the effect of different supplementation amounts on the meat quality of Nellore steers finished on pasture. Forty steers were maintained on Brachiaria brizantha cv. Marandu pasture and finish...

The use of supplements to feed grazing ruminants may improve the productivity and profitability of beef cattle productive systems. This study aimed to evaluate the effect of different supplementation amounts on the meat quality of Nellore steers finished on pasture. A total of 40 steers were maintained on Brachiaria brizantha ‘Marandu’ pasture and...

Our objective was to estimate the nutrient intake, ruminal flow, total apparent and ruminal digestibility, rates of passage and digestion, ruminal and omasal pH, blood metabolite concentrations, and body measurements during the gestation of Holstein heifers. Eleven pregnant heifers, 8 of which were fitted with a rumen cannula (450 ± 27.6 kg of body...

A criação de bezerras e novilhas é uma das fases mais importantes para a pecuária leiteira, pois compreende a reposição genética que visa sempre a incorporação de animais mais produtivos e saudáveis nos rebanhos. Gerenciar os números e conhecer os principais índices zootécnicos é fundamental para traçar metas, estratégias e alcançar os objetivos, q...

This study aimed to estimate energy requirements of pregnant Holstein × Gyr cows. Different planes of nutrition were established by two feeding regimens: ad libitum or maintenance. Sixty-two nonlactating cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. Cows were divided into three groups: pregnant (n = 44), non-...

Neosporosis has become a concern since it is associated with abortion in cattle. Nowadays, in situ diagnosis is given through anamnesis, evaluation of the history and perception of the clinical signs of the herd. There is no practical and non-invasive test adapted to a large number of samples, which represents a gap for the use of new approaches th...

Our objective was to estimate nutrient intake, ruminal flow, total apparent and ruminal digestibility, rates of passage and digestion, ruminal and omasal pH, blood metabolite concentrations, and body measurements during gestation of Holstein heifers. Eleven pregnant Holstein heifers, 8 of which fitted with a rumen cannula (450 ± 27.6 kg of body wei...

Nutrient requirements in cattle are dependent on physiological stage, breed and environmental conditions. In Holstein × Gyr crossbred dairy heifers, the lack of data remains a limiting factor for estimating energy and protein requirements. Thus, we aimed to estimate the energy and protein requirements of Holstein × Gyr crossbred heifers raised unde...

This study aimed to determine body weight (BW), body condition score (BCS), and dairy type traits (DTT) of Holstein heifers and lactating cows using three-dimensional (3D) cameras, in addition to evaluating the sensitivity of this system over time and the best sensor position. Twenty-eight cows and twenty-seven heifers were used. Measurements of BW...

This study aimed to evaluate the effects of plane of nutrition and advancing days of pregnancy (DP) on maternal body composition and fetal development. Differing planes of nutrition were established by 2 feeding regimens (FR): ad libitum (AL) or maintenance (MA). Sixty-two nonlactating multiparous Holstein × Gyr cows with average body weight of 480...

Calf rearing is one of the most important periods in the production cycle in dairy farming. It comprises genetic replacement, always targeting increasingly productive and healthy animals in the future of the herd. Knowing how to manage numbers and having the knowledge of the main zootechnical indices is important to achieve the goals, set goals and...

Calf rearing is one of the most important periods in the production cycle in dairy farming. It comprises genetic replacement, always targeting increasingly productive and healthy animals in the future of the herd. Knowing how to manage numbers and having the knowledge of the main zootechnical indices is important to achieve the goals, set goals and...

The literature lacks studies investigating the performance of supplemented replacement heifers grazing on intensively managed warm-season pasture. Our objective was to evaluate the effects of supplement composition (energetic or protein) on the performance, muscle development, thermogenisis, nutrient intake, and digestibility of replacement Holstei...

The aim was to evaluate the effect of different feed additives on intake, performance, and fecal consistency index (FCI) of dairy calves from 6–60 d of age and its residual effect 15 d after weaning. Fifty Holstein calves (38 ± 1.0 kg BW) were fed 5 L/d of milk plus starter feed until weaning, and corn silage and concentrate after weaning. The trea...

Dataset used in the present study. (XLSX)

Primer sequence, product length (base pairs-bp), and annealing temperature (°C) used for PCR in calves receiving mineral supplementation with monensin, probiotic Enterococcus faecium NCIMB 10415, essential oils, probiotic + essential oils or mineral control. (DOCX)

International committees that have published nutrient requirements for dairy cattle have used data from mineral studies conducted in the 1920s to 1970s, and no study has reported data from animals less than 100 kg; therefore, there is a need to update mineral requirements for preweaned dairy calves. Thus, a meta-analysis was performed to estimate t...

Results of a survey carried out with the management of dairy calves in Brazil, in 2018.

The aim of this work was to evaluate the influence of increasing amounts of rumen undegradable protein (RUP) on intake, nutrient digestibility, rumen kinetics and fermentation characteristics and N use efficiency of dairy Holstein heifers. Eight rumen-cannulated Holstein heifers (initial body weight 276 ± 8.3 kg) were used in a replicate 4 × 4 Lati...

To determine the effects of maternal nutrition on modifications of foetal development of the skeletal muscle and possible increase in the potential of skeletal muscle growth in cattle, gestating cows were either fed 190% NRC recommendations (overnourished; ON) or 100% NRC recommendation (control; CO). Interaction between maternal nutrition (MN) and...

The effects of microbial contamination (MC) on CP degradability of concentrate feeds are still controversial. Therefore, the aim of this study was to use¹⁵N to estimate the impact of MC on estimations of CP fractions (the soluble fraction of CP [a], the insoluble but potentially degradable fraction of CP [b], and the rate of digestion of fraction b...

The effects of microbial contamination (MC) on CP degradability of concentrate feeds are still controversial. Therefore, the aim of this study was to use N to estimate the impact of MC on estimations of CP fractions (the soluble fraction of CP [a], the insoluble but potentially degradable fraction of CP [b], and the rate of digestion of fraction b...

The objective of the current study was to quantify the dry matter (DM) digestibility, and total ash (TA) and mineral release from 12 concentrate and 12 forage feedstuffs commonly fed to cattle using in situ and in vitro methods. Concentrate and forage feedstuffs were incubated in the rumen of ruminally cannulated beef bulls at eight different time...

There is little information regarding the nutritional requirements for dairy heifers, leading the majority of nutrient requirement systems to consider dairy heifers to be similar to beef heifers. Therefore, we evaluated the muscle protein metabolism and physical and chemical body composition of growing Holstein × Gyr heifers and estimated the energ...

We aimed to evaluate the effects of maternal nutrition (MN) and foetal sex on the intestinal development of bovine foetuses throughout different days of gestation (DG). Forty-four multiparous, dry Holstein × Gyr cows with average initial body weight of 480 ± 10 kg were fed the same diet of either restricted feeding at 1.15% of body weight (CO, n =...

This study investigated effects of maternal overnutrition on gonadal development and pituitary-gonadal gene expression in cattle fetuses at mid- and late-gestation. Twenty-seven multiparous dry cows were fed either high (ad libitum, H) or moderate (M) intake of the same diet. Twelve cows from H (n = 6) and M (n = 6) intake carrying females fetuses...

The aim of this study was to evaluate the effect of diets containing corn silage (CS) or sugarcane (SC) with 300 or 500 g/kg of concentrate (on a DM basis) on energy conversion, enteric methane (CH4) production, and the animal performance of Holstein × Zebu heifers. An experiment was conducted while using comparative slaughter. Twenty Holstein × Ze...

Eighty-seven Nellore animals were utilized in this study to estimate net requirements for the maintenance and growth of beef cattle as well as the retention coefficients of 13 minerals: macrominerals (Ca, P, Mg, K, Na, and S) and trace elements (Cu, Fe, Mn, Se, Zn, Co, and Cr). The net requirements for maintenance and the true retention coefficient...

The spreadsheet included as supporting information can be used to meet mineral requirements for maintenance and growth such as dietary requirements using different body weights and average daily gain. (XLSX)

Data showing how mineral requirements for maintenance and growth were achieved. (XLS)

Nutrient apparent digestibility, intake, performance, microbial efficiency, and energy and protein requirements for growing Nellore heifers and steers were evaluated, fifty animals were used, 32 Nellore heifers and 18 Nellore steers. Four animals of each gender used as baseline reference animals were slaughtered at the beginning of the experiment....

Foram avaliados o consumo, as digestibilidades totais e ruminais e as taxas de digestão (kd) e de passagem (kp) ruminal dos nutrientes de dietas constituídas de cana-de-açúcar in naturae diferentes níveis de concentrado. Utilizaram-se cinco bovinos mestiços, fistulados no rúmen, com peso corporal inicial de 300±50kg, distribuídos em delineamento em...

This study investigated the influence of day of gestation (DG) and feeding regimens (FR) on the expression of genes responsible for placenta development, nutrient transfer, and angiogenic factors in Holstein × Gyr cows. Forty pregnant multiparous Holstein × Gyr cows with an average initial body weight of 482 ± 10.8 kg and an initial age of 5 ± 0.8...

An experiment was conducted to evaluate intake and nutrient digestibility, performance, milk composition, and microbial efficiency of Nellore cows and their calves during lactation. Fifteen Nellore cows were fed corn silage and concentrate (85:15). After calving, calves were kept with their dams for 2 months then separated and housed in individual...

This study investigated the influence of day of gestation (DG) and feeding regimens (FR) on maternal and fetal visceral organ mass in Holstein × Gyr cows. Forty-four pregnant multiparous Holstein × Gyr cows with an average initial body weight of 480 ± 10.1 kg and an average initial age of 5 ± 0.5 yr were allocated to 1 of 2 FR: ad libitum (AL; n =...

This study investigated how feeding regimen (FR) alters apparent total-tract digestibility, performance, N balance, excretion of purine derivatives, and fat deposition in Holstein × Gyr cows at different days of gestation (DG). Forty-four pregnant multiparous Holstein × Gyr cows with an average initial body weight of 480 ± 10.1 kg and an initial ag...

The present experiment was designed to evaluate the use of microbial markers (MM), sampling sites (SS), and marker systems (MS) to estimate microbial nitrogen (MN) synthesis in bulls and to develop equations to correct MN estimates when only one of the aforementioned techniques was utilized. The MM systems evaluated were 1) purine bases (PB) and 2)...

Abstract Text: An experiment was conducted to evaluate intake and nutrient digestibility of Nellore heifers and steers fed two levels of calcium and phosphorus. Thirty two Nellore heifers and eighteen Nellore steers were used. Four animals from each gender were used as baseline reference animals and slaughtered at the beginning of the experiment. F...

Abstract Text: An experiment was conducted to evaluate the energy and protein requirements for growing Nellore heifers and steers fed with two levels of calcium and phosphorus. Thirty two Nellore heifers and eighteen Nellore steers were used. Heifers were divided in four groups. Four animals served as baseline reference animals, four were fed at ma...